Hi all.

I run a 3k Multiplus here on the farm. Lately it's started giving low battery errors, switching off the AC for a second and then recovering.

This has happened at night(battery only) and while the sun's shining and doesn't seem load dependent.

Is there a failure mode that might cause this? 

I've checked my DIY 12kW Lifepo4 bank and cabling and that's fine.

One wierd thing is the inverter refuses to start my compressor - it goes straight to low battery error. So not liking inductive loads all of a sudden.

Any advice appreciated. Might be time to upgrade.

Ian

Edited May 30, 20224 yr by Ian

5 hours ago, Ian said:

One wierd thing is the inverter refuses to start my compressor - it goes straight to low battery error. So not liking inductive loads all of a sudden.

For your information: Any induction motor draws at startup up to 5 times rated current. With the compressor against pressure that may last enough to pull down the battery.

Coordinate the "low battery" setting with the data given by the battery manufacturer. Example: The datasheet of my LFP battery says that the BMS will cut off at 40.5V. I set the inverter "low battery cutoff" at 42V.

Sorry, perhaps I wasn't clear. This system and battery have been operating together faultlessly for the past 2 years. That includes running the compressor. I just thought that the 2 scenarios together might narrow down finding a fault

17 hours ago, Ian said:

Sorry, perhaps I wasn't clear. This system and battery have been operating together faultlessly for the past 2 years. That includes running the compressor. I just thought that the 2 scenarios together might narrow down finding a fault

Perhaps your batteries, if lead/acid, come to their end of life.

Hi Ian,

 

Where did you get your lifepo cells?

Hi Ian

I had the same problem, Also 3KVA Victron with a similar error, mine was a faulty BMS in the Lifepo4 battery. I spoke to an installer and according to him he has only seen the bms fail on lithium batteries...

 

 

regards