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Parasitic drain, any ideas?

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drain
2K views 14 replies 7 participants last post by  Hans 
#1 ·
Ok,
Just finished redoing alot on the truck. Parked it Sunday and now Wedneday its dead, this is the second time its happened since the radio was "professionally" connected. (on a brand new yellow top)
now the friggin radio shop goes under, so I can't have them check anything

Here's what wired up
Lights, radio, amp, reverse light, winch, Viper alarm
I guess its the radio.....
I have ordered the painless dual battery setup and hope that will fix the problem

Is there a way to try to "measure" the slow draw?? or any way to figure out why it draining?

Thanks
 
#3 ·
Disconnect the NEG side of the battery. Install a test light (make one from any small 12v lamp if you have to) between the NEG terminal on the battery and the (now loose) NEG battery cable for the car.
(don't start the car or anything with this rig in place) The brighter the light the more draw you have.
Start pulling suspect fuses (radio, clock, amp. etc). Once you find the big draw the light will dim. With the clock and such there will always be a little draw, but this will allow you to pin point if it is the radio, or the amp or whatever as you will able to see it in the "test lamp". Disconnect them independantly until you get a dim light and it will give you a direction to head.

Good backyard trick for those without a multi-meter.

Check they wired the remote turn on for the amp to the trigger wire from the head unit, otherwise your amp might be on all the time.
 
#4 ·
From experience, check that the amp is in fact shutting off when you power down the truck. Some less talented installers will just run a constant-hot line to the amp as well as the power-on connections, instead of running the proper switch lead from the head unit back to the amp.

-Hans
 
#5 ·
A dual battery cross over won't cure your problem, it would just allow you to start the Rover without getting out the jumper cables, but you'd still be killing battery #1 all the time and it won't last if you do that. You gotta fix the problem, not cover it up. :)

Follow-up Post:

Hans said:
Some less talented installers will just -Hans
I could write a book on what I've seen from stereo and alarm guys....
:eek:
 
#6 ·
ECR said:
A dual battery cross over won't cure your problem, it would just allow you to start the Rover without getting out the jumper cables, but you'd still be killing battery #1 all the time and it won't last if you do that. You gotta fix the problem, not cover it up. :)

Follow-up Post:



I could write a book on what I've seen from stereo and alarm guys....
:eek:
my brother has several friends who work at best buy car installation center, i would not trust these guys to add winshield wiper fluid to my car!
 
#7 ·
I have the exact same thing. I never was able to figure out what is causing it. My truck was originally a communications vehicle and I had to remove about 40 pounds of wires. I gave up and just installed a battery cut off switch. good luck!!
 
#8 · (Edited)
Its good to have the ECR experts on board, I have enjoyed reading your posts on all the threads.
Yes, I did plan to address the problem not cover it, but It will be nice to have the extra battery just in case. Your test light idea was exactly what I was thinking would work

I bet its the radio also, I did check the amp previously and it seems to be turning off with the remote lead as it should. I did wire the radio so it does not turn off with the ignition. But I have made sure its off lately.

I have one more amp to install, I will have another stereo shop check everything again.
Thanks all
 
G
#10 ·
The test lamp is a great start, but if it doesn't give you the results you're looking for a quick trip to Radio Shack - or most any hardware store - can get you a cheepie multimeter to actually check the current drain.

I had a mystery drain start up all of a sudden ... single bad diode in the alternator was causing a roughly one amp drain.

ECR's description of the test procedure is great, the meter will just let you measure it.
 
G
#12 ·
Yup, like Mike said

- turn everything off inside the car.
- disconnect the negative terminal.
- be sure that your meter (a) is fused for "amps", and (b) is set for a range > 10 amps or so.
- connect the black lead from the meter to the negative battery terminal and the red lead to the
(now disconnected) negative battery cable.
- read the current draw from the battery on the meter...if the number is small, you can adjust the range
on the meter ... assuming its not a fancy auto ranging meter here.
- report back :)

KAA
 
#14 ·
Ok,
I charged the battery, but didn't have time to get out the multimeter.....but I checked the radio
the amp is off but the XM box (the alpine xm ready unit has the external tuner)
it has very hot! Radio is off, do you think that stupid little tuner has enough draw to pull down an optima in 3 days?
 
#15 ·
It all depends on how much amperage it is drawing, but if it's drawing a couple amps and you're not driving enough to fully charge the battery..... it's possible.

-Hans
 
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