Battery charging max current

fca1fca1 Solar Expert Posts: 124 ✭✭
Hi I have a 2 battery banks in parallel each with 12 exide epzv 255ah c5 forklift batts
Total 510ah at c5 .
Now I have a 1760w of pv and will add next month more 3000w
So in raw I will have 4760w that will all the losts will probably reach to batts 70% of that ~33000w
So I will have 3300/24v =138amps charge capacity...
Meaning I will charge bats ~C4 of their capacity (510ah at C5) and maybe c5 at their c20 capacity...
Too high charge rate for summer....

The idea is having enough pv to winter and also use heavy loads during sun hours so maybe these high charge rates wil happen only a few times ..,


Thoughts, suggestion ( beside buying a bigger battery bank ;) )
Midnite 150 classic will allow to control the max charge rate ? I think so ...
Regards

Comments

  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery charging max current
    fca1 wrote: »
    So I will have 3300/24v =138amps charge capacity...
    <snip>
    Midnite 150 classic will allow to control the max charge rate ? I think so ...

    Yes, the Classic can limit its charge rate. But you will need more than one classic to handle your expanded solar array.

    I don't know how midnite coordinates charge limits when there is more than one classic.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • fca1fca1 Solar Expert Posts: 124 ✭✭
    Re: Battery charging max current

    We will be a new midnite and my existing tristar mppt 60
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Battery charging max current
    fca1 wrote: »
    We will be a new midnite and my existing tristar mppt 60

    I don't know how you will be able to limit the charge rate during bulk charging:
    http://forum.solar-electric.com/showthread.php?17716

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Battery charging max current

    What I have learned about high current charging is that during Bulk the batteries will not care how much current you throw at them. The way I set up my multiple charging sources is to let one be the master absorbing source. I set it about .050-1 volt higher or more than the others. Once they all reach ( say 28.4 ) the lower ones will go into absorb because the higher one will drive them with it's higher voltage. The lower ones are faked out thinking the battery will not accept any more current and start to limit their output.

    You also need to be using the bank, if your not pulling down to 60 % SOC or so then you will have way to much current. The most talked about current limit on deep cycle batteries is to not have more current than to amount of amps hrs you need to return. I Bulk at @ 25 % ( 250 amps ) on many 1000 amp hr banks, but they are at 50-60 % SOC. Yes, you have high current, but it's spread over many cells.

    You need to watch the cell temperatures when you start using the set up, you'll get very little rise in Bulk, that only comes in absorb.
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