Testing for battery drain

richard

New member
Jul 3, 2003
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I have a ongoing drain on engine battery that needs trouble shooting.

I have a meter but not sure how to proceed.

Meter shows voltage between negitive post and ground.

Thanks!
--
Bukzin
1977 Palm Beach
2006 Monaco Diplomat pusher
 
You don't say whether it's the engine battery or the house battery.

Assuming it's the engine battery, remove the positive lead from the battery. Connect the meter leads to the negative battery post and to the end of the negative cable. Put your meter on D.C. amps (or miliamps) so that you see a reading indicating current flow or a drain.

Pull one fuse (fuse box is behind the glove box) at a time until you see no current flow on the meter. That will show you which circuit is causing the drain.

Emery Stora
77 Kingsley
Frederick, CO

Emery

>
> I have a ongoing drain on engine battery that needs trouble shooting.
>
> I have a meter but not sure how to proceed.
>
> Meter shows voltage between negitive post and ground.
>
>
> Thanks!
> --
> Bukzin
> 1977 Palm Beach
> 2006 Monaco Diplomat pusher
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Oops. You did say the engine battery.

Emery Stora

>
> I have a ongoing drain on engine battery that needs trouble shooting.
>
> I have a meter but not sure how to proceed.
>
> Meter shows voltage between negitive post and ground.
>
>
> Thanks!
> --
> Bukzin
> 1977 Palm Beach
> 2006 Monaco Diplomat pusher
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Also there should be 0 volts between the negative post and ground. What are you using for ground?
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Emery, if he removes the positive battery cable and does not replace it
after the meter is in place, he won't see any meter movement unless he has
his meter set for ohms. If he has it set for ohms and the positive cable is
in place, and his meter isn't well protected, he is liable to have a very
worthless meter shortly if he has a big drain. Just sayin'.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

Also there should be 0 volts between the negative post and ground. What
are you using for ground?
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

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> You don't say whether it's the engine battery or the house battery.
>
> Assuming it's the engine battery, remove the positive lead from the battery. Connect the meter leads to the negative battery post and to the end
> of the negative cable. Put your meter on D.C. amps (or miliamps) so that you see a reading indicating current flow or a drain.
>
> Pull one fuse (fuse box is behind the glove box) at a time until you see no current flow on the meter. That will show you which circuit is
> causing the drain.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO

Hey Emery, I think you have a small error in your posting. You have him removing the "positive" cable and installing the meter in series with the
"negative" side.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Ken
You are correct. I did make a big mistake. I should have said to put the meter in series with the POSITIVE post.

Emery Stora

>

>> You don't say whether it's the engine battery or the house battery.
>>
>> Assuming it's the engine battery, remove the positive lead from the battery. Connect the meter leads to the negative battery post and to the end
>> of the negative cable. Put your meter on D.C. amps (or miliamps) so that you see a reading indicating current flow or a drain.
>>
>> Pull one fuse (fuse box is behind the glove box) at a time until you see no current flow on the meter. That will show you which circuit is
>> causing the drain.
>>
>> Emery Stora
>> 77 Kingsley
>> Frederick, CO
>
> Hey Emery, I think you have a small error in your posting. You have him removing the "positive" cable and installing the meter in series with the
> "negative" side.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
You can perform the same thing with a test light between the negative post
and negative cable and pull fuses like emery said until light goes out.

Sully
77 eleganza 2
Seattle

> Ken
> You are correct. I did make a big mistake. I should have said to put the
> meter in series with the POSITIVE post.
>
> Emery Stora
>

> >

> >> You don't say whether it's the engine battery or the house battery.
> >>
> >> Assuming it's the engine battery, remove the positive lead from the
> battery. Connect the meter leads to the negative battery post and to the
> end
> >> of the negative cable. Put your meter on D.C. amps (or miliamps) so
> that you see a reading indicating current flow or a drain.
> >>
> >> Pull one fuse (fuse box is behind the glove box) at a time until you
> see no current flow on the meter. That will show you which circuit is
> >> causing the drain.
> >>
> >> Emery Stora
> >> 77 Kingsley
> >> Frederick, CO
> >
> > Hey Emery, I think you have a small error in your posting. You have
> him removing the "positive" cable and installing the meter in series with
> the
> > "negative" side.
> > --
> > Ken Burton - N9KB
> > 76 Palm Beach
> > Hebron, Indiana
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
I assume a small (maybe very small?) amount of current leakage is normal?

If so how many milli-amps?
--
Bukzin
1977 Palm Beach
2006 Monaco Diplomat pusher
 
Radio pre-sets draw miliamps. The refrigerator and furnace if they have
circuit boards that light the burners instead of pilot lights, about the
same. But, they all add up to a slight drain over a few weeks that take a
battery charge down so that they won't start readily. Use a battery tender
type of charger, or disconnect the battery ground cables.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> I assume a small (maybe very small?) amount of current leakage is normal?
>
> If so how many milli-amps?
> --
> Bukzin
> 1977 Palm Beach
> 2006 Monaco Diplomat pusher
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Lot of unknowns to answer that question.

Assuming its all completely stock, there should not be much if anything that would draw off the engine battery.

The minor draws are usually a clock or radio presets on a newer dash radio or CD player. Fuel Injection computer settings if you have a FI set up. A
hardwired smoke/CO detector that was wired into the engine battery instead of the house battery.... Aftermarket radio that is wired to 12 v Hot all
the time instead of keyed hot.

In addition to pulling fuses and watching the meter or light, Id look for the easy stuff. When its dark, go out to the coach and see if any lights
are on. Gen compartment, closet, radio, bath fans etc. Then listen, if you can hear anything running that should not be when everything is off, and
you are not plugged into shore power.

I had a parasitic draw on a car once that gave me fits for 3 months. Turned out it was a dome light that would come on and off intermittently due to
one door switch. Sometimes the switch would close when the door was closed, other times it would not. Other times in the middle of the night the
light would come on. I only realized it when I looked at the car one night when it was dark out. I lubed that switch and the problem went away.
When I tested those circuits everything checked out, because the switch just happened to be closed that time when I tested.

--
77 Royale, Rear Dry Bath. 403, 3.55 Final Drive, Lenzi goodies, Patterson carb and dizzy.
Mid Michigan
 
Thanks for the tips guys.

Gave up and took it to a shop. He said even though meter showed 10+ volts
amp meter showed draw of 0.2, not enough to stress over.

Replaced battery as it had a dead cell.
--
Bukzin
1977 Palm Beach
 
Actually .2 is a lot of draw. GM spec for maximum draw is .02 . At that .02 spec GM says a car will start after sitting a maximum of 30 days. You
are at 10 times the maximum. I would go chase it down and eliminate it.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
What Ken said. Make sure of that decimal point with the technician, if you call him that. A .2 amp draw is 200 milliamps, 1/5 of an amp...enough to
drain the battery sufficiently between runs to cause that dead cell. Also, the amount of current drain from the vehicle systems needs to be measured
with a fully charged battery. Values can change with a low state of charge or a charger set for a high current that may bring in AC ripples into the
electrical systems.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.