Battery bank charging amps?? Do I need to limit voltage??

[justinbeaird]

If I have a MPPT charge controller and one AGM SLA battery rated at 30amp max charge rate do I need to limit charge rate? Or do MPPT have an algorithm that can test for best charge rate??

Also If I upgrade to 2 AGM SLA batteries in parallel, and they are both rated for 30amp max charge current can I charge them a little under 60 amp or do I have to charge the whole battery bank under 30 amp??

 

[Diysolar123]

you should set the limit for the safety of your batteries.
If you put two batteries in parallel then you can double the amount of current the battery "pack" can take (and provide); do make sure to individually charge both to the same level before you connect them in parallel.

 

[MichaelK]

Well, it depends. How much solar do you have? One 100W panel would only theoretically put out 7.7Amps, so exceeding 30A would be irrelevant. To exceed 30A you would need at least 30A X 13Vcharging = 390W, and assuming your panels never put out 100%, it's more likely to need 460W to exceed 30.

My controller can be set to limit amps, and I have. What unit do you have? As DS123 states, you double the battery, and you double the maximal amps.

 

[justinbeaird]

Well, it depends. How much solar do you have? One 100W panel would only theoretically put out 7.7Amps, so exceeding 30A would be irrelevant. To exceed 30A you would need at least 30A X 13Vcharging = 390W, and assuming your panels never put out 100%, it's more likely to need 460W to exceed 30.

My controller can be set to limit amps, and I have. What unit do you have? As DS123 states, you double the battery, and you double the maximal amps.

1,000w@24v 2P5S 60A MPPT..

 

[DerpsyDoodler]

1,000w@24v 2P5S 60A MPPT..

limit your scc output until you get the other battery installed. even then, if you have to take a battery offline for some reason, don't forget to limit the charge again, until both are installed back in parallel.

 

[MichaelK]

2P5S 60A MPPT..

This really doesn't tell me anything. What's the brand name?

Assuming your array puts out (1000W/25Vcharging) X 0.85fudgefactor = 34A. Not really that high over the limit. I'd guess that on most days, your battery might be fully charged and floating before maximal amperage gets produced.

Or, did you mean those are 24V panels? If it's one 100Ah 12V battery, then the math is (1000W/13Vcharging) X 0.85FF =65A. Yeah, way over.