[RE-wrenches] Strange battery overvoltage issue (Midnite AIO / Lithionics Battery)

[Jay]

I don’t understand how 3 inverters on a single buss could be recording such wildly different dc voltage readings. Regardless if the inverters are independent or paralleled. 

I don’t have those battereis specs but would expect absorb if there is any to be less than 90 minutes? 
Or did the issue occur at the exact end of absorb?

What a pain. 

Jay



> On Jan 24, 2026, at 1:36 PM, Jason Szumlanski via RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> 
> 
> I have a triple stack of off-grid Midnite AIO connected to a 60 kWh lithionics battery bank (51.2V LFP) in open loop. Today the site had BMS shutdowns (there are two BMSs, one for each 30 kWh stack of batteries). Both BMSs shut down about 90 minutes after the solar got the batteries to 100% and were just meeting loads with solar.
> 
> I got some data from Solar Assistant (attached) that shows erratic voltage readings from each of the three inverters. This has never happened at this site before. Some of the voltage readings exceeded 60V, which I am guessing caused one or both BMS to shut off and come back on, possibly quickly. 
> 
> I do see some solar charging spikes, so it looks like the inverters would detect a low battery state and start charging, raising the voltage of the batteries quickly, and the process repeating itself.
> 
> Any ideas on what the source of the problem might be?
> 
> Thanks,
> 
> Jason Szumlanski 
> Florida Solar Design Group
> 
> 
> 
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