battery bank inverters lxi

[davidbrady]

Kevin,

Who's Li-Ion batteries are you using? What does passive balancing mean? Do you run a shunt at each cell to bypass excess charging current and to clamp the cell at a specific charging voltage. That's a good setup for a lot of applications, but in an RV I'm thinking that using the batteries as in the middle 80% of their capacity (in all practical sense) might provide us with the best performance/longevity tradeoff. What are your thoughts?

I probably shouldn't have said "deeply discharged". In fact, anytime my coach is disconnected from an AC source upon reconnection the inverters both go into bulk charging. The issue of sending power back into the grid is disabled on my inverters. What happens is when the chargers are near the bulk setpoint voltage (28.8) one will likely continue on into absorption while the other transitions to Float. This isn't really an issue because one charger is more than capable of supplying the necessary absorption current, so no time lost in overall charging. The inverter that transitioned to float will actually try to lower the battery voltage to the float setting (26.6V) by inverting. The AC power it produces is used by AC loads in the coach up to the maximum 33A rating of the inverter. Only when the 33A draw is exceeded does the inverter augment with shore power. This all takes place while the other inverter finishes up the absorption phase. So, in essence the inverters are "fighting" each other during absorption. Welcome to the world of hybrid inverters! LOL

I believe the above can be cured by using the Xantrex Parallel Stacking cable, but then we have a 240VAC house system and I'm told that the stacking cable has its own set of issues like shutting off both inverters for problems only seen by one inverter, so few converters use this approach.