Re: Jackery 400

"Bob La Londe"  wrote in message news:vekfri$1dhm6$1@dont-email.me...
Same here except 36 volt for the boat.  I wish they had a 12V with
cranking amps high enough for a starter motor.  I've also been thinking
about getting a couple high cap 12s for the travel trailer.  Highest
peak loads would be the brakes in an emergency I reckon.  That
continuous capacity would be nice to have.
Bob La Londe
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LiFePO4 amd AGM both charge at 14.4V and float around 13.3~13.6V, so they can be paralleled while charging or discharging to have the high starting current capacity of AGMs of perhaps less Ah capacity and cost. Their discharge curves are somewhat different, LiFePO4 stays above 13V while AGM quickly drops to 12.6V, so I'd disconnect them during storage so the Li doesn't slowly run down trickle charging the AGM.
https://communityarchive.victronenergy.com/questions/119423/mix-agm-and-lifep04.html
A clamp-on ammeter that measures DC would be very useful to understand how the two batteries perform when paralleled, especially when on a low current maintenance charger.
The simple way to accommodate their different long-term storage characteristics would be separate maintenance chargers. The LiFePO4 charges to 14.2~14.4V and then stops accepting current, the AGM continuously draws a small current at its ~13.6V float voltage. I don't know the consequences of floating the Li partially charged at the AGM float voltage, which will depend on the output of the float charger. I build my own with volt and amp meters and don't have experience with commercial ones.
Before connecting them in parallel you should charge both to ~13.6V to avoid a large current between them.