Electrical 12Volt

[trop-a-cal]

After replacing the engine battery due to the old one dying for an unknown reason, the new one did the same thing. I have a battery boost switch that is spring loaded so it goes off when you stop pressing it. It uses house batteries for the boost if engine battery is not turning engine over. I believe the pressure switch may be not going off due to age,(18years). Has anyone had that problem with a bad boost switch? If that is not the problem then juice is being drawn elsewhere, which I can't locate so far. The unit is a 1997 Tropical Chevy P32. Thanks for your help. Only other odd thing 12 volt related is the starter switch for the generator, when engine is running causes the speedometer to jump when holding that pressure switch down. It's like a back feeding, maybe diodes are needed to isolate current, or dash has the short causing both?

[jplante4]

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.

[MrWizard]

Moved from technology corner

[wa8yxm]

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.