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diy solar

EVE 105 48v 2p16s build

ChrisG said:
Voltage sag, under load my voltage drops more than it should as I noted above to where the inverter thinks it needs a charge cycle.

Before pulling the pack completely apart I’m going to connect the two 16 cell sets in the back of the picture with 2/0 cable with tinned lugs vs the bus bars. If I put a plastic level over the cells connecting both sets it seems the weight of the batteries on the shelf is causing a dip in the center causing the two sides not to be level.
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I haven't load too much (just 1100W continuous testing but I haven't noted too much voltage drop under load. I will test again to give you numbers.
 
For me at 3000 AC watts I sagged about 2.5 volts. At 5500 watts pack lost about 2.9volts.
 
Well, little better using a cable instead of busbars connecting sides of pack. Floated at 53.3v for a bit then turned on mini split for heat. Still not happy with it. Think the best method is splitting the 32 cells into 2 16 cell packs with their own BMS. Whatever was wrong with the wire resistance on cell 16 is gone now also.
 

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ChrisG said:
Well, little better using a cable instead of busbars connecting sides of pack. Floated at 53.3v for a bit then turned on mini split for heat. Still not happy with it. Think the best method is splitting the 32 cells into 2 16 cell packs with their own BMS. Whatever was wrong with the wire resistance on cell 16 is gone now also.
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Maybe using 2 bus bars stacks? I like the idea of 2 AWG cables. I order 10FT to match my BMS. I have a Daly 250 and also a JK 150 coming tomorrow. I want to test both.
 
Not noticing any heat but a general question about the JK 200amp BMS P- and B- wires. There are two 7awg which totals up to ~24mm2 which equals 4awg. Even with less than a 1 ft run, isn’t 4awg way to small for pulling 200a?

BMS running pack: JK B2A20S20P BMS 2A BALANCE CURRENT BMS 200A
 
I personally will not trust more than 100A on a 4 AWG wire. I love my 2 AWG connections.
 
Ah. Larger wire because you’re running 24v vs my 48v.
It’s working better than yesterday but still think going to change from 2p16s to 16s2p and run two JK BMS with 600amp busbars connecting the packs.
 
ChrisG said:
Ah. Larger wire because you’re running 24v vs my 48v.
It’s working better than yesterday but still think going to change from 2p16s to 16s2p and run two JK BMS with 600amp busbars connecting the packs.
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Post numbers with that change. I may go in the same route once upgrade.
 
ChrisG said:
Ah. Larger wire because you’re running 24v vs my 48v.
It’s working better than yesterday but still think going to change from 2p16s to 16s2p and run two JK BMS with 600amp busbars connecting the packs.
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IT will be similar to mine: Two 16S S168 (55AH) and one 16S EVE 105. The S168s are two years old and the EVE is one year old. Each pack uses JK BMS.3 Racks.jpg
 
The nice part of parallel 2P16S even with different AH packs still runs + add redundancy. I like the Idea.
 
After fully charge the pack, Tested with a 1150W load for about 15 minutes and here are the numbers while working.

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Your measurements seem more in line with my second test using the 1/0 to join both sides of the pack.

48v battery 2p16s 32 Eve 105ah cells in 1 pack Full Charge:
  • Using busbar to connect 16/16 cells: 46a/3.16v
  • Using 1/0 Cable to connect 16/16 cells: 68a/3.281v
Under your load you were in the 3.24 range.
 
Forgot add this ones
 

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More testing today. In theory for the EVE105, a pack of 2p16s or 16s2p could output 200amps @ 48v nominal max continuous or 100amp normal continuous. Well pump (Grundfos SQ) is the major hit with 23a on top of the 10a already being pulled here in the graphs. Maybe I'm over thinking this but seems the voltage sag should be less than the .9v drop in the overall pack seen below.

1708045974197.png
 
What’s the state of charge during that test? 3.29 isn’t known to be in the supper meat of the SOC curve.
 
740GLE said:
What’s the state of charge during that test? 3.29 isn’t known to be in the supper meat of the SOC curve.
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@740GLE SOC isn't reported as frequently as other measurements but between the two reported points in that time range seems to be about 85%
1708051279897.png
 
But how is SOC calculated just the charger? Or via a shunt?

I guess if the cells were at resting voltage of more like 3.35-3.4v then a load applied it’d be interesting to see what the sag was.
 
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