Charging amp question

[OffGridCostaRica]

Newbie here and I searched this question and can’t seem to find an answer. Sorry if it’s been posted or is simple knowledge.

I have 16, 12v 200ah gel batteries wired in 4 quadrants to essentially give me 4x 48v 200ah batteries. Or 800ah of 48v batteries.

In the battery manual it states max charge amperage is 50amps… but that’s for the single 12v 200ah battery. My question is if that changes being in series to make 48V and 800ah total, or if my battery banks max charge amperage is 50amps because that’s all a single battery is recommended to handle.

Thanks!

 

[sunshine_eggo]

50A per 12V, 24V or 48V string, so you have a theoretical maximum of 200A into the 4 strings.

This assumes the batteries are perfectly sharing the load, and your wiring is top notch.

I would limit it to about 160A until you can verify that each string of batteries receives no more than 50A measured with a clamp DC ammeter.

 

[LakeHouse]

Newbie here and I searched this question and can’t seem to find an answer. Sorry if it’s been posted or is simple knowledge.

I have 16, 12v 200ah gel batteries wired in 4 quadrants to essentially give me 4x 48v 200ah batteries. Or 800ah of 48v batteries.

In the battery manual it states max charge amperage is 50amps… but that’s for the single 12v 200ah battery. My question is if that changes being in series to make 48V and 800ah total, or if my battery banks max charge amperage is 50amps because that’s all a single battery is recommended to handle.

Thanks!

The 50 Amp limit would be the most you’d want to push through a single battery. Since a series string all gets the same current, a single one of your 48V strings should have a maximum of 50 Amps charging.
You have 4 of those strings in parallel, and each one could take 50 Amps charging. In a perfect world 50 x 4 = 200 Amps would be your max charge current. But in a real world, the four battery sets won’t be exactly the same and so won’t exactly equally share the charge current. Your 200 Amps might actually look like 40+50+60+50 = 200, which would charge one string too quickly.
I’d leave some buffer in there. I’d limit charging to 100-150 Amps, and do some testing during a charge to ensure that none of strings are seeing more than 50 Amps. You could then adjust up (or down) based on that result.

 

[OffGridCostaRica]

Thank you guys much appreciated for the quick reply. Ive set it to 80 amps currently so ima leave it there and see if that’s enough for my needs.
Thanks!

 

[Mattb4]

The battery spec shows 20a as recommended charge rate for 1 battery. This is the rate you should attempt to charge at and not the Max. But since you have 4 strings in parallel that makes 80a and that is what you are using.

 

[OffGridCostaRica]

The battery spec shows 20a as recommended charge rate for 1 battery. This is the rate you should attempt to charge at and not the Max. But since you have 4 strings in parallel that makes 80a and that is what you are using.

Yes thank you that’s why I started with 80 amps and see if I get a decent charge rate/battery capacity throughout a day of sun and how long it takes to reach full with my daily usage.
Appreciate the help.