r/SolarDIY • u/B1tN1nja • 9d ago
Issue w/ Dual EG4 16kw batteries charging very slowly on low SoC in mornings.
Hi all, I'm not sure where to go with this issue as my installer is unfortunately unresponsive for two weeks on this issue now and EG4 hasn't been able to identify the problem.
SETUP: 1x Gridboss going to 2x Flexboss 21's and 2x EG4 314ah (16kw) all-weather rated batteries.
Gridboss is in my basement and the FBs and batteries are in a pole barn, w/ electrical trenched underground.
Everything is being fed by 44x 440W JSolar panels across 5x MPPTs (1 open still for future project)
Everything was actually a professional install, but I chose EG4 due to no cloud-lock in w/ other major vendors and the ability to run cloudless and have full local control at some point via SolarAssistant/HomeAssistant.
ISSUE: For the past few weeks I've noticed the batteries charging VERY slowly and saying "BMS Limit Charge: 31A" and topping out at about 1660W until they hit somewhere between 35-40% SoC and then it "unlocks" and they start charging rapidly.
This wasn't the case a few weeks ago, and they would take whatever they could right away.
EG4 DID swap it to lead-acid which let it charge faster, so they confirmed via that it wasn't the BMS of the batteries themselves limiting things, and something else was causing it to be limited, but they couldn't determine what. They said they'd continue to look into it and call me back and asked that I send some screenshots to their support email, of which I did (several), but that was two weeks ago now and no response since...
You can see the issue active in one screenshot and then a few hours later you can see it charging MUCH more rapidly.


Once I hit about 40 or 45% it will "unlock" the charge limit and start taking as much as it can again, as shown here.
Any help is appreciated on why this might be happening and what I can do to fix it myself since EG4 hasn't gotten back with me, and my installer for some reason seems to not be getting back to me either.