Starting battery problems

Possum · 10-22-2012, 11:20 PM

My starting battery goes dead after about 1 week unless I keep a charger on it. We've measured a constant 1.12 amp draw on the battery even with the key off. Does anyone have any idea what causes such a draw in a 1994 30 Adverturer? Driving me nuts as I can't find the cure. Are the propane and CO detectors run from the starting battery? TIA

augoldminer · 10-23-2012, 01:27 AM

Turn off everything in the motor home. someone may have hooked up something new in the circuit for the starting battery instead of the inside system. then check for a voltage draw

Pull the fuses on the vehicle fuse panel(not the service fuse panel) and check across each fuse holder for voltage.

If you find nothing another thing to try is check by disconnecting all the small wires from the hot side of the starter relay and meter the wires one at a time till you find one with a load on it. some one may have added a accessory on the starting instead of the service battery system

Put a volt meter on the hot post and the other meter wire on the small wires one at a time and if one reads 12 volts the circuit is drawing a load.

My used RV had a number of these connections to the wrong service.

Once you have the problem cleared put a battery isolator between your service battery system and your starting battery system so that your starting battery is charged as needed by your service battery system charger.
Lynx/95 Amp battery isolator (08770) | Battery Isolator | AutoZone.com

I have a solar panel that keeps my service batteries charged and through the battery isolator it also keeps the starter battery charged when the RV in not in use. and not connected to shore power.

kb7uxe · 10-23-2012, 12:19 PM

could also be a failed diode in the alternator...
a light in the engine compartment.. or something similar..

kb7uxe · 10-23-2012, 02:47 PM

problem with batteries, is the stronger one will always try to charge the weaker one when connected in parallel. So if you have 2 batteries connected in parallel, could be one is getting weak and inherently draining the other.. try installing one dis-connector clamp on each battery, so when in storage, each battery is isolated from the others. Batteries in storage tend to last much longer that way.
this sounds more plausible as a place to start checking....

Go Dawgs · 10-24-2012, 08:13 AM

I had the same issue with mine and even had to resort to a new battery and couldn't figure out the problem. It would draw it dead in 7 days. Went and recheck all connections and found that the previous owner when he installed a new indash radio he made some changes to the setup. He had the radio and digital clock on constant draw ( I also completely took the CB out since I don't use one). I went through all the acc. and reconnected the wires for both the clock and radio. Now they work like the SUV and the draw in a week was less than 0.15 after a full charge.

I have the clips situated so if I want to have the dash radio or clock while parked I can move the clips in about 30 seconds.

Good Luck
Arnold

Possum · 10-24-2012, 10:13 AM

I will look at that possibility as the last owner put in a real fancy radio / cd combination job that has great sound. That may be the problem.

dirko · 10-24-2012, 12:52 PM

Hi Ho: It's almost impossible to guess where the load is connected, so the best thing is just too do as someone else suggested is to remove the fuses one at a time until the load goes away. I assume you have an ammeter since you measured 1.5 amps. If you had a 150 amp. hr. battery it would be drained in 100 hours or about 4 days, so it looks like you are one the right track. I assume you have the meter hooked to one of the battery leads.

Just get a helper to watch the meter and start pulling fuses.

garykk · 10-24-2012, 01:23 PM

Quote:

Originally Posted by Possum

I will look at that possibility as the last owner put in a real fancy radio / cd combination job that has great sound. That may be the problem.

That's probably your problem, the radio (on most anyways) has a yellow wire that constantly draws power for the memory etc. On our MH when I disconnect both house batteries and starter battery, I will lose all memory in the radio.
Small price to pay for battery life