Phantom Chassis Battery Drain

[Michaels]

Found chassis batteries (two 12v) to be dead. Replaced with new. Takes only three days parked and new batteries are dead again. Recharged w/same result after three days. Recharged again and turned off Chassis Battery Disconnect Switch. All is well but lose power bay door locks, all slides, etc. Have been plugged in to shore power at all times, however shore power only charges house batteries, not chassis batteries. Disconnected fuse to slides with disconnect switch on but battery drain continued. What is best way to troubleshoot this phantom drain?

[GaryKD]

Hi Michaels,
You'll need to work with a volt meter, a couple pieces of wire (about 2 feet long for comfort) and two pairs of alligator clips. At the 12 VDC chassis fuse buss one fuse at a time, you'll need to pull a fuse. Connect the meter in between the fuse and the circuit. Put the meter on AMPS. When you find a circuit that has a draw (assuming everything is turned off), you have the guilty circuit(s). There may be more than one. Once the guilty circuit(s) are found, one must determine the guilty appliance on that circuit.

Also, consider putting the chassis batteries on a charger so that when connected to shore power the chassis batteries are charged. There are several chargers on the market that are small and can easily be connected. A sample is at Motorhome Supplies and Camper Parts : RV Surge Protector : RV Accessories : Blue Ox Baseplates : RV Store : Motorhome Covers - RVUpgradeStore.com

[Paul R. Haller]

Turn everything off. Take out all 12 volt fuses. Then, take an amp reading across each fuse. Write down result.( or if you are lazy disconnect a single battery lead and check that for current. Be carefull,,, Most VOM have only a 10 amp max meter.) Add all draws to get total amp draw. You now have your total draw and how much on each circuit. Go after the highest draws first. Is everything turned off? Trace out the circuit and see where the load is on the circuit. Often it's things like radio, LP detector, clock, LED lights in switches, refer circuit board, etc. Find out what you do not need and add switches to turn off phantom draws or add a whole house relay switch.
-Paul R. Haller-

[bdpreece]

If your coach is designed not to charge the batteries from shore power then you need one of these Camping/RV Battery Chargers | Battery Chargers by BatteryMINDers.com

In my case my coach is supposed to charge the chassis batteries from shore power but is not doing so at this time. You can see my thread at Dead Starting Batteries

[Michaels]

Thanks Guys. After a bit more research, discovered that my rig has a Xantrex Digital Echo-Charge which is designed to trickle charge the chassis batteries from the house batteries. It has two fuses and after checking them, found one to be blown. Replaced the fuse, green light comes on on the charger and getting 13.1 volts out of the batteries with the disconnect switch on. Will give it overnight and check voltage in the morning. Not sure what blew the fuse. Perhaps when I changed out the batteries I caused a short. If not, fuse will likely blow again, then will have to troubleshoot why. Appreciate the help.