Re: [Cal_Boats] Serious battery question (Al)

Al - Right now I have two 12-volt batties in parallel for starting my 56hp Yanmar and two 6-volt batteries in series for the house batteries. The boat was this way when I bought it. However, the house lights stay on no matter where the battery switch is. I've not conducted a test to see what all works and doesn't work when the switch is set to one or two, but with all the other wiring fiascos I've found I am assuming that I essentially have one big ass battery bank. My question to you however is in regard to your statement below about wiring the batteries in parallel and if done this way if one goes bad it takes out the other one. If you don't wire them this way, what is the other option? Keep 2 batteries but only connect one and keep the other as a spare and keep it charged in some manner? I hope to be re-wiring my boat soon and if there is a better option I'd love to hear it. Thanks - Paul West I'm also assuming that you would put the new house battery in parallel with the existing one, although I'm not convinced that is the best approach - in a parallel situation when one battery goes it usually takes the other with it so you end up having to change both batteries when one dies.

I think you meant the other Al but I can chime in on the batteries. I think what he meant is that if a battery goes bad, dead, end of life, it may take the others it is connected in parallel with it. What I do with the 3 batteries I have on my motor home is always replace all 3 at the same time and wire them in parallel. But to answer the question asked, the alternative to wiring them in parallel is to have a battery selector switch. Allen also an old EE. On Thu, Sep 30, 2010 at 6:13 PM, <pw… [at] aol.com> wrote: > > > > Al - > > Right now I have two 12-volt batties in parallel for starting my 56hp > Yanmar and two 6-volt batteries in series for the house batteries. The boat > was this way when I bought it. However, the house lights stay on no matter > where the battery switch is. I've not conducted a test to see what all > works and doesn't work when the switch is set to one or two, but with all > the other wiring fiascos I've found I am assuming that I essentially have > one big ass battery bank. My question to you however is in regard to your > statement below about wiring the batteries in parallel and if done this way > if one goes bad it takes out the other one. If you don't wire them this > way, what is the other option? Keep 2 batteries but only connect one and > keep the other as a spare and keep it charged in some manner? I hope to be > re-wiring my boat soon and if there is a better option I'd love to hear it. > > Thanks - > > Paul West > > I'm also assuming that you would put the new house battery in parallel with > the existing one, although I'm not convinced that is the best approach - in > a parallel situation when one battery goes it usually takes the other with > it so you end up having to change both batteries when one dies. > > >

Sorry, I didn't see the other post. There are several alternatives. The most recommended one I have seen is to have three battery switches, two of them should be two position, i.e. ON/OFF. One ON/OFF switch is wired to the engine and to the starting battery. A third switch OFF/1/BOTH/2, is wired to the house loads and to two house batteries. The other ON/OFF switch is wired between the commons of the two other switches. Placing it in the ON position bridges the house and starting banks. It is recommended that this switch have a set of auxiliary contacts (field disconnect contacts would work here) that are used to sound an alarm when it is activated to remind you that you have the systems bridged and the house loads can bring down the starting battery. A variant of this is to use two cascaded OFF/1/BOTH/2 switches. Switch one common is connected to the engine, position one is connected to the starting battery, and position 2 is connected to the common of switch 2 which is also connected to the house loads. Positions 1 and 2 of switch 2 are connected to house batteries. This configuration is simpler, but it may be easier to get confused and run down the starting battery. In either case, only the battery connected to the engine gets charged when the engine is running unless you set both switches to both or have a battery combiner. This is the arrangement I'm thinking about to add a starting battery to my 33. Currently she has two house batteries on a single OFF/1/BOTH/2 switch. My setup (factory wiring) uses whatever is selected for all loads, starting and house. My experience with parallel batteries was years ago (wet cell lead/acid technology hasn't changed that much, I don't think) when GM used two batteries in parallel to start their HORRIBLE V-8 diesel engine that I got sucked into buying. Try as I might, I was never successful at replacing only one battery. With age, the fully charged voltage goes down and the internal resisance goes up, the net result is the newer battery works harder and degrades faster. When two batteries are in parallel, the one wth the higher level of charge will discharge into the other one to equalize charge, but the laws of physics dictate that half the energy in that exchange is lost. Hope this is helpful. Al --- On Thu, 9/30/10, Allen Edwards <al… [at] PaloAltoPhoto.com> wrote: From: Allen Edwards <al… [at] PaloAltoPhoto.com> Subject: Re: [Cal_Boats] Serious battery question (Al) To: Ca… [at] yahoogroups.com Date: Thursday, September 30, 2010, 11:42 PM I think you meant the other Al but I can chime in on the batteries. I think what he meant is that if a battery goes bad, dead, end of life, it may take the others it is connected in parallel with it. What I do with the 3 batteries I have on my motor home is always replace all 3 at the same time and wire them in parallel. But to answer the question asked, the alternative to wiring them in parallel is to have a battery selector switch. Allen also an old EE. On Thu, Sep 30, 2010 at 6:13 PM, <pw… [at] aol.com> wrote: Al - Right now I have two 12-volt batties in parallel for starting my 56hp Yanmar and two 6-volt batteries in series for the house batteries. The boat was this way when I bought it. However, the house lights stay on no matter where the battery switch is. I've not conducted a test to see what all works and doesn't work when the switch is set to one or two, but with all the other wiring fiascos I've found I am assuming that I essentially have one big ass battery bank. My question to you however is in regard to your statement below about wiring the batteries in parallel and if done this way if one goes bad it takes out the other one. If you don't wire them this way, what is the other option? Keep 2 batteries but only connect one and keep the other as a spare and keep it charged in some manner? I hope to be re-wiring my boat soon and if there is a better option I'd love to hear it. Thanks - Paul West I'm also assuming that you would put the new house battery in parallel with the existing one, although I'm not convinced that is the best approach - in a parallel situation when one battery goes it usually takes the other with it so you end up having to change both batteries when one dies.

Regarding the equalization of charge with two batteries in parallel, there is energy loss, but it is situation dependent. The half figure I was referring to is when charge is equalized on two capacitors. Al

Glad you clarified that. I was about to go nuts. I knew about the capacitors (1/2 CV^2 and all that) but I was not sure how it related to batteries. When two batteries are in parallel, they will always be at the same voltage. There may be some charge transfer after the load is removed and they come back up to resting voltage but my mind explodes when I try and figure that out. "In situations where multiple batteries are connected in series, parallel or series/parallel, replacement batteries should be the same size, type and manufacturer (if possible). Age and usage level should be the same as the companion batteries. Do not put a new battery in a pack which is more than 6 months old or has more than 75 cycles. Either replace with all new or use a good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm I think that is the bottom line. If you run batteries in parallel or series, replace all of them when one needs replacing. This is another interesting reference http://www.yuasabatteries.com/pdfs/TechMan.pdf Allen On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net> wrote: > > > > Regarding the equalization of charge with two batteries in parallel, there > is energy loss, but it is situation dependent. The half figure I was > referring to is when charge is equalized on two capacitors. > > Al > > >

To: Al, Allan, Tim, and everyone else who has tried to help ... First, thanks for all of your advice. The history of all this is my 2005 TransPac race. I did have 2 "4-D" batteries in parallel. Believing that charging was most productive if the initial battery voltage was relatively low, we'd gone nearly 24 hours without charging. We started up the engine just fine, and turned on the water-maker. An hour later I looked at the Link 2000 amp/volt meter and realized that we were not charging. We had a sat-phone and were able to reach our engine mechanic. His assessment was that we had blown the diodes on the alternator, and since it never occurred to me to carry a spare alternator, nothing could be done. At the time, the alternator (and engine) were running in a relatively small, confined engine box. I never determined exactly what it was caused the diodes to blow. The two most likely culprits seemed to be either too much heat, too much demand on the alternator caused by the two low batteries, or some combination of the two. Obviously, my main goal here is to not repeat that blown diode situation Since then, I cut two big (6") holes in my engine box, one to the side, and one to the rear of the alternator. This should really help with the cooling-of-the-alternator issue. Al .. yes, I have a combiner. I don't see a problem there. The engine starting battery is always connected to the alternator. Once the alternator come up to charging voltage, the combiner "combines", and links the house batteries to the alternator.

Check how your combiner is hooked up if it is the diode kind. It is possible to hook the diode kind up so that the house batteries would never get fully charged. Allen On Fri, Oct 1, 2010 at 6:44 AM, Fin Beven <fi… [at] msn.com> wrote: > > >  > To: Al, Allan, Tim, and everyone else who has tried to help ... > > First, thanks for all of your advice. > > The history of all this is my 2005 TransPac race. > > I did have 2 "4-D" batteries in parallel. Believing that charging was most > productive if the initial battery voltage was relatively low, we'd gone > nearly 24 hours without charging. We started up the engine just fine, and > turned on the water-maker. An hour later I looked at the Link 2000 > amp/volt meter and realized that we were not charging. We had a sat-phone > and were able to reach our engine mechanic. His assessment was that we > had blown the diodes on the alternator, and since it never occurred to me to > carry a spare alternator, nothing could be done. > > At the time, the alternator (and engine) were running in a relatively > small, confined engine box. I never determined exactly what it was caused > the diodes to blow. The two most likely culprits seemed to be either too > much heat, too much demand on the alternator caused by the two low > batteries, or some combination of the two. > > Obviously, my main goal here is to not repeat that blown diode situation > > Since then, I cut two big (6") holes in my engine box, one to the side, and > one to the rear of the alternator. This should really help with the > cooling-of-the-alternator issue. > > Al .. yes, I have a combiner. I don't see a problem there. The engine > starting battery is always connected to the alternator. Once the > alternator come up to charging voltage, the combiner "combines", and links > the house batteries to the alternator. > > From all that all of you have written, I'm inclined to add the additional > 4-D house battery, and hope that the extra cooling air around my alternator > will solve the problem. > > Again, thanks to all. > > Fin. > > ----- Original Message ----- > *From:* Al Waschka <aw… [at] bellsouth.net> > *To:* Ca… [at] yahoogroups.com > *Sent:* Thursday, September 30, 2010 9:27 PM > *Subject:* Re: [Cal_Boats] Serious battery question (Al) > > Sorry, I didn't see the other post. There are several alternatives. > The most recommended one I have seen is to have three battery switches, two > of them should be two position, i.e. ON/OFF. One ON/OFF switch is wired to > the engine and to the starting battery. A third switch OFF/1/BOTH/2, is > wired to the house loads and to two house batteries. The other ON/OFF > switch is wired between the commons of the two other switches. Placing it > in the ON position bridges the house and starting banks. It is recommended > that this switch have a set of auxiliary contacts (field disconnect contacts > would work here) that are used to sound an alarm when it is activated to > remind you that you have the systems bridged and the house loads can bring > down the starting battery. > > A variant of this is to use two cascaded OFF/1/BOTH/2 switches. Switch one > common is connected to the engine, position one is connected to the starting > battery, and position 2 is connected to the common of switch 2 which is also > connected to the house loads. Positions 1 and 2 of switch 2 are connected > to house batteries. This configuration is simpler, but it may be easier to > get confused and run down the starting battery. In either case, only the > battery connected to the engine gets charged when the engine is running > unless you set both switches to both or have a battery combiner. This is > the arrangement I'm thinking about to add a starting battery to my 33. > Currently she has two house batteries on a single OFF/1/BOTH/2 switch. My > setup (factory wiring) uses whatever is selected for all loads, starting and > house. > > My experience with parallel batteries was years ago (wet cell lead/acid > technology hasn't changed that much, I don't think) when GM used two > batteries in parallel to start their HORRIBLE V-8 diesel engine that I got > sucked into buying. Try as I might, I was never successful at replacing > only one battery. With age, the fully charged voltage goes down and the > internal resisance goes up, the net result is the newer battery works harder > and degrades faster. When two batteries are in parallel, the one wth the > higher level of charge will discharge into the other one to equalize charge, > but the laws of physics dictate that half the energy in that exchange is > lost. > > Hope this is helpful. > > Al > > > --- On *Thu, 9/30/10, Allen Edwards <al… [at] PaloAltoPhoto.com>*wrote: > > > From: Allen Edwards <al… [at] PaloAltoPhoto.com> > Subject: Re: [Cal_Boats] Serious battery question (Al) > To: Ca… [at] yahoogroups.com > Date: Thursday, September 30, 2010, 11:42 PM > > > I think you meant the other Al but I can chime in on the batteries. I > think what he meant is that if a battery goes bad, dead, end of life, it may > take the others it is connected in parallel with it. What I do with the 3 > batteries I have on my motor home is always replace all 3 at the same time > and wire them in parallel. But to answer the question asked, > the alternative to wiring them in parallel is to have a battery selector > switch. > > Allen > also an old EE. > > On Thu, Sep 30, 2010 at 6:13 PM, <pw… [at] aol.com<http://us.mc1806.mail.yahoo.com/mc/compose?to=pw… [at] aol.com> > > wrote: > > > > Al - > > Right now I have two 12-volt batties in parallel for starting my 56hp > Yanmar and two 6-volt batteries in series for the house batteries. The boat > was this way when I bought it. However, the house lights stay on no matter > where the battery switch is. I've not conducted a test to see what all > works and doesn't work when the switch is set to one or two, but with all > the other wiring fiascos I've found I am assuming that I essentially have > one big ass battery bank. My question to you however is in regard to your > statement below about wiring the batteries in parallel and if done this way > if one goes bad it takes out the other one. If you don't wire them this > way, what is the other option? Keep 2 batteries but only connect one and > keep the other as a spare and keep it charged in some manner? I hope to be > re-wiring my boat soon and if there is a better option I'd love to hear it. > > Thanks - > > Paul West > > I'm also assuming that you would put the new house battery in parallel with > the existing one, although I'm not convinced that is the best approach - in > a parallel situation when one battery goes it usually takes the other with > it so you end up having to change both batteries when one dies. > > > >

Alan ... thanks. It's a Blue-Sea combiner, wired to factory instructions. Once it "combines", the house batteries seem to be getting full output from the alternator. ----- Original Message ----- From: Allen Edwards<mailto:al… [at] PaloAltoPhoto.com> To: Ca… [at] yahoogroups.com<mailto:Ca… [at] yahoogroups.com> Sent: Friday, October 01, 2010 7:54 AM Subject: Re: [Cal_Boats] Serious battery question (Al) Check how your combiner is hooked up if it is the diode kind. It is possible to hook the diode kind up so that the house batteries would never get fully charged. Allen On Fri, Oct 1, 2010 at 6:44 AM, Fin Beven <fi… [at] msn.com<mailto:fi… [at] msn.com>> wrote:  To: Al, Allan, Tim, and everyone else who has tried to help ... First, thanks for all of your advice. The history of all this is my 2005 TransPac race. I did have 2 "4-D" batteries in parallel. Believing that charging was most productive if the initial battery voltage was relatively low, we'd gone nearly 24 hours without charging. We started up the engine just fine, and turned on the water-maker. An hour later I looked at the Link 2000 amp/volt meter and realized that we were not charging. We had a sat-phone and were able to reach our engine mechanic. His assessment was that we had blown the diodes on the alternator, and since it never occurred to me to carry a spare alternator, nothing could be done. At the time, the alternator (and engine) were running in a relatively small, confined engine box. I never determined exactly what it was caused the diodes to blow. The two most likely culprits seemed to be either too much heat, too much demand on the alternator caused by the two low batteries, or some combination of the two. Obviously, my main goal here is to not repeat that blown diode situation Since then, I cut two big (6") holes in my engine box, one to the side, and one to the rear of the alternator. This should really help with the cooling-of-the-alternator issue. Al .. yes, I have a combiner. I don't see a problem there. The engine starting battery is always connected to the alternator. Once the alternator come up to charging voltage, the combiner "combines", and links the house batteries to the alternator. From all that all of you have written, I'm inclined to add the additional 4-D house battery, and hope that the extra cooling air around my alternator will solve the problem. Again, thanks to all. Fin. ----- Original Message ----- From: Al Waschka<mailto:aw… [at] bellsouth.net> To: Ca… [at] yahoogroups.com<mailto:Ca… [at] yahoogroups.com> Sent: Thursday, September 30, 2010 9:27 PM Subject: Re: [Cal_Boats] Serious battery question (Al) Sorry, I didn't see the other post. There are several alternatives. The most recommended one I have seen is to have three battery switches, two of them should be two position, i.e. ON/OFF. One ON/OFF switch is wired to the engine and to the starting battery. A third switch OFF/1/BOTH/2, is wired to the house loads and to two house batteries. The other ON/OFF switch is wired between the commons of the two other switches. Placing it in the ON position bridges the house and starting banks. It is recommended that this switch have a set of auxiliary contacts (field disconnect contacts would work here) that are used to sound an alarm when it is activated to remind you that you have the systems bridged and the house loads can bring down the starting battery. A variant of this is to use two cascaded OFF/1/BOTH/2 switches. Switch one common is connected to the engine, position one is connected to the starting battery, and position 2 is connected to the common of switch 2 which is also connected to the house loads. Positions 1 and 2 of switch 2 are connected to house batteries. This configuration is simpler, but it may be easier to get confused and run down the starting battery. In either case, only the battery connected to the engine gets charged when the engine is running unless you set both switches to both or have a battery combiner. This is the arrangement I'm thinking about to add a starting battery to my 33. Currently she has two house batteries on a single OFF/1/BOTH/2 switch. My setup (factory wiring) uses whatever is selected for all loads, starting and house. My experience with parallel batteries was years ago (wet cell lead/acid technology hasn't changed that much, I don't think) when GM used two batteries in parallel to start their HORRIBLE V-8 diesel engine that I got sucked into buying. Try as I might, I was never successful at replacing only one battery. With age, the fully charged voltage goes down and the internal resisance goes up, the net result is the newer battery works harder and degrades faster. When two batteries are in parallel, the one wth the higher level of charge will discharge into the other one to equalize charge, but the laws of physics dictate that half the energy in that exchange is lost. Hope this is helpful. Al --- On Thu, 9/30/10, Allen Edwards <al… [at] PaloAltoPhoto.com> wrote: From: Allen Edwards <al… [at] PaloAltoPhoto.com> Subject: Re: [Cal_Boats] Serious battery question (Al) To: Ca… [at] yahoogroups.com<mailto:Ca… [at] yahoogroups.com> Date: Thursday, September 30, 2010, 11:42 PM I think you meant the other Al but I can chime in on the batteries. I think what he meant is that if a battery goes bad, dead, end of life, it may take the others it is connected in parallel with it. What I do with the 3 batteries I have on my motor home is always replace all 3 at the same time and wire them in parallel. But to answer the question asked, the alternative to wiring them in parallel is to have a battery selector switch. Allen also an old EE. On Thu, Sep 30, 2010 at 6:13 PM, <pw… [at] aol.com<http://us.mc1806.mail.yahoo.com/mc/compose?to=pw… [at] aol.com>> wrote: Al - Right now I have two 12-volt batties in parallel for starting my 56hp Yanmar and two 6-volt batteries in series for the house batteries. The boat was this way when I bought it. However, the house lights stay on no matter where the battery switch is. I've not conducted a test to see what all works and doesn't work when the switch is set to one or two, but with all the other wiring fiascos I've found I am assuming that I essentially have one big ass battery bank. My question to you however is in regard to your statement below about wiring the batteries in parallel and if done this way if one goes bad it takes out the other one. If you don't wire them this way, what is the other option? Keep 2 batteries but only connect one and keep the other as a spare and keep it charged in some manner? I hope to be re-wiring my boat soon and if there is a better option I'd love to hear it. Thanks - Paul West I'm also assuming that you would put the new house battery in parallel with the existing one, although I'm not convinced that is the best approach - in a parallel situation when one battery goes it usually takes the other with it so you end up having to change both batteries when one dies.

Finn, I'm going to go with heat as the problem. If your alternator is relatively new (design, that is) I don't think the alternator will put out any more current into two (or three) batteries in parallel, it will just take longer to charge the more batteries you have. So minimizing heat is really important. I think you are on the right track. Al --- On Fri, 10/1/10, Fin Beven <fi… [at] msn.com> wrote: From: Fin Beven <fi… [at] msn.com> Subject: Re: [Cal_Boats] Serious battery question (Al) To: Ca… [at] yahoogroups.com Date: Friday, October 1, 2010, 9:44 AM  To: Al, Allan, Tim, and everyone else who has tried to help ... First, thanks for all of your advice. The history of all this is my 2005 TransPac race. I did have 2 "4-D" batteries in parallel. Believing that charging was most productive if the initial battery voltage was relatively low, we'd gone nearly 24 hours without charging. We started up the engine just fine, and turned on the water-maker. An hour later I looked at the Link 2000 amp/volt meter and realized that we were not charging. We had a sat-phone and were able to reach our engine mechanic. His assessment was that we had blown the diodes on the alternator, and since it never occurred to me to carry a spare alternator, nothing could be done. At the time, the alternator (and engine) were running in a relatively small, confined engine box. I never determined exactly what it was caused the diodes to blow. The two most likely culprits seemed to be either too much heat, too much demand on the alternator caused by the two low batteries, or some combination of the two. Obviously, my main goal here is to not repeat that blown diode situation Since then, I cut two big (6") holes in my engine box, one to the side, and one to the rear of the alternator. This should really help with the cooling-of-the-alternator issue. Al .. yes, I have a combiner. I don't see a problem there. The engine starting battery is always connected to the alternator. Once the alternator come up to charging voltage, the combiner "combines", and links the house batteries to the alternator.

I see it is a voltage sensitive relay so would not have the problem of the old diode combiners. Allen On Fri, Oct 1, 2010 at 8:11 AM, Fin Beven <fi… [at] msn.com> wrote: > > >  > Alan ... thanks. It's a Blue-Sea combiner, wired to factory > instructions. Once it "combines", the house batteries seem to be getting > full output from the alternator. > > ----- Original Message ----- > *From:* Allen Edwards <al… [at] PaloAltoPhoto.com> > *To:* Ca… [at] yahoogroups.com > *Sent:* Friday, October 01, 2010 7:54 AM > *Subject:* Re: [Cal_Boats] Serious battery question (Al) > > Check how your combiner is hooked up if it is the diode kind. It is > possible to hook the diode kind up so that the house batteries would never > get fully charged. > > Allen > > On Fri, Oct 1, 2010 at 6:44 AM, Fin Beven <fi… [at] msn.com> wrote: > >> >> >>  >> To: Al, Allan, Tim, and everyone else who has tried to help ... >> >> First, thanks for all of your advice. >> >> The history of all this is my 2005 TransPac race. >> >> I did have 2 "4-D" batteries in parallel. Believing that charging was >> most productive if the initial battery voltage was relatively low, we'd >> gone nearly 24 hours without charging. We started up the engine just fine, >> and turned on the water-maker. An hour later I looked at the Link 2000 >> amp/volt meter and realized that we were not charging. We had a sat-phone >> and were able to reach our engine mechanic. His assessment was that we >> had blown the diodes on the alternator, and since it never occurred to me to >> carry a spare alternator, nothing could be done. >> >> At the time, the alternator (and engine) were running in a relatively >> small, confined engine box. I never determined exactly what it was caused >> the diodes to blow. The two most likely culprits seemed to be either too >> much heat, too much demand on the alternator caused by the two low >> batteries, or some combination of the two. >> >> Obviously, my main goal here is to not repeat that blown diode situation >> >> Since then, I cut two big (6") holes in my engine box, one to the side, >> and one to the rear of the alternator. This should really help with the >> cooling-of-the-alternator issue. >> >> Al .. yes, I have a combiner. I don't see a problem there. The engine >> starting battery is always connected to the alternator. Once the >> alternator come up to charging voltage, the combiner "combines", and links >> the house batteries to the alternator. >> >> From all that all of you have written, I'm inclined to add the additional >> 4-D house battery, and hope that the extra cooling air around my alternator >> will solve the problem. >> >> Again, thanks to all. >> >> Fin. >> >> ----- Original Message ----- >> *From:* Al Waschka <aw… [at] bellsouth.net> >> *To:* Ca… [at] yahoogroups.com >> *Sent:* Thursday, September 30, 2010 9:27 PM >> *Subject:* Re: [Cal_Boats] Serious battery question (Al) >> >> Sorry, I didn't see the other post. There are several alternatives. >> The most recommended one I have seen is to have three battery switches, two >> of them should be two position, i.e. ON/OFF. One ON/OFF switch is wired to >> the engine and to the starting battery. A third switch OFF/1/BOTH/2, is >> wired to the house loads and to two house batteries. The other ON/OFF >> switch is wired between the commons of the two other switches. Placing it >> in the ON position bridges the house and starting banks. It is recommended >> that this switch have a set of auxiliary contacts (field disconnect contacts >> would work here) that are used to sound an alarm when it is activated to >> remind you that you have the systems bridged and the house loads can bring >> down the starting battery. >> >> A variant of this is to use two cascaded OFF/1/BOTH/2 switches. Switch >> one common is connected to the engine, position one is connected to the >> starting battery, and position 2 is connected to the common of switch 2 >> which is also connected to the house loads. Positions 1 and 2 of switch 2 >> are connected to house batteries. This configuration is simpler, but it may >> be easier to get confused and run down the starting battery. In either >> case, only the battery connected to the engine gets charged when the engine >> is running unless you set both switches to both or have a battery combiner. >> This is the arrangement I'm thinking about to add a starting battery to my >> 33. Currently she has two house batteries on a single OFF/1/BOTH/2 switch. >> My setup (factory wiring) uses whatever is selected for all loads, starting >> and house. >> >> My experience with parallel batteries was years ago (wet cell lead/acid >> technology hasn't changed that much, I don't think) when GM used two >> batteries in parallel to start their HORRIBLE V-8 diesel engine that I got >> sucked into buying. Try as I might, I was never successful at replacing >> only one battery. With age, the fully charged voltage goes down and the >> internal resisance goes up, the net result is the newer battery works harder >> and degrades faster. When two batteries are in parallel, the one wth the >> higher level of charge will discharge into the other one to equalize charge, >> but the laws of physics dictate that half the energy in that exchange is >> lost. >> >> Hope this is helpful. >> >> Al >> >> >> --- On *Thu, 9/30/10, Allen Edwards <al… [at] PaloAltoPhoto.com>*wrote: >> >> >> From: Allen Edwards <al… [at] PaloAltoPhoto.com> >> Subject: Re: [Cal_Boats] Serious battery question (Al) >> To: Ca… [at] yahoogroups.com >> Date: Thursday, September 30, 2010, 11:42 PM >> >> >> I think you meant the other Al but I can chime in on the batteries. I >> think what he meant is that if a battery goes bad, dead, end of life, it may >> take the others it is connected in parallel with it. What I do with the 3 >> batteries I have on my motor home is always replace all 3 at the same time >> and wire them in parallel. But to answer the question asked, >> the alternative to wiring them in parallel is to have a battery selector >> switch. >> >> Allen >> also an old EE. >> >> On Thu, Sep 30, 2010 at 6:13 PM, <pw… [at] aol.com<http://us.mc1806.mail.yahoo.com/mc/compose?to=pw… [at] aol.com> >> > wrote: >> >> >> >> Al - >> >> Right now I have two 12-volt batties in parallel for starting my 56hp >> Yanmar and two 6-volt batteries in series for the house batteries. The boat >> was this way when I bought it. However, the house lights stay on no matter >> where the battery switch is. I've not conducted a test to see what all >> works and doesn't work when the switch is set to one or two, but with all >> the other wiring fiascos I've found I am assuming that I essentially have >> one big ass battery bank. My question to you however is in regard to your >> statement below about wiring the batteries in parallel and if done this way >> if one goes bad it takes out the other one. If you don't wire them this >> way, what is the other option? Keep 2 batteries but only connect one and >> keep the other as a spare and keep it charged in some manner? I hope to be >> re-wiring my boat soon and if there is a better option I'd love to hear it. >> >> Thanks - >> >> Paul West >> >> I'm also assuming that you would put the new house battery in parallel >> with the existing one, although I'm not convinced that is the best approach >> - in a parallel situation when one battery goes it usually takes the other >> with it so you end up having to change both batteries when one dies. >> >> >> > >

Yeah, I was talking about the unloaded situation. When the batteries are in parallel and not under load, charge will flow as required to equalize voltage. Energy will be lost in the internal resistances when this happens. Under charge, the terminal voltages will be the same, but due to variations in the internal resistance and leakage resistances, the batteries will attain diferent states of charge and thus different electrochemical voltages. When the charging current is removed, the difference in cell voltages due to different states of charge will cause an equalization and again, energy will be lost. As long as there is enough of a load on the batteries that all batteries are sourcing current, this will not happen, but this is not typical on most boats I suspect. Al --- On Fri, 10/1/10, Allen Edwards <al… [at] PaloAltoPhoto.com> wrote: From: Allen Edwards <al… [at] PaloAltoPhoto.com> Subject: Re: Oops, my bad was - Re: [Cal_Boats] Serious battery question (Al) To: Ca… [at] yahoogroups.com Date: Friday, October 1, 2010, 1:55 AM Glad you clarified that. I was about to go nuts. I knew about the capacitors (1/2 CV^2 and all that) but I was not sure how it related to batteries. When two batteries are in parallel, they will always be at the same voltage. There may be some charge transfer after the load is removed and they come back up to resting voltage but my mind explodes when I try and figure that out. "In situations where multiple batteries are connected in series, parallel or series/parallel, replacement batteries should be the same size, type and manufacturer (if possible). Age and usage level should be the same as the companion batteries. Do not put a new battery in a pack which is more than 6 months old or has more than 75 cycles. Either replace with all new or use a good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm I think that is the bottom line. If you run batteries in parallel or series, replace all of them when one needs replacing. This is another interesting reference http://www.yuasabatteries.com/pdfs/TechMan.pdf Allen On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net> wrote: Regarding the equalization of charge with two batteries in parallel, there is energy loss, but it is situation dependent. The half figure I was referring to is when charge is equalized on two capacitors. Al

If all the batteries in the bank are the same age and have had the same life by being wired permanently in parallel you should be fine. You just have to replace them all as a group but that isn't a bad idea anyway, just expensive. Same for series batteries but there the issue is that during discharge the weak cell can get reverse charged, which can be bad. Allen On Fri, Oct 1, 2010 at 8:42 AM, Al Waschka <aw… [at] bellsouth.net> wrote: > > > Yeah, I was talking about the unloaded situation. When the batteries are > in parallel and not under load, charge will flow as required to equalize > voltage. Energy will be lost in the internal resistances when this > happens. Under charge, the terminal voltages will be the same, but due to > variations in the internal resistance and leakage resistances, the batteries > will attain diferent states of charge and thus different electrochemical > voltages. When the charging current is removed, the difference in cell > voltages due to different states of charge will cause an equalization and > again, energy will be lost. As long as there is enough of a load on the > batteries that all batteries are sourcing current, this will not happen, but > this is not typical on most boats I suspect. > > Al > > > --- On *Fri, 10/1/10, Allen Edwards <al… [at] PaloAltoPhoto.com>*wrote: > > > From: Allen Edwards <al… [at] PaloAltoPhoto.com> > Subject: Re: Oops, my bad was - Re: [Cal_Boats] Serious battery question > (Al) > To: Ca… [at] yahoogroups.com > Date: Friday, October 1, 2010, 1:55 AM > > > Glad you clarified that. I was about to go nuts. I knew about the > capacitors (1/2 CV^2 and all that) but I was not sure how it related to > batteries. When two batteries are in parallel, they will always be at the > same voltage. There may be some charge transfer after the load is removed > and they come back up to resting voltage but my mind explodes when I try and > figure that out. > > > "In situations where multiple batteries are connected in series, parallel > or series/parallel, replacement batteries should be the same size, type and > manufacturer (if possible). Age and usage level should be the same as the > companion batteries. Do not put a new battery in a pack which is more than 6 > months old or has more than 75 cycles. Either replace with all new or use a > good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm > > I think that is the bottom line. If you run batteries in parallel or > series, replace all of them when one needs replacing. > > This is another interesting reference > http://www.yuasabatteries.com/pdfs/TechMan.pdf > > Allen > > On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net<http://us.mc1806.mail.yahoo.com/mc/compose?to=aw… [at] bellsouth.net> > > wrote: > > > > Regarding the equalization of charge with two batteries in parallel, there > is energy loss, but it is situation dependent. The half figure I was > referring to is when charge is equalized on two capacitors. > > Al > > > >

The other thing that can blow alternators is voltage kickbacks from electric motors starting. I blew out a number of them when an air compressor kicked on (air suspension). I rewired the alternator to isolate it from the motor and all is well. Allen On Fri, Oct 1, 2010 at 8:30 AM, Al Waschka <aw… [at] bellsouth.net> wrote: > > > Finn, > > I'm going to go with heat as the problem. If your alternator is relatively > new (design, that is) I don't think the alternator will put out any more > current into two (or three) batteries in parallel, it will just take longer > to charge the more batteries you have. So minimizing heat is really > important. I think you are on the right track. > > Al > --- On *Fri, 10/1/10, Fin Beven <fi… [at] msn.com>* wrote: > > > From: Fin Beven <fi… [at] msn.com> > Subject: Re: [Cal_Boats] Serious battery question (Al) > To: Ca… [at] yahoogroups.com > Date: Friday, October 1, 2010, 9:44 AM > > >  > To: Al, Allan, Tim, and everyone else who has tried to help ... > > First, thanks for all of your advice. > > The history of all this is my 2005 TransPac race. > > I did have 2 "4-D" batteries in parallel. Believing that charging was most > productive if the initial battery voltage was relatively low, we'd gone > nearly 24 hours without charging. We started up the engine just fine, and > turned on the water-maker. An hour later I looked at the Link 2000 > amp/volt meter and realized that we were not charging. We had a sat-phone > and were able to reach our engine mechanic. His assessment was that we > had blown the diodes on the alternator, and since it never occurred to me to > carry a spare alternator, nothing could be done. > > At the time, the alternator (and engine) were running in a relatively > small, confined engine box. I never determined exactly what it was caused > the diodes to blow. The two most likely culprits seemed to be either too > much heat, too much demand on the alternator caused by the two low > batteries, or some combination of the two. > > Obviously, my main goal here is to not repeat that blown diode situation > > Since then, I cut two big (6") holes in my engine box, one to the side, and > one to the rear of the alternator. This should really help with the > cooling-of-the-alternator issue. > > Al .. yes, I have a combiner. I don't see a problem there. The engine > starting battery is always connected to the alternator. Once the > alternator come up to charging voltage, the combiner "combines", and links > the house batteries to the alternator. > > From all that all of you have written, I'm inclined to add the additional > 4-D house battery, and hope that the extra cooling air around my alternator > will solve the problem. > > Again, thanks to all. > > Fin. > > ----- Original Message ----- > *From:* Al Waschka<http://us.mc1806.mail.yahoo.com/mc/compose?to=aw… [at] bellsouth.net> > *To:* Ca… [at] yahoogroups.com<http://us.mc1806.mail.yahoo.com/mc/compose?to=Ca… [at] yahoogroups.com> > *Sent:* Thursday, September 30, 2010 9:27 PM > *Subject:* Re: [Cal_Boats] Serious battery question (Al) > > Sorry, I didn't see the other post. There are several alternatives. > The most recommended one I have seen is to have three battery switches, two > of them should be two position, i.e. ON/OFF. One ON/OFF switch is wired to > the engine and to the starting battery. A third switch OFF/1/BOTH/2, is > wired to the house loads and to two house batteries. The other ON/OFF > switch is wired between the commons of the two other switches. Placing it > in the ON position bridges the house and starting banks. It is recommended > that this switch have a set of auxiliary contacts (field disconnect contacts > would work here) that are used to sound an alarm when it is activated to > remind you that you have the systems bridged and the house loads can bring > down the starting battery. > > A variant of this is to use two cascaded OFF/1/BOTH/2 switches. Switch one > common is connected to the engine, position one is connected to the starting > battery, and position 2 is connected to the common of switch 2 which is also > connected to the house loads. Positions 1 and 2 of switch 2 are connected > to house batteries. This configuration is simpler, but it may be easier to > get confused and run down the starting battery. In either case, only the > battery connected to the engine gets charged when the engine is running > unless you set both switches to both or have a battery combiner. This is > the arrangement I'm thinking about to add a starting battery to my 33. > Currently she has two house batteries on a single OFF/1/BOTH/2 switch. My > setup (factory wiring) uses whatever is selected for all loads, starting and > house. > > My experience with parallel batteries was years ago (wet cell lead/acid > technology hasn't changed that much, I don't think) when GM used two > batteries in parallel to start their HORRIBLE V-8 diesel engine that I got > sucked into buying. Try as I might, I was never successful at replacing > only one battery. With age, the fully charged voltage goes down and the > internal resisance goes up, the net result is the newer battery works harder > and degrades faster. When two batteries are in parallel, the one wth the > higher level of charge will discharge into the other one to equalize charge, > but the laws of physics dictate that half the energy in that exchange is > lost. > > Hope this is helpful. > > Al > > > --- On *Thu, 9/30/10, Allen Edwards <al… [at] PaloAltoPhoto.com>*wrote: > > > From: Allen Edwards <al… [at] PaloAltoPhoto.com> > Subject: Re: [Cal_Boats] Serious battery question (Al) > To: Ca… [at] yahoogroups.com > Date: Thursday, September 30, 2010, 11:42 PM > > > I think you meant the other Al but I can chime in on the batteries. I > think what he meant is that if a battery goes bad, dead, end of life, it may > take the others it is connected in parallel with it. What I do with the 3 > batteries I have on my motor home is always replace all 3 at the same time > and wire them in parallel. But to answer the question asked, > the alternative to wiring them in parallel is to have a battery selector > switch. > > Allen > also an old EE. > > On Thu, Sep 30, 2010 at 6:13 PM, <pw… [at] aol.com<http://us.mc1806.mail.yahoo.com/mc/compose?to=pw… [at] aol.com> > > wrote: > > > > Al - > > Right now I have two 12-volt batties in parallel for starting my 56hp > Yanmar and two 6-volt batteries in series for the house batteries. The boat > was this way when I bought it. However, the house lights stay on no matter > where the battery switch is. I've not conducted a test to see what all > works and doesn't work when the switch is set to one or two, but with all > the other wiring fiascos I've found I am assuming that I essentially have > one big ass battery bank. My question to you however is in regard to your > statement below about wiring the batteries in parallel and if done this way > if one goes bad it takes out the other one. If you don't wire them this > way, what is the other option? Keep 2 batteries but only connect one and > keep the other as a spare and keep it charged in some manner? I hope to be > re-wiring my boat soon and if there is a better option I'd love to hear it. > > Thanks - > > Paul West > > I'm also assuming that you would put the new house battery in parallel with > the existing one, although I'm not convinced that is the best approach - in > a parallel situation when one battery goes it usually takes the other with > it so you end up having to change both batteries when one dies. > > > >

Allen: So if my selector switch is 1 Both 2, when it is in both mode I know I am charging both batteries but I assume I have created the parallel connection you reference below. If I lose a battery does the "don't buy a new battery if......." that you have in quotes below apply. I guess yes. Bob Connell "Jollygood!", Cal 31, #59 Shilshole Bay, WA From: Allen Edwards <al… [at] PaloAltoPhoto.com> To: Ca… [at] yahoogroups.com Sent: Thu, September 30, 2010 10:55:41 PM Subject: Re: Oops, my bad was - Re: [Cal_Boats] Serious battery question (Al) Glad you clarified that. I was about to go nuts. I knew about the capacitors (1/2 CV^2 and all that) but I was not sure how it related to batteries. When two batteries are in parallel, they will always be at the same voltage. There may be some charge transfer after the load is removed and they come back up to resting voltage but my mind explodes when I try and figure that out. "In situations where multiple batteries are connected in series, parallel or series/parallel, replacement batteries should be the same size, type and manufacturer (if possible). Age and usage level should be the same as the companion batteries. Do not put a new battery in a pack which is more than 6 months old or has more than 75 cycles. Either replace with all new or use a good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm I think that is the bottom line. If you run batteries in parallel or series, replace all of them when one needs replacing. This is another interesting reference http://www.yuasabatteries.com/pdfs/TechMan.pdf Allen On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net> wrote: > >Regarding the equalization of charge with two batteries in parallel, there is >energy loss, but it is situation dependent. The half figure I was referring to >is when charge is equalized on two capacitors. > >Al

I'll give you my take. No. At least, No, most of the time. The parallel connection referred to is when the batteries are always connected in parallel. When you have your switch to BOTH and the engine running, the alternator is probably providing enough current to charge both batteries, but they will take different currents because they will likely not be at the same state of charge and are not matched. When the engine is off you should probably switch out of BOTH, maybe even before shutting the engine off, unless you have a failrly high load, several amps, like full running lights. That case is the reverse of the charging case. Both batteries will supply some current, but they will probably not be equal, again due to different state of charge. It's the in between case, not charging, light loads, where the battery with the higher state of charge will charge the other battery but energy will be lost in the process. In my opinion, as long as you get out of BOTH beore or soon after the engine stops, having unmatched batteries will not be a problem. I should also say,however, that switching batteries, particularly through OFF with the alternator running, may blow the diodes unless your battery switch has a set of auxiliary contacts wired to disconnect the field when no battery is across the alternator. My best guess (and my experience over the last 10 years with my boat is that going from BOTH to 1 or 2 is not a problem. Al --- On Fri, 10/1/10, Bob Connell <jo… [at] yahoo.com> wrote: From: Bob Connell <jo… [at] yahoo.com> Subject: Re: Oops, my bad was - Re: [Cal_Boats] Another Serious battery question (Al) To: Ca… [at] yahoogroups.com Date: Friday, October 1, 2010, 9:25 PM Allen: So if my selector switch is 1 Both 2, when it is in both mode I know I am charging both batteries but I assume I have created the parallel connection you reference below. If I lose a battery does the "don't buy a new battery if......." that you have in quotes below apply. I guess yes. Bob Connell "Jollygood!", Cal 31, #59 Shilshole Bay, WA From: Allen Edwards <al… [at] PaloAltoPhoto.com> To: Ca… [at] yahoogroups.com Sent: Thu, September 30, 2010 10:55:41 PM Subject: Re: Oops, my bad was - Re: [Cal_Boats] Serious battery question (Al) Glad you clarified that. I was about to go nuts. I knew about the capacitors (1/2 CV^2 and all that) but I was not sure how it related to batteries. When two batteries are in parallel, they will always be at the same voltage. There may be some charge transfer after the load is removed and they come back up to resting voltage but my mind explodes when I try and figure that out. "In situations where multiple batteries are connected in series, parallel or series/parallel, replacement batteries should be the same size, type and manufacturer (if possible). Age and usage level should be the same as the companion batteries. Do not put a new battery in a pack which is more than 6 months old or has more than 75 cycles. Either replace with all new or use a good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm I think that is the bottom line. If you run batteries in parallel or series, replace all of them when one needs replacing. This is another interesting reference http://www.yuasabatteries.com/pdfs/TechMan.pdf Allen On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net> wrote: Regarding the equalization of charge with two batteries in parallel, there is energy loss, but it is situation dependent. The half figure I was referring to is when charge is equalized on two capacitors. Al

No. In this case you have two independent batteries that are not always connected. You put them in "both" to charge them and I assume then select either 1 or 2 to discharge so they are not seeing the same charge-discharge cycle. I am talking about batteries that are connected by battery cables so they are always connected Allen On Fri, Oct 1, 2010 at 6:25 PM, Bob Connell <jo… [at] yahoo.com>wrote: > > > Allen: So if my selector switch is 1 Both 2, when it is in both mode I > know I am charging both batteries but I assume I have created the parallel > connection you reference below. If I lose a battery does the "don't buy a > new battery if......." that you have in quotes below apply. I guess yes. > > Bob Connell > "Jollygood!", Cal 31, #59 > Shilshole Bay, WA > > > ------------------------------ > *From:* Allen Edwards <al… [at] PaloAltoPhoto.com> > *To:* Ca… [at] yahoogroups.com > *Sent:* Thu, September 30, 2010 10:55:41 PM > *Subject:* Re: Oops, my bad was - Re: [Cal_Boats] Serious battery question > (Al) > > > > Glad you clarified that. I was about to go nuts. I knew about the > capacitors (1/2 CV^2 and all that) but I was not sure how it related to > batteries. When two batteries are in parallel, they will always be at the > same voltage. There may be some charge transfer after the load is removed > and they come back up to resting voltage but my mind explodes when I try and > figure that out. > > > "In situations where multiple batteries are connected in series, parallel > or series/parallel, replacement batteries should be the same size, type and > manufacturer (if possible). Age and usage level should be the same as the > companion batteries. Do not put a new battery in a pack which is more than 6 > months old or has more than 75 cycles. Either replace with all new or use a > good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm > > I think that is the bottom line. If you run batteries in parallel or > series, replace all of them when one needs replacing. > > This is another interesting reference > http://www.yuasabatteries.com/pdfs/TechMan.pdf > > Allen > > On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net>wrote: > >> >> >> >> Regarding the equalization of charge with two batteries in parallel, there >> is energy loss, but it is situation dependent. The half figure I was >> referring to is when charge is equalized on two capacitors. >> >> Al >> >> > > >

Don't change the switch position with the motor running unless the switch has a field connection. It may be ok, but it may blow things up. You could try it and let us know (just kidding). You can leave the switch in "both" for a long time without damaging the batteries. By long time I mean like I forgot and left it there all weekend. As long as you don't make a habit of it you should be OK. Allen On Fri, Oct 1, 2010 at 7:35 PM, Al Waschka <aw… [at] bellsouth.net> wrote: > > > I'll give you my take. No. At least, No, most of the time. The parallel > connection referred to is when the batteries are always connected in > parallel. When you have your switch to BOTH and the engine running, the > alternator is probably providing enough current to charge both batteries, > but they will take different currents because they will likely not be at the > same state of charge and are not matched. When the engine is off you should > probably switch out of BOTH, maybe even before shutting the engine off, > unless you have a failrly high load, several amps, like full running > lights. That case is the reverse of the charging case. Both batteries will > supply some current, but they will probably not be equal, again due to > different state of charge. It's the in between case, not charging, light > loads, where the battery with the higher state of charge will charge the > other battery but energy will be lost in the process. In my opinion, as > long as you get out of BOTH beore or soon after the engine stops, > having unmatched batteries will not be a problem. I should also > say,however, that switching batteries, particularly through OFF with the > alternator running, may blow the diodes unless your battery switch has a set > of auxiliary contacts wired to disconnect the field when no battery is > across the alternator. My best guess (and my experience over the last 10 > years with my boat is that going from BOTH to 1 or 2 is not a problem. > > Al > > > --- On *Fri, 10/1/10, Bob Connell <jo… [at] yahoo.com>* wrote: > > > From: Bob Connell <jo… [at] yahoo.com> > Subject: Re: Oops, my bad was - Re: [Cal_Boats] Another Serious battery > question (Al) > > To: Ca… [at] yahoogroups.com > Date: Friday, October 1, 2010, 9:25 PM > > > > Allen: So if my selector switch is 1 Both 2, when it is in both mode I > know I am charging both batteries but I assume I have created the parallel > connection you reference below. If I lose a battery does the "don't buy a > new battery if......." that you have in quotes below apply. I guess yes. > > Bob Connell > "Jollygood!", Cal 31, #59 > Shilshole Bay, WA > > > ------------------------------ > *From:* Allen Edwards <al… [at] PaloAltoPhoto.com> > *To:* Ca… [at] yahoogroups.com > *Sent:* Thu, September 30, 2010 10:55:41 PM > *Subject:* Re: Oops, my bad was - Re: [Cal_Boats] Serious battery question > (Al) > > > Glad you clarified that. I was about to go nuts. I knew about the > capacitors (1/2 CV^2 and all that) but I was not sure how it related to > batteries. When two batteries are in parallel, they will always be at the > same voltage. There may be some charge transfer after the load is removed > and they come back up to resting voltage but my mind explodes when I try and > figure that out. > > > "In situations where multiple batteries are connected in series, parallel > or series/parallel, replacement batteries should be the same size, type and > manufacturer (if possible). Age and usage level should be the same as the > companion batteries. Do not put a new battery in a pack which is more than 6 > months old or has more than 75 cycles. Either replace with all new or use a > good used battery." http://www.windsun.com/Batteries/Battery_FAQ.htm > > I think that is the bottom line. If you run batteries in parallel or > series, replace all of them when one needs replacing. > > This is another interesting reference > http://www.yuasabatteries.com/pdfs/TechMan.pdf > > Allen > > On Thu, Sep 30, 2010 at 9:32 PM, Al Waschka <aw… [at] bellsouth.net<http://us.mc1806.mail.yahoo.com/mc/compose?to=aw… [at] bellsouth.net> > > wrote: > > > > Regarding the equalization of charge with two batteries in parallel, there > is energy loss, but it is situation dependent. The half figure I was > referring to is when charge is equalized on two capacitors. > > Al > > > > >