House Battery Drain UPDATE

[gmcgene]

1998 36fdss Alpine

Need help and direction to find what is draining my house battery. If unplugged from shore power it will go from fully charged to below 9 volts in a couple of days.

Yesterday I removed all the fuses from the service panel in the hall. Turned the main house batt switch OFF.

With fuses removed and main switch off I still get a sizable spark when disconnecting the negative battery cable.

Where do I search next?
I understand that the smoke and CO detectors are not fused but I don't think they should draw the battery down in short time.

Thanks for your advice.

[select55]

Originally Posted by gmcgene

1998 36fdss Alpine

Need help and direction to find what is draining my house battery. If unplugged from shore power it will go from fully charged to below 9 volts in a couple of days.

Yesterday I removed all the fuses from the service panel in the hall. Turned the main house batt switch OFF.

With fuses removed and main switch off I still get a sizable spark when disconnecting the negative battery cable.

Where do I search next?
I understand that the smoke and CO detectors are not fused but I don't think they should draw the battery down in short time.

Thanks for your advice.

kinda weird you only have one house battery? perhaps the charge solenoid from the alternater is stuck on ? go feel it and see if its hot when battery hooked up

[rkf]

Just install a battery disconnect switch. Or add solar.

[Dave Fernandez]

I believe the 1998 Alpine had 2 8D batteries, one for the Chassis and one for the Coach. The inverter is connected to the battery and that can cause the spark when you remove the ground cable.

Have you had a load test performed on the coach battery? It could be going bad. You should also have someone test the amp draw with the inverter connected and disconnected. The 8D is not a deep cycle battery. If you have to replace the 8D battery you should have 4 6 volt batteries installed.

[powercat_ras]

It is pretty typical that coaches use about 20 amp-hours per day to power the refrigerator control board and the Propane Gas detector, unless their coach battery disconnect switch ( often called the salesman switch ) is put into the off or storage position. If you don't already have this switch then you could add one.

If you have been letting your battery drop to 9 volts each time this was done you have reduced the batteries storage capacity. Any time you let its resting voltage drop below 11.5 volts you are permanently reducing its storage capacity.

[Old Scout]

Its probably the inverter--inverter is connected directly to the bats--no switch [even in the 98, I think]. Only way to totally isolate the bats is to disconnect the negative posts......
PS--Don't know if your 8Ds are rated for deep cycle or not but it is likely you have pretty much killed them if they have repeatedly gone to 9 volts--especially true if they are a few years old....
PSS--don't install another bat switch unless you go big--like 300 amps.

[EngineerMike]

For the house side, this 350A Blue Sea switch would work.

For the starter battery side, you need to pass about 750A to start a cold ISL or ISC size diesel. IIWMI wouldn't put a switch on that, I'd just bite the bullet & pull the negative cable. You might be able to make it work by splitting the hot or ground side using a Y, i.e. running --<== switch ==>-- to a Cole Hersee 880175 switch, rated for 500A (I'm assuming that's 500/leg and not 2ea @ 250A).

[select55]

Originally Posted by gmcgene

1998 36fdss Alpine

Need help and direction to find what is draining my house battery. If unplugged from shore power it will go from fully charged to below 9 volts in a couple of days.

Yesterday I removed all the fuses from the service panel in the hall. Turned the main house batt switch OFF.

With fuses removed and main switch off I still get a sizable spark when disconnecting the negative battery cable.

Where do I search next?
I understand that the smoke and CO detectors are not fused but I don't think they should draw the battery down in short time.

Thanks for your advice.

as others have said if you have a inverter and I assumed with one battery you did not it will cause a spark when u first connect it
and draws power although certainly not in 2 days
charge the battery right to full like 13+ volts and then let it sit unconnected for 3-4 day and see how the voltage is
if its down to 12 or 12.2 the battery is no good
although someone suggest four 6 volts and I agree a single 8D is no where near
four 6volters in amp hour ratings two would be about the same

[Unplanned Tourist]

If you really want to disconnect the batteries completely, go to a truck shop Peterbilt, Kenworth, Frieghtliner, etc. and get a couple "Night Switches" or maybe they will call them "Battery Disconnect" switches. We used them in the Peterbilts and they cut the power completely on the positive side. They will take 1500 amps no problem, so don't worry about not starting. Some of those old trucks took a lot of cranking before they would start in cold weather! Especially the KT Cummins and 3408 Cats.

[gmcgene]

Thanks to all who gave advice and suggestions.

Posting the follow-up in the hope of helping other "Electrically Challenged' RV'ers.

As it turned out - the fridge was turned ON and even though it automatically switched to propane there was a .58 amp draw to power the indicator lights and whatever else is running.

With the fridge off the draw reduced to .02 amps. Insignificant- I think.

After 4 days and change the house battery voltage has reduced from 12.8 to 12.65.

I don't know what is drawing the .02 amps but I don't think it will be a problem with an 8D battery with reserve capacity of 430 amps.

If I'm not using the coach for a while I'll hook up shore power or disconnect the house batt.

[vsheetz]

If on shore power in storage why disconnect the battery? Onboard charger should maintain the batteries.

[wa8yxm]

From 12.8 to 12.65.....

12.6 is normal resting voltage for a FULLY CHARGED battery

Are you sure your meter is calibrated?

[Davidjeff]

Many times the propane leak detector is always powered, I have mounted a switch enabling me to cut power to that item and then added to my pre-flight check list to toggle it to on before camper use of any kind...

[gmcgene]

Vince,
You are correct.
This inquiry began because on a recent trip my less than one year old 8D house battery discharged faster than it should have.

After returning home and charging the battery with my garage charger and leaving it disconnected from shore power for 2 weeks the battery was discharged below 10V again.

I needed/wanted to determine if the battery was defective or if there was some extra-ordinary draw discharging the battery.