Something is draining my battery very quickly

freestyledude · April 23, 2013, 11:03 PM

Something is killing my battery in a hurry.... hmmm.

vincewarde · April 23, 2013, 11:03 PM

You have a short between positive and ground somewhere. That the easy part, because nothing else would fry the fusible link and cause a constant drain on the battery. In theory, if the short to ground is on a circuit protected by a fuse, that should blow first. If you have a wiring diagram, you should be able to see what is not on a fused circuit.

An AMP METER, connect at the battery, should tell you how many amps the short is drawing. You could then connect and disconnect items until you find the circuit that has the drain. Then you can run it down from there.

On my coach, the batteries are disconnected when in storage. The only thing that remains connected are the solar chargers. In vehicles as old as ours, that may have been worked on be Lord knows who, the chances of a "sneak circuit" draining your batteries is very real. It only takes an amp or two to dram a battery.

DaveVA78Chieftain · April 23, 2013, 11:04 PM

You wil have to disconnect circuits to trace the drain down. If you need it, I added the 76-77 chassis wiring diagram to the Free Manuas section in the members area. It was the only link missing from our ist of diagrams. Make sure the AUX Start reay is de-energized. It cross connects the house and chassis systems.

Dave

freestyledude · April 25, 2013, 02:43 AM

I saw that the battery switch on the dash was set to 'dual' and switched it to single battery. No more drain, which leads me to believe that the drain is in the cabin somewhere, correct?

Elandan2 · April 25, 2013, 10:27 AM

I could also be the coach battery itself. If it is no good, it would drain your chassis battery quick in the "dual" position. Rick

Froggy1936 · April 25, 2013, 10:58 AM

Here,s another little trick that you probably already have one of Useing a 12V test light disconnect the positive lead from the batt and install the test light between the positive cable and the positive post of the battery if you have a draw the light will light Sometimes you can tell by the brightness of the test light type of draw Once you have disconnected the offending item the light will go out In very rare cases 2 or more items at the same time can throw ya leave all items dissconected till problem is found Fastest disconnect is pulling fuses Then reinstall till light returns VIOLA short is discovered

Frank

DaveVA78Chieftain · April 25, 2013, 05:04 PM

If the MOM switch in dual is draining the chassis battery when the ignition key is OFF, then the MOM switch has been modified. When set to DUAL, the MOM switch should only energize the Aux Start solenoid when the ignition key is in the RUN position. That is to prevent inadvertent discharge of the chassis battery when camping.

Dave

moonlitcoyote · April 25, 2013, 05:57 PM

Ah Dave, you ruined my hope that that is why my chassis battery gets drained whenever parked. I thought maybe I left it in the dual position. Oh well, just another thing to work on when we get home.

DaveVA78Chieftain · April 25, 2013, 07:07 PM

MJ,
Does not mean the relay could not be stuck (contacts welded together) in the energized position. One simple check for you to make is take a voltmeter and see if there is 12VDC on the little post of the solenoid to ground (3 post solenoid). For a 4 post style solenoid measure across the 2 small posts. If there is 12VDC there with the ignition switch OFF then something is wrong at the MOM switch end.

Dave

moonlitcoyote · April 25, 2013, 07:39 PM

That sounds easy enought, except one thing.. What solenoid are you talking about?

DaveVA78Chieftain · April 25, 2013, 07:55 PM

MJ,
Normally located in the battery compartment and looks like this:

I believe your battery compartment is under the steps and the relay is mounted to the back wall behind the batteries. The positive cable from each battery set will go to the large post on the solenoid. This is the solenoid that cross connects the chassis and coach batteries. The small post is the one on the top in the picture.

Dave

moonlitcoyote · April 25, 2013, 08:13 PM

ok, that makes sense and I can get into the battery compartment tomorrow. If I find the right solenoid how do I measure it? Put red to the small post and black to ground and set voltmeter to 12v?

DaveVA78Chieftain · April 25, 2013, 08:24 PM

Yep.

You are looking to see if it has power to it resulting in it energizing thereby cross-connecting the 2 batteries.

Dave

moonlitcoyote · April 26, 2013, 12:18 PM

First, I really have almost no idea what to do with a voltmeter as far as where to set the switch so not sure if I did it correctly.

I first tested the batteries with the voltmeter to make sure I had it set to something that would give me a reading and I got 11.73 off one battery and 13.78 off the other house battery. The chassis battery gave me a reading of 0.63. So then I checked the small center post of the solenoid and I didnt get any reading at all, now my question is.. Was I supposed to put the ground on the solenoid also or just ground to anywhere?

moonlitcoyote · April 26, 2013, 04:19 PM

Actually I guess it should have been the other way around, because the other one started with wont start unless jumped.

DaveVA78Chieftain · April 26, 2013, 05:18 PM

MJ,
For reference, if you have 13.78 on house battery (BTW that indicates the converter is ON) but only 11.73 on the chassis battery (badly discharged) that means the solenoid is not ON (energized). If it was energized, you would have 13.78 on both sides of the solenoid.

Dave

moonlitcoyote · April 26, 2013, 05:30 PM

actually, that was the readings for 3 batteries. I have 2 house batteries, one house battery was 11.73 and the other house battery was 13.78. The chassis battery was dead due to the drain and was only reading 0.63

DaveVA78Chieftain · April 26, 2013, 07:17 PM

Hmm, thats odd. Both house batteries should be connected together in parallel so they should read the same.

Dave

moonlitcoyote · April 26, 2013, 08:47 PM

they were connected in parallel, when I did those readings. Then I took them out to get the chassis battery out to check the water level and I got the same readings from the house batteries when they were disconnected. Does that mean there is a problem somewhere?

DaveVA78Chieftain · April 26, 2013, 11:48 PM

My first guess is there may be a bad connector on the cable that went to the 11.73 house battery. It is resulting in a 2 volt drop in voltage between the 2 batteries. Both house batteries should have read the same voltage. Did the 11.73 house battery take a charge and hold it OK? We keep going off on tangents which confuses things

Dave

moonlitcoyote · April 27, 2013, 12:51 PM

I give up, I CANNOT trace these wires. Knowing what your looking for and actually being able to do it without tearing everything apart is a different matter. I am done.

M & J · April 27, 2013, 03:11 PM

Never surrender, never retreat.

Oz · April 28, 2013, 10:44 PM

Don't feel bad, MJ. When it comes to electro-gadgetry, I'm sitting right next to you in that boat. I'm pretty good at a lot of things but electrical systems just short-circuit my brain. I was just very luck that my lifeline was long enough to reach Dave B and he ever so gracious to grab it and make the trip up to bail me out of my sinking ship.

Take a breather, sometimes, that's all you need. Your brain will continue to mull-over everything you've learned and when it believes it has a handle on this... it will let you know. The subconscious mind is a powerful tool.