What's the best way to find a power draw??

Seems the battery is slowly draining and I can't seem to find the current draw. What's the best way to attack this problem???

 

use could use a amp meter , un hook neg cable an hook in series. pull one fuse at a time untill your draw is gone or use a test light same way.

 

I've got a voltage meter. Can you explain the "how to hook in series?"

 

unhook the bat cable. hook one probe to bat and one to bat cable ..set it on amps and see what the draw is..like i was saying take one fuse out at a time.if still their put fuse back in. also if no luck with the fuses , unplug alt. sometimes they can cause a draw if they are bad..

 

Don't know if you even have one but the "memory" circuit of a "modern" radio will show a draw and/because it's hot al the time.

Could just be a marginal/bad battery too...

 

Good advice, but to make it easier on yourself grab a 12 volt buzzer like a seatbelt warning. Disconnect one battery cable and hook the two wires from the buzzer in between the battery post and the cable you just removed. Start pulling fuses one at a time until the noise stops. Works like a charm.

 

This usually shows up when the car isn't being used alot [as in most hot rods]. If the batt terminals are easily got at, put an inline disconnect switch on the power terminal [usually positive], these are cheap to buy at marine shops. Boats have them for the same reason.

 

I've always used a voltage meter or test light, but the buzzer sounds like a great idea! Start yankin' fuses!

In all my vehicles I run a negative terminal disconnect (~$10) or a disconnect switch (~$30) mounted remotely depending where the battery is located. If the car is going to sit for more than a couple of days or so, the switch gets turned off...just peace of mind.

 

I've got the battery disconnect. I just figured if I go out of town for a couple days WITH the car, I don't want it to die on me. Just in case. I'll try the buzzer idea. Thanks guys.


speedy

 

i've had solenoids go bad, let the starter draw ever so slightly and kill my battery, also had a bad brake light switch leave the lights on all day, did the same.

 

I like the "sound" of the buzzer trick! This way you dont need to crawl out from under the dash every time you pull a fuse to see if the amp draw is gone or if the test light went out!

 

Clean the top of the battery. If it's dirty it there can be about a 5 amp drain.
Disconnect the negative cable and see if it drains by itself. If so, bad battery.
Check the brake lights, switch might be stuck.
Keep trying everything else.

 

Don't know your charging system, but I've seen quite a few GM one wire alternators drag a battery down over time. Glad to help with the buzzer deal. I've been using it for years. Sometimes it's real handy when you've got your head up in behind the dash and it's hard to see the meter.

 

Is there a 'buzzer' style available on the market place?

 

the first thing that I would check is to disconnect the altinator, ALL diodes have some degree of leakage (voltage coming back across them) the altinator has a

diode trio (three diodes in it)
just thought I'd get my 2 cents worth in on this discussion, I really like the seat buzzer Idea, even an old dog like me can learn a new trick every once in awhile

 

bttt

 

You should post trhat "buzzer" idea in tech week .I love it.I like doing under dash and minor electrical work but I really get tired of looking out at that test light sometimes.The buzzer(HMMMMMMMM how'd that happen?)is a neato,cheapo,easyo,idea.
Now will someone tell me how to stop shouting ?LOL
T.OUT

 

Anyone know if there is one available?

 

first put a ammeter between the battery post and hot cable- see if it's drawing- if it is, let it hooked up, and keep unplugging your harnesses until the ammeter goes to zero- that isolates what area it is in

typically there are 4 harnesses- dash/interior, rear lighting, front lighting/horns, and engine/accessories- if unplugging the lighting harnesses and engine harnesses still gives a draw, it's in the dash harness

you may have to jumper 12v to the fusebox somehow, to check the engine harness- as disconnnecting that kills the main power input to the fuse box

we had a '66 Chevy that drove us nuts with that same problem- turns out the previous owner kept one cinder block in the trunk to put his bumper jack on for height while jacking- the cinder block wore through the tail light harness and had it shorted to ground, draining the battery

also another friend had a lady with that same problem in her car- her high heel wore through the rug on the driver's side floor, and wore a wire bare and shorted it