Solar charging

I installed a solar panel today. My boat has two batteries, wired in parallel, so I attached the positive connector to battery 1 positive and the negative to battery 2 negative. Should just act as one 12 volt battery. As I remember my electric shop course in HS. In parallel voltage is the same. In series currant adds. David Cal29 411

Not quite, David. In parallel - current adds; in series - voltage adds. Cheers Charlie Annapolis From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] Sent: Sunday, July 08, 2018 10:28 PM To: Yahoogroups <ca… [at] yahoogroups.com> Subject: [Cal_Boats] Solar charging I installed a solar panel today. My boat has two batteries, wired in parallel, so I attached the positive connector to battery 1 positive and the negative to battery 2 negative. Should just act as one 12 volt battery. As I remember my electric shop course in HS. In parallel voltage is the same. In series currant adds. David Cal29 411

Batteries in parallel the voltages are equal. Total voltage of 12v batteries in parallel is always 12v. Branch current, the current through each battery, is dependent on the batteries internal resistance and could be different through each battery. Series batteries add together.... 12v+12v+.....= 12v (number of batteries) Current flow is the same though through each battery. The cable leads are common. On Jul 8, 2018 19:27, "david dobbs tm… [at] yahoo.com [Cal_Boats]" <Ca… [at] yahoogroups.com> wrote: I installed a solar panel today. My boat has two batteries, wired in parallel, so I attached the positive connector to battery 1 positive and the negative to battery 2 negative. Should just act as one 12 volt battery. As I remember my electric shop course in HS. In parallel voltage is the same. In series currant adds. David Cal29 411

On 7/9/2018 2:47 AM, David Seltzer dp… [at] yahoo.com [Cal_Boats] wrote: > > > Batteries in parallel the voltages are equal. > Total voltage of 12v batteries in parallel is always 12v. Branch > current, the current through each battery, is dependent on the > batteries internal resistance and could be different through each battery. > > Series batteries add together.... > 12v+12v+.....= 12v (number of batteries) > > Current flow is the same though through each battery. The cable leads > are common. OK, as a one-battery guy who's never had to think about it too much, this raises a question. If the current flow can be unequal in paralleled 12 V batteries but is equal (obviously) in series batteries, is that why it's more common to use 6V batteries in series than 12V batteries in parallel? Chris Campbell > >

Chris, I would say your reason is a good one for the 6V batteries in series. We also need to keep in mind that the individual cells in a battery are also not identical. They are (almost) always connected in series. In a parallel battery construction, the higher voltage battery drains current first until its voltage gets down to the level of the second battery. The work sharing is thus not even, nor is the charging cycle. As an aside, we are now seeing more systems going to 24 volts. For the same power output (current x voltage), the current required is half that of the 12 volt battery. The voltage drop in wiring resistance at 24 volts is half as much as for a 12 volt battery. This is also the reason that cars went from 6VDC to 12VDC early on. Take Care Charlie Annapolis Single Battery guy in the Cal 25 From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] Sent: Monday, July 09, 2018 9:16 AM To: Ca… [at] yahoogroups.com; David Seltzer <dp… [at] yahoo.com> Subject: Re: [Cal_Boats] Solar charging On 7/9/2018 2:47 AM, David Seltzer dp… [at] yahoo.com <mailto:dp… [at] yahoo.com> [Cal_Boats] wrote: Batteries in parallel the voltages are equal. Total voltage of 12v batteries in parallel is always 12v. Branch current, the current through each battery, is dependent on the batteries internal resistance and could be different through each battery. Series batteries add together.... 12v+12v+.....= 12v (number of batteries) Current flow is the same though through each battery. The cable leads are common. OK, as a one-battery guy who's never had to think about it too much, this raises a question. If the current flow can be unequal in paralleled 12 V batteries but is equal (obviously) in series batteries, is that why it's more common to use 6V batteries in series than 12V batteries in parallel? Chris Campbell

Remember the load always sets the total current flow so in series what goes through one battery goes through any others. Battery installs depend on application, loading and duration of use requirements. Maybe physical size is a factor? The amp-hour capacity of two 6v may be better for your needs than one 12v. But, With two 6v you are able to tap a 6v feed if necessary. On Jul 9, 2018 06:15, "ccampbell cc… [at] lsnm.org [Cal_Boats]" <Ca… [at] yahoogroups.com> wrote: On 7/9/2018 2:47 AM, David Seltzer dp… [at] yahoo.com [Cal_Boats] wrote: Batteries in parallel the voltages are equal. Total voltage of 12v batteries in parallel is always 12v. Branch current, the current through each battery, is dependent on the batteries internal resistance and could be different through each battery. Series batteries add together.... 12v+12v+.....= 12v (number of batteries) Current flow is the same though through each battery. The cable leads are common. OK, as a one-battery guy who's never had to think about it too much, this raises a question. If the current flow can be unequal in paralleled 12 V batteries but is equal (obviously) in series batteries, is that why it's more common to use 6V batteries in series than 12V batteries in parallel? Chris Campbell

Dont forget an isolator / smart charger between th solar panels and the batteries. When you start the motor the alternator can fry the panels. Also it will shut off the solar charging once the batteries are full. West marine or harbor freight

Not to worry, the panel is made by Coleman, came with a controller. I don't plan to leave it installed, just when I'm away from the boat. Cost around $90 on Amazon.David On Monday, July 9, 2018, 9:04:09 AM CDT, bl… [at] sbcglobal.net [Cal_Boats] <Ca… [at] yahoogroups.com> wrote: Dont forget an isolator / smart charger between th solar panels and the batteries. When you start the motor the alternator can fry the panels. Also it will shut off the solar charging once the batteries are full. West marine or harbor freight