EG4 Generation 2 Batteries

Hi,
I have a whole house system I am still working out the details, and ran into a issue with one of my batteries. I have 12 EG4 batteries and a 12KW Growatt Inverter. Ten of the Twelve batteries are GEN2 with a display. One the last three I purchased back in July I noticed that one of them consistently is 5% or more lower than the rest when charging. I have observed this for a few months, and it is consistent. Is there a way to tell if i have a battery issue or is this simply a drop in my cables since this bank is at the end of the daisy chain. Has anyone ever seen this and if so is there a easy to fix it?
Thanks,
Thomas

Hillbilly1878 said:

Is there a way to tell if i have a battery issue or is this simply a drop in my cables since this bank is at the end of the daisy chain. Has anyone ever seen this and if so is there a easy to fix it?

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Swapp positions of the 'low' battery with one of the other batteries and see if the problem stays in the 'last' position orfollows the battery.

12 EG4 batteries daisy chained? You would probably benefit from running each battery to a common bus bar then to the inverter/charger.

If I had 12, I would run 2 independent rack bar systems on 2 T class fuses to a common CCP.. Like Will has in his home system.. no more than 6 that way with the diagonal feed from the rack bus. Then you have to oversize the interconnects a little to get the Imp down.. The video above is good too.. I saw that one. Will goes into this on his mixing battery video.. or if you go to Trophy's home page, Wills video on this is up there.. this is actually critical b/c at the lower charge states you can get a pretty ugly imbalance as the Vm drops off with lithium curves turning from flat to down.. fwiw....

What if you hook you positive and negative at opposite ends of the batteries?

of course diagonal cabling is the best idea no matter what you do no matter the installation, same with long rack buses.. I think its best to Defer to Will.. his videos do a fantastic job of explaining this.

additionally oversizing the interconnect cabling can help. Notice here that Will still has the feed cables going diagonal.. red upper left - black lower attach point. Even though he has a kick butt buss feed with equal lentgh on each batt.. fwiw.. he does about 3 vids on this with the new batts. one of them is when he has them on the floor showing state of charge in a diagonal.

OT Ducati said:

What if you hook you positive and negative at opposite ends of the batteries?

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Thank you all for the suggestions. I am still looking into the issue. I also have noticed that since I added more batteries the low voltage trip does not engage when some of the batteries fall below 10% threshold because others are still above the trip limit. I am not sure how to make them all discharge equally right now. Typically when I see one flashing red I cut it off. I would prefer to have the trip limit work though. When I had 6 batteries all seemed to work as expected. Still work in progress I guess.

Hillbilly1878 said:

Typically when I see one flashing red I cut it off.

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You know that this is based on the bms' estimate of charge, which often isn't very good, and that they start flashing when it thinks it's at 20%? They may be all at the same voltage and state of charge.

On my EG4 batteries they flash red at 10%. I wish the BMS worked better on these batteries. I do not have them connected to each other via the RJ-45 ports. Has anyone else gotten that to work?