Generator - House Batteries

[Robert Lariviere]

We are new to the coach world - we've had our coach 1 year.

We are not able to travel without running the generator. The batteries are fully charged when we leave for a trip. WE had them all tested and were told they are all good, they are 2015 batteries.

Some people have told us we should be able to run without running the The inverter is set to run the generator for 1 hour when it comes on. When stopped for the night running on battery/generator power it goes about 4 hours before the generator comes back on. WE are only running the refrigerator during these times. Even trying not to have anything else plugged in, except the microwave.

The manual tells us the engine batteries should charge the house batteries while going down the road, that does not seem to be happening.

Bob Lariviere
2009 Beaver Marquis
45 feet
625 hp Caterpillar engine

[David T. Richelderfer]

It could be that your engine's alternator has failed.  If so, then the chassis batteries are not getting charged.  And if the chassis batteries are not getting charged from the alternator, then neither are your coach batteries.

A common source of alternator failure is overheating due to too much charging demand.  If your two chassis batteries are discharged AND your several house batteries are discharged, then your engine's alternator will overheat because it is working too hard to charge too many batteries for too long a time.

The key is to reduce the demand on the alternator by running the generator for 30 to 60 minutes (or using shore power) to charge up both battery banks before starting the engine.  Of course, this assumes your inverter/charger is working properly such that your generator (or shore power) is charging both battery banks.

Our coach is a power hog.  We cannot go all night without the Auto Gen Start in the inverter starting the generator due to too low a voltage in the house battery bank.  When dry-camping we have adapted; we have a portable 30 amp gasoline generator in the pickup that we run most of the time, including overnight.

[Joel Ashley]

I'll echo David's comments in that many new to coaches break dry camp without using the genset to punch up the depleted house batteries.  Then the poor alternator overheats trying to do that extra work on the road, and eventually fails. 

It's also possible your BIRD (Bidirectional Isolator Relay Delay) has a bad connector or something.  On the highway the BIRD allows alternator charging to switch (via the Big Boy solenoid) over to the house bats once the chassis ones are up, and on park power the BIRD switches inverter (or genset charging) over (again via the Big Boy) to chassis bats once the house set are up to snuff.  A simple voltmeter test on the house set with and without the engine running might be telltale to a knowledgeable tech. who works from that back.

Is your inverter panel set to off, as you may think everything but the fridge is off but maybe not?  The fridge doesn't run off the inverter and should be on propane dry-camped or on the road except when the genset runs.  The inverter panel should show your voltage while camped so you can monitor it.  The Aladdin should reflect discharge rate in amps as well.

Joel