diy solar

diy solar

Please I need help with set up systems

omsmall

New Member
Joined
Dec 31, 2019
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Good day,please I need your contributions, in recent systems built, I actually have set up of 44pcs solar arrays of 250w each, and am using my two hybrid inverter charger, that accept 6.6kw each from the arrays and I parralel the two machines. This systems was only used during day because the hybrid inverters are battery and works without battery,it's powers appliances for only day time which is what is needed for only.. 22panels goes to inverter A, another 22 panels goes to inverter B....and this two inverters are parraleled together...... But currently I decided to make a DIY lifep04 battery of 16S of 280ah 3.2v, making it about 14.5kwh battery....... Now am in a confused state as to which Daly Bms that could accept the total arrays coming to charge the batteries..... Please I need your opinion brothers and sisters
 
44 * 250W = 11,000W

11,000W/51.2V = 215A

I would select a BMS capable of 250A CHARGING. Not that some BMS have different ratings: 100% for discharge and 50% for charge.

DALY reputation is not so good here. Many recent reported BMS failures.
 
I actually have set up of 44pcs solar arrays of 250w each
11,000W/51.2V = 215A
This is a LOT of amps for that battery. This might be a good candidate for pointing some of the array east-ish, some south and some west-ish to spread the charging out over the daylight hours. So it might charge more like 110A for 10 hours (rough numbers) instead of 215A for 5 hours.

280Ah x 51.2V = 14,336Wh
14,336Wh / 11,000 solar = 1.3 hours to recharge from empty.

What are your energy use patterns?
 
This is a LOT of amps for that battery. This might be a good candidate for pointing some of the array east-ish, some south and some west-ish to spread the charging out over the daylight hours. So it might charge more like 110A for 10 hours (rough numbers) instead of 215A for 5 hours.

280Ah x 51.2V = 14,336Wh
14,336Wh / 11,000 solar = 1.3 hours to recharge from empty.

What are your energy use patterns?

Good catch. I missed that.
 
But currently I decided to make a DIY lifep04 battery of 16S of 280ah 3.2v, making it about 14.5kwh battery
14,336Wh / 11,000 solar = 1.3 hours to recharge from empty.
I meant to point out that your system has a disproportionate amount of solar to battery so a second battery (or more) could be charged by solar on a daily basis.
This would also spread your charging amps across batteries so you could get by with smaller (more reasonable and more reasonably priced) BMSs.

Otherwise, as you propose, you could throttle your solar charging by limiting charging amps to match whatever BMS you choose. Charging a 280Ah battery at 215A is mighty aggressive (and possibly dangerous). And, you will get a MUCH better charge at a lower charge rate: i'd shoot for as low as possible to reach full charge during solar hours.
 
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