12v Constant DRAW

[honestbest333]

Hi guys,

I have something 12v draining my batteries overnight. I have everything shut off on the camper, and it still drains them over night. Just put in new batteries as well. Still drains them.

How do I start trouble shoothing this 12v electrical system to see what is causing the drain?

[IBcarguy]

Hey Honestbest333....did you ever figure out what was draining your batteries?

[DiskDoctr]

I've used this model in fuse slots for the larger size, like older vehicles, works okay for those 😉

I don't have the link handy at the moment, but I posted up the difference in draw of the original incandescent bulbs and the new LED bulbs. It's in here somewhere... 😉

[CA_Traveler]

My car has micro2 style fuses which is not the mini style and I didn't see that style adapter.

[SoundGuy]

CA Traveler wrote:
Nice useful tester however lacking some fuse sizes like micro and micro2 and others.

Seems Fuse Buddy offers a number of different versions, including this Fuse Buddy Pro which includes adapters for ATC and mini fuses.

[bigfootford]

Just a note....

If your fridge is running on propane and you have inadvertently switched the de-humidifier/anti sweat switch on it pulls a few amps.... Most fridges have them. Many folks do not even know that they have one.

Post the make and model or look up the feature yourself.

Jim

[CA_Traveler]

Yup Plus a light bulb in series with a shorted circuit is another diagnostic tool.

[MEXICOWANDERER]

A fifty watt incandescent light bulb and twin wires bridging a disconnected house battery makes a fine diagnostic tool. I've used one of these since the sixties. Cheap. Easy to assemble and bullet-proof reliability. It works dimmer and dimmer down to less than a quarter amp drain. A 12 volt LED lamp could then be substituted for micro leakage detection.

Leaves the hands totally free. No fumbling.

[CA_Traveler]

Nice useful tester however lacking some fuse sizes like micro and micro2 and others.

And be aware that a few circuits reset when opened and will not have the same draw when reconnected.

[DiskDoctr]

One of these is quite helpful to find draws and how much on each circuit.



I bought it here: https://www.amazon.com/305M-Fuse-Buddy-Mini-Tester/dp/B000W8FMXU

[MrWizard]

battery disconnect are handy for storage situations

BUT

you need to find your problem, start by checking the vent fans are operating, can be turned on off, a failed fan that looks OFF not running might actually be stalled or shorted and using power

next pull all the house DC fuses from the fuse panel
check your battery again the next day, still charged ? then it is one of the fused circuits
put the fuses back in one by one
watch for sparks

fridge ? is it a 3 way, 12v 110v lp,
make sure the 12v option is off
do you have an inverter ? did it get left on ?

truck camper ? trailer ? pop-up ? motorhome ?

[IBcarguy]

All these are good suggestions. Most TTs have a 12V kill switch to shut off when you aren't using the trailer. If you don't have one it's easy to install. But it sounds like you have a major draw if you are knocking down 2 fresh batteries overnight. Something is left on. As suggested, you gotta start looking, pulling fuses to isolate which circuit is on. Using a multi-meter is best but a simple 12V test light is good too. Someone mentioned the trailer brake breakaway switch being unplugged...that happened to me once long ago and it killed my batteries by the next morning.

[Sam_Spade]

I suggest that first you charge the battery up fully, then disconnect all the wires from one post and then see what has happened 24 hours later.

IF....the battery is still "full", then installing a true disconnect switch (or using the one that is already there) is probably the best solution because you should have one anyway.

If you somehow feel that you just MUST know what is doing the draining......then follow the other suggestions about meters and fuses.
But that likely isn't really necessary.

[EdTheEdge]

I am sure you checked this but once I left a l8ght on in my storage compartment and it took me 2 weeks of "battery" drain problems to find it.

[ktmrfs]

several things will be a constant draw unless disconnected.
1) entertainment system. most in the "off" position are really "standby" and draw enough current to drain a single 12V battery in several days
2) CO and propane detectors hooked to 12V

these alone shouldn't drain the battery overnight. but, if the battery is drained, and you think your going to charge it in less than 12 hours with the common WFCO charger, well, nope, won't get near full charge in that short time. yes, it is supposed to put out 45-55A, but seldom will do so, usually gets stuck at 13.6V and 10A or less charge current.

In any case, to keep batteries from draining, you need to either
a) install a battery disconnect switch
b) remember to turn off or disconnect the things that are always on