Richard and all,
Thanks for the support.
I have a similar situation and is NOT 100% the battery bank fault, but all the same, I have to find a resolution. Existing dual Outback Radian 8048 installed for many years with 22,000AH Gel cell carbon nano batteries. Ran out of cycles for having to charge with a generator in the middle of the night for 3 months out of the year. 4 ton Air Conditioning load (107 LRA Lock Rotor Amps) = 25,680W Means 535 Amps draw (at 48V), 10 seconds 20 times a day. Powered by 15KW solar, 3 each Flex Max 100-300 Charge controllers.
Rack of 6 EG4 Lifepower4 installed about 20 days ago. 4/0 attached to a large busbar system (MIDNITE, MNBCB 1000/100, BATTERY COMBINER) with breakers before the inverter-charge controller. Cross connected negative upper right side, positive lower left side.
Everything appears fine, until the AC compressor kicks in. then the top or second from the top battery blinks and turns off and then cascades down the rack. 6,5,4,3,2,1 and shutdown. Then becomes a bear to get the whole Outback system back up and running.
Look inside the battery bms and short circuit or something like that. Blew out one of the EG4's (shows 53V in the BMS but measures only 42V at the terminals) (have spares at the office and added 1 more battery to the bus bar system. Back ordered 3 and 6 open racks showed up Friday so will rack more batteries but this is somewhat overkill (no pun intended). AC starts sometimes if the solar is charging or if the gen is on. Rest of the time, shut down. Annoying.
I am assuming the Outback Radians see the load and have an instantaneous draw for a second or 2 of up to their overload capacity (16KW each) even though it is only drawing 25KW. The rest of the time this system runs at 3-4Kw peaks, sometimes 7KW if the ac does start.
I think if just bypassed ONE of the Lifepower4's BMS the system would be happy and AC would start, like SolCalKevin's scenario but not a solution, just a troubleshooting tool but not opening a battery without your permission.
Ideas? I see changing to a less beefy BMS (Overkill) would probably solve the issue, (have to find a 48V BMS) Changing the shutdown parameters seems easier.
Shipping from your Texas location is a 10 day problem, and I need to resolve this. (central California)
SOK can get me product but they are slammed like Signature, and MAY have the same issue.
Not at all unhappy with EG4's, for most locations have mini-splits and TOU arbitrage has no need for spikes like the Outback can handle.
Also, I have had to build special cables to monitor ALL the previous EG4 batteries, Do I use the cascade cables RS485 that came with them, and just build the special cable for top battery? I can figure it out, just all the spares out in the field right now, and field cable making is annoying.
Thanks,
Jack Ramsey