Lithium/FLA hybrid battery system
The lithium/lead acid hybrid battery threads are still surprisingly accumulating views tho I don't know of anyone else that has put one in.
As an update it works very well in a 100AH lithium/80AH FLA system in a class B and a 200AH lithium/225AH FLA in a class C.
Both of them require user intervention and use/charge procedures are constantly modified. One given is that both battery banks are at 100% by 5PM every evening.
For the class C, with less than 40AH daily use, the FLA is left at 100% charge and power drawn from the lithium. Charging the next day is done by solar and topped up by a short generator run (10 minutes) if necessary.
Larger daily power draws are handled by running the evening on FLA, nighttime heating by mattress pad on inverter and lithium. Morning heating is handled by catalytic heater or furnace. A morning generator run of 30 minutes or so brings the lithium to 100%. FLA will then be around 80%. DC to DC charger then used to charge the FLA and solar directed to the lithium. This can be unattended during the day with a short generator run to top up the lithium at 5PM.
The class C is usually not driven but if it is we have several options. The battery switch can be put on both and charge by alternator and solar. When stopped for the day if the FLA is not charged turn on the DC to DC charger or run the generator as necessary to get both banks to 100%.
The class B is usually driven daily. A DC to DC charger is set to 40amps to charge the lithium from the FLA which is charged by the alternator. Generator generally not needed as lithium is brought to 100% very quickly. DC to DC charger turned off at the first rest or fuel stop but not necessary as it is a smart charger set to lithium.
Max charging rates into the 200AH lithium seem to have dropped five amps or so to 90 amps as the lithiums age. Other than that, no problems, no blown circuit breakers and no fire!