Bob B
Emperor Of Solar
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- Sep 21, 2019
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The BMS will have to be sized for the peak amp draw.
Urgent advice needed
- Thread starter alanb
- Start date
The BMS will have to be sized for the peak amp draw.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
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- 20,806
25 kWh/day or about 40A average draw from 48V battery.
But what is the maximum short-term surge draw going to be? Maximum sustained draw? That's what current the BMS had to handle.
May as well order 16x 280 cells and get on with it. A 100 amp BMS will easily give you 4500 watts.
https://overkillsolar.com/product-category/48v-bms/
I just went through this on a smaller scale with an op that couldn't charge past 13.1v.
diysolarforum.com
Even though we were all telling him that is the normal resting voltage etc etc. Turns out the manufacturer had an early model of No-Series-Connection bms, and when hooked in series, blew the bms, but no so badly it was totally fried. But just screwed up enough that the battery won't charge past 13.1, most likely tripping out on a totally unbalanced interior bank due to the smoked - but not fried, bms.
Always the chance that resellers might be pawning off these drop-ins with damaged bms, because a casual inspection with a voltmeter, or helpful advice from us that this is just a "settled voltage", hides the true nature of the problem that the bms wasn't designed for series-connections.
LiFePo4 max out at 13v. Have I been hosed?
I have 3 of these. I've tried solar charging and Renogy Lifepo4 charger and these batteries only charge to 13.0, 13.1, 13.2 volts. Is this okay or have I been hosed? https://www.amazon.ca/dp/B09JFTDBK4/?coliid=I12WB2L337ZLXE&colid=Y2JRCZRGTMLC&ref_=lv_ov_lig_dp_it&th=1
diysolarforum.com
Even though we were all telling him that is the normal resting voltage etc etc. Turns out the manufacturer had an early model of No-Series-Connection bms, and when hooked in series, blew the bms, but no so badly it was totally fried. But just screwed up enough that the battery won't charge past 13.1, most likely tripping out on a totally unbalanced interior bank due to the smoked - but not fried, bms.
Always the chance that resellers might be pawning off these drop-ins with damaged bms, because a casual inspection with a voltmeter, or helpful advice from us that this is just a "settled voltage", hides the true nature of the problem that the bms wasn't designed for series-connections.
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