[Richard]

There are a lot of different ways of keeping the coach plugged in, and keeping both the chassis and house batteries charged. 

Newell equipped many of the coaches with an echo charger or trickle charger that takes power from the house batteries and maintains the coach batteries. 

Some leave the batteries merged so that the inverter/charger keeps the chassis batteries up. 

Sounds good, but in my case I noticed that my chassis batteries would stay charged while in storage but not really up to full charge. It took a while to sort it out, but this is what I think. I float the lithiums during the winter at 13.4. That’s lower than what I keep them while using the coach, but this is one of my strategies for battery longevity. The problem is the echo charger only charges the chassis batteries around 0.2 volts lower than the house batteries. So my chassis batteries would see 13 to 13. 2 over the winter. 

Since I am plugged in, and cheap, I chose to go the financially efficient way. I installed this maintainer on the chassis batteries. https://www.amazon.com/NOCO-GENIUS10-Ful...mREALw_wcB

It’s a NOCO Genius 10 amp maintainer. I hardwired to the parallel starting batteries and mounted the unit on the forward firewall. It is not intended to rescue a dead battery but keep the ones I have fully charged. I have been using this setup all winter. I am happy to report that the engines spins up quickly whereas when the chassis batteries were on the trickle charger, it would be a lazy start.

[BusNit]

I have that charger and a rescue version from that company. You have one of the finest battery maintainers made. I keep a small plug in version for the motorcycle so it is always ready to go. In fact, I have four of the smaller plug in ones for our cars if we leave them unattended.

[Latitude 28]

I had bought one back when we had a Smart car with an AGM battery. I now keep it with the coach in case we run down the CRV battery during the tow as well as 12vdc power supply. Very good product.

[Jonestead]

I haven't been testing batteries like I should so this is very helpful information. Thanks again for sharing (and adding to my todos)

[Richard]

As others stated, we too have NOCO charger/maintainers hooked to fleet that stays here in Florida while we travel. My only long term data is the battery in the beemer lasted 13 yrs staying on the NOCO while parked.

[Jack Houpe]

I'm a fan of Victron, not only do they offer user defined but have presets for AGM, Lead acid or Lithium. My configuration is different from others as I have 48vdc bank for my Growatt inverter and then I use two Victron MPPT solar chargers to charge the two 8d house batteries and the two 8d engine batteries from the 48v batteries. This unit will do Lithium and  you could have it float at what ever voltage you want that way your echo charger can keep the engine batteries at a higher voltage.

https://bluemarine.com/products/victron-...pgEALw_wcB