severe battery drain

[pawagan]

:' CAN SOMEONE OFFER ME  A  SUGGESION ON WHAT MIGHT BE THE PROBLEM? I have a 1954 GMC 4104
When my rig is shut down in dry dock for some 72 hours the battery runs completely down.
I have attempted to unhook everything that might cause the battery to drain, like the refrigerator , water heater, and everything else I can think of. I am at my wits end. THE BATTERIES HAVE BEEN TESTED, they were on a Snap on tester. PLEASE CAN ANYONE COME UP WITH AN ANSWER ON WHAT MIGHT BE GOING ON?

[Jerry Liebler]

Your battery may have lost most of it's capacity to store energy.  Are you talking about the start battery or a  house battery of deep cycle batteries?  If it's the start battery one total discharge may have destroyed it.  If it is the house deep cycle battery bank it may be restored by a long equalising charge.  One deep discharge will eliminate over 90 % of the storage capacity of a lead acid battery, due to sulphate build up.  You'll need to recharge then put an ammeter into the battery circuit to tell how bad the mystery load is. Then find it.
Regards
Jerry 4107 1120   

[Tony LEE]

How are your batteries connected - two 12v in series to give 24V, two 12V in parallel to give more capacity, One 12v battery ...

[ttomas]

 One of your batteries is probably shorted out. the jarring of the lead inside will cause it to settle and short out the battery. I have had one battery drain an entire bank rather quickly. Tomas

[TomC]

I would suggest charging the batteries fully, then disconnect them.  Come back in a week to see the state.  If they are still fully charged, then you have an electrical drain.  A battery cut out switch will help.  Better to find the drain. If one or more batteries are drained without being hooked up-time for new batteries. Good Luck, TomC

[gus]

paw,

I had the same problem with my "54 also but not quite as bad as yours.

There are a bunch of things on a 4104 that could possibly cause the drain. A quick way to find out if there is a drain is to disconnect all batteries then just touch one connector to a battery, if you get a spark you have a drain. Even a small drain will make a small spark. This can also be done with a voltmeter.

I took the easy way out and installed a cutoff switch on each battery-no more problems. Now I can use the switches to isolate any bank I choose for using or charging-never any more dead battery worries.

These "green knob" switches can be found at most farm supply stores and probably auto parts stores too but maybe at a slightly higher price. I get mine from JCW or my farm store for about $7 each. I own about 20 vehicles and have these switches on every one. They are great for when doing maintenance and save the day when something shorts out-like a starter solenoid!!

[compedgemarine]

my Eagle was originally set up with a cutoff switch on each of the three batteries. this fed each to a common bar that then went to a master cutoff switch. I assume this was so if one battery failed you could take it out of the system? when they are all off if a battery goes down it is that battery without a doubt. it also has a voltmeter with a switch at the batteties so you can turn each switch on and see the voltage in each battery.
steve

[gus]

comp,

That is pretty much what mine does except I don't have that nice big switch.

I've thought about getting one to eliminate having to go back and open the battery bay.

Where is it located?

[kingfa39]

charge the batteries and disconnect them for 72 hrs and see if they go down, if they dont the batt are good and you will have to go through the elec system and isolate the problem, its good to have a disconnect but things should not go down , my bus sits out there year after yr and they never go down, a small current draw somewhere will do it, i had one of the bay lights on all the time (bad switch) that caused that problem but it could be anything, just need to use the elei=mination process
Wish i could help more
Frank Allen
4106

[compedgemarine]

Gus,  on my Eagle there is a battery door on the curb side directly behind the rear axle. that is where the three individual switches and the volt meter are located. then when you open the rear engine door the main cutoff is to the right of the engine. dont know the logic behind it all unless as I said maybe to isolate out a bad battery?
Steve

[gus]

Steve,

All that makes sense. The individual swithces, as you say, can isolate any battery you like. Mine is set up the same way but I had to do it. I don't have a VM there but that is a very good idea also and I will be adding one soon.

The other switch at the engine must be to shut off elec power for a mechanic working back there without having to go around to the battery comp every time he wants power turned on or off. This is a very good idea and does save some steps.

[Chris 85 RTS]

Alternater diodes or the regulator can go bad and cause a parasitic drain on the batteries.  I agree that you have to isolate the batteries to see what is what.  If you want to use a voltmeter to test this, get one with a 10A or greater DC Current setting that is fused.  Connect this in series with the positive battery cable and everything else turned off.  You should see less than 1 amp current.

[DrivingMissLazy]

A one amp drain will drain a battery over a relative short period of time. I finally discovered what my drain was and was shocked to find that it was a dash mounted clock.
Power was not removed when the main disconnect switch was turned off. The clock actually ticked instead of just running and every time it ticked, it took a small surge of current. I finally found it by using a digital clamp on ammeter.
That is the only piece of test equipment I found that could help me find it. An inline 10 amp ammeter would not have shown the small current drain it was causing and it did not cause an arc when the battery terminal was removed and then re-connected.
Richard

Alternater diodes or the regulator can go bad and cause a parasitic drain on the batteries.  I agree that you have to isolate the batteries to see what is what.  If you want to use a voltmeter to test this, get one with a 10A or greater DC Current setting that is fused.  Connect this in series with the positive battery cable and everything else turned off.  You should see less than 1 amp current.

[pete81eaglefanasty]

 I also have a Eagle, and have the three switches in the curb side compartment, We had a battery drain like you point out. We found out that two of the switches had a slightly ground to them. after replacing the switches, no more dead battery.

                Pete & Jean
                   Fantasy

[buswarrior]

A nasty parasite:

The stock PA system has been known to be a longer term culprit. Pull the plug wires out of the amp to stop. plug back in to entertain the kids....

happy coaching!
buswarrior