RV battery maintenance

Batteries die quietly in storage. The 2019 Fleetwood Class A gas manual is blunt about it: a discharged battery will freeze and be damaged.

Two banks, two jobs

The manual treats the house batteries as the reason the lights and most appliances work. The chassis batteries run the engine side.

The banks charge each other in specific cases. The alternator charges the house bank while you drive, and shore power or the generator charges the chassis bank.

The battery cutoff on the monitor panel (the manual also calls it Aux) disconnects house 12-volt loads. Turn interior lights off before you flip it.

In storage

With no shore power, turn both the house and chassis disconnects off. With shore power, leave them on. Either way, check voltage while the coach sits.

The storage chapter doesn’t give a target voltage in the passages this guide draws on, so we haven’t added one. Your battery maker’s sheet is the place to find it.

Flooded, AGM, or lithium

Section 9 of the manual has more on battery maintenance and load testing, and it points you to the OEM manuals in your owner’s information file. Follow those for watering (flooded lead-acid only), terminal torque, and replacement.

Lithium batteries are sealed. Don’t maintain them like flooded cells, and don’t assume the stock converter’s voltages match a lithium charge profile.

Size it, then care for it

The smallest bank the Megawatt calculator recommends is its 12-volt 100Ah listing. Use the calculator for size and the battery maker for care.

If the coach goes dark, the problem fixer walks through the cutoff and the fuse panel before it suggests buying anything.