I have a pair of 6v 420ah flooded batteries connected in series with a 30a MPPT epever and 700w of solar. Right now my MPPT is maxing out at charging the batteries at 30 amp. I was told going up to 40 amps MPPT was going to charge the battery too quick and require to have more battery maintenance. Is this correct? What is the recommended charge amps
Charge amperage
- Thread starter Simonbr2
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Welcome to the forum.
Specifications vary, but the guideline is about 0.1C or 42A in your case. Given that solar rarely outputs peak power, and it definitely doesn't do it first thing in the morning, targeting something closer to 0.15C is probably more advantageous. That would put you at 63A.
It is absolutely best to check with the battery manufacturer.
Your array is capable of: 700W/12V = 58A
You are over-paneled by almost 100%.
Specifications vary, but the guideline is about 0.1C or 42A in your case. Given that solar rarely outputs peak power, and it definitely doesn't do it first thing in the morning, targeting something closer to 0.15C is probably more advantageous. That would put you at 63A.
It is absolutely best to check with the battery manufacturer.
Your array is capable of: 700W/12V = 58A
You are over-paneled by almost 100%.
Hello Snoobler,
Just to make sure I understand, the guideline for the amount of amp to charge with is to multiply the 0.1C by the Ah (or up to 0.15C)? Is this harder on the flooded batteries (diminish charge cycle, more boiling and loss of water). The batteries I have are the Interstate 903-S and searching their site I believe the model is L-16HCL but I cannot find any datasheet.
The reason for the over-panels was to have the system pull in more watts for the charge controller even on overcast days.
Just to make sure I understand, the guideline for the amount of amp to charge with is to multiply the 0.1C by the Ah (or up to 0.15C)? Is this harder on the flooded batteries (diminish charge cycle, more boiling and loss of water). The batteries I have are the Interstate 903-S and searching their site I believe the model is L-16HCL but I cannot find any datasheet.
The reason for the over-panels was to have the system pull in more watts for the charge controller even on overcast days.
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Lead-acid in general and FLA in particular have a relatively narrow charge "window." In addition to an upper limit, you don't want to charge below about 0.05C as that can encourage sulfidation during charge.
It also depends on your use/charge profile. If you're using loads in the morning, OR you don't use that much battery overnight, and the battery quickly charges to full in the morning, it's not likely to see peak current anyway.
Another consideration is powering loads with solar once battery is in float. If you have the potential for 700W, but you can only put-out 400W due to SCC limitations. you're wasting a lot of solar when you could otherwise use it for loads.
It's not uncommon to over-panel. It seems a bit uncommon to over-panel by nearly 2X.
It also depends on your use/charge profile. If you're using loads in the morning, OR you don't use that much battery overnight, and the battery quickly charges to full in the morning, it's not likely to see peak current anyway.
Another consideration is powering loads with solar once battery is in float. If you have the potential for 700W, but you can only put-out 400W due to SCC limitations. you're wasting a lot of solar when you could otherwise use it for loads.
It's not uncommon to over-panel. It seems a bit uncommon to over-panel by nearly 2X.
