Electrical 12Volt

Check your mirror heat. I had a problem with the engine battery dying repeatedly and it turned out to be the mirror heat was on. Apparently in my coach, the switch is always hot.

Moved from technology corner

First the boost switch is not the boost switch, it is the remote control for the boost switch.. (Well, it would be more correct to say the boost switch IS the remote control for the boost SOLENOID or RELAY)

And while switch failures are rare, they do happen.. Solenoid failures are more common, as are alternator failures.

Next page: How old is your Motor home? Today, many (not all) motor homes come with what is usually called a BIRD here, Bidirectional Isolator Relay Device/delay.

This system works as follows.
Going down the road. The alternator charges the chassis battery once a threshold voltage is reached (Usually about 1 second) a timer starts and a short time (Like 30 seconds) later the isolator closes and parallels both house and chassis so they all charge... When the voltage drops, it opens the isolator so you do not suffer both battery banks dying.

And

When parked and plugged into shore power or running generator:
The house converter (or charger section of an inverter/charger) charges the house batteries.. When the threshold voltage is reached.. It closes the isolator so the chassis is also charged. If voltage drops.. Same as above.

With this type of system if you park for say six months. (Plugged in) all batteries are charged.


Older motor homes (And some still today) have a one-way system.. in this system when the engine starts, the isolator closes and the alternator charges everything.

But when parked ONLY THE HOUSE batteries are charged.

If your Rig has this system... You can get a Trick-L-Start unit, simple 3 wire hookup (house side of isolator, chassis side, and ground) and the T-l-S provides the reverse charge path.