BATTERY CHARGING PUZZLE?

[Oasisbob]

In charging my twin group 27 deep cycle lead acid batteries wired together to produce 12 volts (called series?) if I charge at 15 amps am I really charging both at 7.5 amps? Or are they both charging at 15 amps? BTW I got an astonishing nine years out of my last set of Costco interstate batteries. I had a load test performed on the deceased and one rated good, the other was toast as I mistakenly set the smart charger to charge at 40 amps.

[grizzzman]

Almot wrote:
Series. Daisy chain. What climbs from one end, comes off the other end. 15A it is. What puzzle?

You have group 27 batteries (2)? That would be a 24 volt system in series? Parallel is 2 12 volt batteries at 12 volts

[time2roll]

Yes the charger rating will be split between the two 12v batteries connected in parallel. 15 amps charger becomes 7.5 amps each battery.

BTW 40 amps will not hurt the batteries either. (20 amps each).

[grizzzman]

Oasisbob wrote:
In charging my twin group 27 deep cycle lead acid batteries wired together to produce 12 volts (called series?) if I charge at 15 amps am I really charging both at 7.5 amps? Or are they both charging at 15 amps? BTW I got an astonishing nine years out of my last set of Costco interstate batteries. I had a load test performed on the deceased and one rated good, the other was toast as I mistakenly set the smart charger to charge at 40 amps.

The answer is "depends" in a perfect world both would receive 7.50amps....... The way the batteries are wired play a large role on charge and discharge behavior. Here is some homework if you are interested.Good stuff here

[Almot]

Series. Daisy chain. What climbs from one end, comes off the other end. 15A it is. What puzzle?

[JamesJudasPries]

Are you sure you have group 27 batteries? Those are 12 volt batteries, so two of them wired in parallel is the only way to properly connect them. That is, positive to positive and negative to negative. This connection method provides 12 volts, but gives you the amp hour capacity of both batteries combined, so about 105 amp hours x2 = 210 amp hours, 12 volt.

If you had 2 x 6 volt golf cart batteries, you must connect them in series (one positive terminal going to other battery's negative terminal, the remaining terminal of each battery being pos and neg. Their voltages combine to become 12v, but the amp hours will only be that of a single battery (220 amp hours).

Google search battery series / parallel connections for a good picture or two.


To answer your question, yes if you have a parallel battery setup each battery will see about half the rated current of the charger.

If you had a series system with 6v golf cart batteries, then the current would be the rated current through both.

[RJsfishin]

That is wired in parallel.
And yes,7,5 amps per battery.
And 40 amp setting won't hurt 2 27 DC batteries

[Lwiddis]

What does the battery manufacturer recommend for charging voltage?