ANT BMS - Load Testing Week #2

[TedH]

I just completed week # 2 of stress/load testing of my 5Kw CALB Lifepo4 battery bank connected to my AIMS 6000watt Inverter/Charger.

Until Sunday all was well. Sunday morning, I went out to check the status of the system and found the inverter/charger was Alarming (constant tone). The batteries appeared charged using the Ant BMS app. One telltale was that 3-4 of the cells were at 3.5+ where the rest were 3.4+/- volts.

I reset the system and the inverter/charger went into bulk charging. Not a problem initially as it was doing that Saturday and it appeared the cells had been recharged overnight; perhaps it needed to finish.

However, it would not switch to run off battery pack even though the batteries were ready. I turned off the shore power and inverter came online, then it alarmed.

I suspect the 1-2 Ant BMS I am using are not well. At this time, I have shut down all but the lightest load on the system and system is on shore power, bulk charging (but, there is no voltage currently going to the cells). Going to turn it off again until I can do a thorough assessment. But, I suspect the two bms are having issues.

 

[TedH]

In the meantime, I am investigating more reliable BMS and Monitoring solutions from Electrodacus.

 

[TedH]

Reviewed my documentation and confirmed 0 charging on Float setting for Lifepo4. That explains inverter/charger float charge light but 0% charge. I have since turned off shore power and forced inverter to run on batteries. One bank is supporting, the second was not. Checking status in a bit. I suspect that is source for the inverter/charger alarm.

 

[TedH]

It now appears the inverter/charger 'automatic transfer switch' is not working. It may have failed. Not what I expected from one of the most expensive Aims inverter/chargers ($1,600). Add to that, I ruined the first one so I'm in this for $3,200 with likely two failed Aims inverter/chargers.

One thing I observed when the inverter/charger switched from shore to battery was that it made this loud 'thrumb' sound (once, each time it flipped to inverter), the lights blinked and then it was in inverter mode. It was almost as if it was a 'shock' to the inverter to flip the switch. I've observed some YouTube videos of those cheap $150 shore to inverter switches and they do not appear to make any loud noises. Perhaps that is because they are lower capacity (2500 watt). However, I was not running more than 1500watts of power thru it at the time it switched.