[RE-wrenches] Alternate LVD shutdown

Bill Battagin frenergy at psln.com
Thu Jan 2 08:21:32 PST 2025


I am trying to use the "low battery disconnect" in aux mode in a newly 
installed OB FM80 CC for Li battery low voltage protection. I can't use 
the 19 year old OB VFX inverters for obvious reasons. The plan is to run 
the 12 volt output from the aux output to a NC relay to open it at 50 
VDC of the bank of SimpliPhi 3.8M batteries.  50 VDC is SimpliPhi's 
recommendation for LVD. The "output" of the relay would be connected to 
the VFX's  ON-OFF landings of that little green terminal block in the AC 
side of the inverter and just act as a simple switch for the inverter to 
turn it off to save the batteries.

             I'm using one of my newer FM80's as a test run and have 
programmed the voltages in  Low Battery Disconnect mode and then put it 
in auto mode.  However, as the CC goes below the voltage set point, the 
AUX output does not turn on (time set for 5 seconds), as evidence in the 
CC's home screen and by checking for 12V at the AUX terminal block.

             Any ideas of what I'm missing here to make this work? I 
know the other solution, thousands of $$ for new inverters which would 
be great but these folks have already invested quite a chuck on array 
replacement and charge controllers.

Thanks for any experience with this.

Bill

Feather River Solar Electric
Bill Battagin, owner
4291 Nelson St. (Shipping)
5575 Genesee Rd. (USPS, UPS)
Taylorsville, CA  95983
530-284-7849, 258-1641(cell)
CA. C10 Lic # 874049
Solar Powered since 1982
Home of the Sunny Side Up


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