LFP on Shore Power with Inverter/charger?

The best part of this was last spring when a storm blew through and power was out for a couple of days, we didn't even know it till a couple hours later when I went outside to check out the damage and the campground owner came by to apologize for the power lost and not knowing when it would return. It made no difference for us because we always fill the water tank and it a seamless unnoticed event when going from 120v to 12v inverting power and solar to help with the heavy lifting. ;)

So the inverter /charger stays 12v powered so it can run the pass through by getting that 12v from the batteries which are being cycled. If you need more 120v than the pass-through has, you get inverter help with the hybrid. Pretty neat!

I was thinking you could clamp a small float charger on the inverter/charger's DC terminals to keep it powered up and just isolate the LFPs, not floating them. If you did that with solar it wouldn't work at night.

If you had a separate inverter and a converter, instead of an inverter/charger, you would not have this. The converter would supply the 12v with LFPs isolated, not floating.

I don't know if there is much penalty in cycles or whatever if you did float the LFPs, but it would be good to have the choice I guess.

EDIT--if the inverter/charger has a "no float" option and the charger turns off, how does the inverter stay powered up? You want the battery to not float but that would put a drain on it ?

I read some inverters have 2 stage charging. Bulk, absorption and off. At the set point, 12 to 13 volts, the charger repeats the 2 stage.

This is what I do.... right, wrong or indifferent.

I set my inverter (hybrid) to loadshare 30a or 50a depending on the power source. I turn off the charger but leave my solar on to charge if needed so the inverter is passing through power, powering everything 120v but the 12v loads are carried by the batteries. When I was doing this it was colder weather so the furnace and misc 12v loads would use roughly 10-15% DoD (50-75ah) solar would top them off and float at 13.6v. This was last spring for a couple months during covid first started and didn't want to stay in hotels for work. Also did this way 5 years ago before doing the boondocking fulltime.

Lot of cycles of use with heavy draw items everyday. Past 2 weeks with the heat (90-100f) kicking here in AZ I've been spliting run time of the generator, batteries & solar using the air conditioner. When air conditioner, tv, humidifier and other inverting loads there will be 2-3 hours of 100-175ah inverting, stopping at 60% SOC then do the gen for air conditioner for awhile longer but not using the gen to charge the batteries. By the time morning coffeemaker, microwave use is finished SOC is 40-45% and solar will charge back up by 2pm roughly when I switch the air conditioner back to batteries/ solsr and do it over again.

Today started moving north so shouldn't have to do this for a while again. :)