Need advice on troubleshooting battery drain

[jmcboost]

My battery lasts about 3 days on a good charge, and then I go to start it and there is barely enough juice to crank the engine. It has done it on two other batteries and the one in now is a month old. I need advice on the best way to troubleshoot this problem. I have a good multimeter and good wiring knowledge. Where should I start first?

[bluepearl]

TSRM available on line

[steve_mk3]

1-Check to make sure your charging system is working
2- Make sure you have a good battery to start with.
3- Make sure it is charging/maintaining a charge when it is running
3- If the car is charging and a good battery then you may have soemthng wrong that is discharging the car while it is turned off.
4- Check to see how much current is discharging with the car turned off, if it is excessive remove the fuses one by one to find the link that is draining off the battery
5- troubleshoot the link identified in #4

Good luck

[jmcboost]

What is the best way to hook the multimeter up to the electrical system to measure the current when the car is off? Do you have a diagram? Thanks for the help.

[steve_mk3]

Not sure what year your car is so the cygnusx1 site may have the correct wire diagram for your car.

I had a similar problem, when I turned the car off and had a multimeter placed b etween the + and - terminals on the battery your could watch it count down from like 14.5 to 12 in a couple of minutes. I isolated the circjuit that was causing the excess drain and went from there.

This is a pain in the ass, but I dont know of any other way.

Steve

[bo3232000]

Unhook the negative wire on the battery and put a test light inline with the lead.I usually put the probe on clamp however it will stay and the clip on the battery...Start pulling fuses one at a time and when the light goes out you found the draw...Whatever circut it is in conjunction w/ is where the draw is being created..pull a fuse and if light stays on put it back,then the next and so on.....Hope this is helpful to you and all for diagnostic ideas...

[pimptrizkit]

Unhook the negative wire on the battery and put a test light inline with the lead.I usually put the probe on clamp however it will stay and the clip on the battery...Start pulling fuses one at a time and when the light goes out you found the draw...Whatever circut it is in conjunction w/ is where the draw is being created..pull a fuse and if light stays on put it back,then the next and so on.....Hope this is helpful to you and all for diagnostic ideas...


i was going to say that but with a multi meter..

[steve_mk3]

i was going to say that but with a multi meter..


Yes use a meter. Some current drain is normal like for the clock, radio, ecu etc so just finding a circuit that has current flowing to ground wont neccisarily mean you found the correct cirucit. You need to find the circuit that has drain that is not supposed to.

Steve

[Adjuster]

Start with the fuses in your engine bay, then move to the fuses in your car. (Easy that way, and It's likely something in the engine bay if your draining power that fast.)

Remember to check the fusable links too. (Huge fuses basicly.)

Once you find the fuse that when removed takes the load away, then go to the part that is fused, and check for signs of damage. Check the wires leading up to the part that you can see as well. (No need to buy a expensive part when you can see the harness wires have been crushed by a careless prior owner, or auto accident with crappy repairs to your wires before you owned the car.) A short is a short, in the wires or in the part, it's just a "leak" of power to ground. (However some would say the electrons are actually moving the other way around, but you get the point.)

Good luck, this takes time, so I hope you find your short on the very first fuse pull... (This can be easy if you see impact damage, or some old repairs, look for the parts that are in that area, and the wires in that area. Or if somone wired up a stereo or alarm, those are all suspect area's too.) Same goes for SAFC etc.

[jmcboost]

Thanks for the help. I will hopefully get something figured out soon.

[pimptrizkit]

i belive parasitic draw should be some where around 25-50ma

if your pulling in 100-400ma, it should be easier to find the problem..


a nice one i have had before one a trunk light that had grounded so the light stayed on, but you couldn't visualy see it, and be checking the fuse, then checked the other light, and checked ewd and found one last night in the trunk,pulled the bulb, and our draw went away..

[jmcboost]

I think I found it. It looks to be the dome light. I am testing now. How do you test or hook up your multimeter for "perisitic" current draw, or whatever that is.

[Nick M]

What is the best way to hook the multimeter up to the electrical system to measure the current when the car is off? Do you have a diagram? Thanks for the help.
Not to sound mean, but if you don't know this, don't work on your car.

[pimptrizkit]

and some one didn't teach you nick?



you will need to set it to check for amps, and then need to more then likely move your red lead over to the A side.

dissconnect the negitive lead on your batterie, then hook a jumper wire up between the post and the cable, this way you dont blow your meter when you hook it up and every thing re-powers it self drawin peak current for a second... ask how i know..

ewd/electrical wiring diagrams can be found here...
http://www.cygnusx1.net/supra/index.html

[Nick M]

and some one didn't teach you nick?


Not on the internet.

I learned what parallel and series circuits are for free in public schools. The advice still stands. There is no shame in paying somebody that knows how to do it for you.

[spipedong]

In case it wasn't the dome light... Got Power Seats?

Mine were draining my battery randomly. Then on a long trip the seat started smoking and burning, so yeah.

[jmcboost]

Nick M, You are the smartest man alive!!!!

Is that what you wanted to hear? I asked a question, and if you went to public school, you know what they say, "no question is a stupid question." So if you don't want to help, please don't post. Thanks. :icon_bigg



Other than that, thanks for the help guys. I think I am getting close to figuring it out. I'll let you know the results.

[jmcboost]

In case it wasn't the dome light... Got Power Seats?

Mine were draining my battery randomly. Then on a long trip the seat started smoking and burning, so yeah.


That's kind of funny, good thing your car didn't burn down.

[Nick M]

Nick M, You are the smartest man alive!!!!

Not hardly. I just have a lot of experience doing electrical/electronic work specifically on Toyota systems.


Is that what you wanted to hear?

Did I ask a question? No. I told you if you don't know how to use a multimeter then just don't do it. It isn't worth fucking up the meter, or your car. But hey, no problem, you are on your own. There are plenty of patient spoon feeders on here for you.

[jmcboost]

Nick M, Did I ever say I didn't know how to use a multimeter? Thanks for your non help! I think you read into to things way to much. As much time as you have spent on this thread, you probably could have helped me solve the problem by now. All I ask of you now is to please not post on this thread unless you have positive help for me in solving my battery drain problem. Thanks (BTW, positive help to me is helping me fix the problem with my own hands, and knowledge and help from my supra buds. )

[Nick M]

Nick M, Did I ever say I didn't know how to use a multimeter?



What is the best way to hook the multimeter up to the electrical system to measure the current when the car is off?

edit: Sorry I wasted your time. I am sure somebody some where will show you how to hook up the leads in series.

[jetjock]

"I have a good multimeter and good wiring knowledge".

"What is the best way to hook the multimeter up to the electrical system to measure the current when the car is off? Do you have a diagram?"

"How do you test or hook up your multimeter for "perisitic" current draw"

"Did I ever say I didn't know how to use a multimeter?"

You didn't have to because it's obvious you don't. One of the most common uses of a meter and one of the simplest tests known in auto-electrical troubleshooting had to be explained to you. Nick may be blunt at times but he *was* trying to help you and his advice was/is completely valid.

[JZ_killa_t68]

Sorry if I'm straying away from the current (no pun intended) conversation, but do you have an aftermarket alarm installed? I've seen those suck a battery dry before.

Josh

[jmcboost]

You guys that are not helping are beeing Jackass's. I used to read your posts all the time (Nick M and Jetjock) and I learned a bunch. Now you just want to get on here and start an arguement with me over whether I know how to use a multimeter or not. Grow up!!! Nick M. are you really 33, you act more like 13. Trying to prove to everyone that you know more than them. There is more than one way to test for current draw or a short, I am pretty sure you could test the continuity from the positive and negative leads from the car with no battery hooked up, or I could use a logic probe and test for wires shorted to ground, but what I was asking is what way do you think is best. So please, for the third time don't post unless you have some mature and helpfull info.

[jmcboost]

Sorry if I'm straying away from the current (no pun intended) conversation, but do you have an aftermarket alarm installed? I've seen those suck a battery dry before.

Josh

Yes I do have an aftermarket alarm, I am looking at that also, but I think I have it narrowed down to the dome light. Thanks for beeing helpfull. Apperently posting on here is sometimes a contest about who's right and not a helpfull community of Supra bretheren. :icon_bigg

[suprageezer]

I gotta agree with JMC on this one I see way to many self imolated braniacs respond to questions from young folks asking for help and knowledge. Honestly if someone posts a question on Supramania either help, answer or keep your freaken insults, bragging, and basically nothingness responses in your mind, which is where they belong anyways. Just an FYI EVERYONE LEARNED ALL THEY KNOW FROM SOMEONE ELSE.....PERIOD.
Teachers are cool, come in all flavors, sizes, and intellects.

On the battery have you positivly made sure the battery is good? the alternator is good?. One easy simple test to determine this is with the car running, disconnect the negative battery cable. If they car continues to run the alternator is good since it is generating enough electricity to run at an idle. It can also indicate a weak or bad battery since it runs at an idle but goes dead after a period of time, meaning the battery isn't taking the proper charge to keep itself charged. If it died when you removed the Negative cable the alternator is either bad or weak and can't keep the car running at an idle.

Rick

[jetjock]

I was only pointing out the hole he dug himself into. By doing so he came across as a fool. And you'll note I didn't respond to this thread before even though I could've easily told him all the tricks mentioned and a bunch more. Why didn't I? Because he obviously wanted his hand held. Five minutes with Google and he'd have learned all he wanted to know.

As for your "help", disconnect the negative battery cable? Lol! You gotta be kidding me! Are you actually suggesting someone do a deliberate load dump on an EFI equipped vehicle? Load dumps have the potential (pun intended) to destroy every piece of electronics in the car. If everyone learns from someone else (BS btw) learn this: he'd be a fool to listen to that advice. You'd better not quit your day job...

[jmcboost]

I was only pointing out the hole he dug himself into. By doing so he came across as a fool. And you'll note I didn't respond to this thread before even though I could've easily told him all the tricks mentioned and a bunch more. Why didn't I? Because he obviously wanted his hand held. Five minutes with Google and he'd have learned all he wanted to know.

As for your "help", disconnect the negative battery cable? Lol! You gotta be kidding me! Are you actually suggesting someone do a deliberate load dump on an EFI equipped vehicle? Load dumps have the potential (pun intended) to destroy every piece of electronics in the car. If everyone learns from someone else (BS btw) learn this: he'd be a fool to listen to that advice. You'd better not quit your day job...


This is my Supra Google!!! We all have one thing in common, the MK3 Supra, so help someone out instead of telling them not to do it, or argueing with them. Nick M and Jetjock you are both smart guys, I needed your help and I didn't get any from you.

[Nick M]

Now that this thread is hijacked....that isn't true. You said you didn't know how to do the test, I said find somebody that does, there is no shame in paying a mechanic, and you took that personal somehow.

[frank]

"One easy simple test to determine this is with the car running, disconnect the negative battery cable. If they car continues to run the alternator is good since it is generating enough electricity to run at an idle. It can also indicate a weak or bad battery since it runs at an idle but goes dead after a period of time, meaning the battery isn't taking the proper charge to keep itself charged. If it died when you removed the Negative cable the alternator is either bad or weak and can't keep the car running at an idle."

I know I'm new here and probably should just keep my mouth shut, but please don't do this. Never mind the effects it may have on electronics, it isn't a reliable test, hasn't been since the days of generators. Sometimes an old alternator will have enough residual magnetism in it's armature to generate enough current to keep an ignition system firing and sometimes it won't. Alternators need an exciting current to produce electricity.
If you want to test your alternator hook up your multimeter with the car running and look for 14-15 volts output from the alternator. Load it up with lights, blower, wipers, stereo, defrosters, etc., and see how it keeps up. (Chances are it won't keep up at idle, but it shouldn't completely fall on it's face either.)
Load testers for batteries are available quite reasonably priced.

[pimptrizkit]

well frank, thats a good solid point about alternator's

i do remember that modern computers can control the out put of an alternator by the current at the armature i belive..


the way i was taught to test a battery was to load it, should crank engine for 15 seconds and not fall below 9.6volts while cranking and return to 12.4(12.6 if new batt)

[suprageezer]

You've got to be kidding me you think electrical engineers at Toyota didn’t think people would be disconnecting the negative battery cable? Give me a break I have never Not Once ever actually seen a car damaged due to the negative cable being disconnected. It's just another stupid urban myth perpetuated by really intelligent people who heard it from some one or they read it somewhere so it must be true. I just called two friends that own auto repair shops and both said they have heard this also but have never actually seen any damage done by this method of checking. I then did a Google search and see many sites with your advice but not one said Negative cable, they all said battery cables. I believe your info is put out by those unscrupulous auto repair shops and by those that need to cover themselves as far as liability goes. Disconnecting the Positive Cable while the engine is running can and has many times led to DEATH. Just how many electrical systems have you personally damaged by disconnecting the negative on the battery? If it's zero, your repeating either what someone told you or you read somewhere. I would say it's better to give advice you have experience with than to pass on what someone told you or you read somewhere. My advice is sound and you would find it's one of the first things any shop would do when someone complains about starting and charging problems not ECU problems. Remember I said the negative not positive which could cause a surge and possibly damage something electrically. So wizards of ALL tell us all how you would go about replacing a battery if disconnecting the negative can cause damage? My cars and van have never been damaged by this method and I have personally done this a few times to check. How could it be they survived but others died? Then of course I could be wrong
Rick

[SupraDerk]

You've got to be kidding me you think electrical engineers at Toyota didn’t think people would be disconnecting the negative battery cable? Give me a break I have never Not Once ever actually seen a car damaged due to the negative cable being disconnected. It's just another stupid urban myth perpetuated by really intelligent people who heard it from some one or they read it somewhere so it must be true. I just called two friends that own auto repair shops and both said they have heard this also but have never actually seen any damage done by this method of checking. I then did a Google search and see many sites with your advice but not one said Negative cable, they all said battery cables. I believe your info is put out by those unscrupulous auto repair shops and by those that need to cover themselves as far as liability goes. Disconnecting the Positive Cable while the engine is running can and has many times led to DEATH. Just how many electrical systems have you personally damaged by disconnecting the negative on the battery? If it's zero, your repeating either what someone told you or you read somewhere. I would say it's better to give advice you have experience with than to pass on what someone told you or you read somewhere. My advice is sound and you would find it's one of the first things any shop would do when someone complains about starting and charging problems not ECU problems. Remember I said the negative not positive which could cause a surge and possibly damage something electrically. So wizards of ALL tell us all how you would go about replacing a battery if disconnecting the negative can cause damage? My cars and van have never been damaged by this method and I have personally done this a few times to check. How could it be they survived but others died? Then of course I could be wrong
Rick

Tsk tsk...load dumping = bad.

When you remove the positive connector, if you happen to be touching the metal part of connector and it happens to still be making contact with the positive terminal...you are the ground and you complete the circuit. In short...you are in a lot of pain or are possibly dead.

When you remove the negative connector, you take away the reference voltage for the battery and the load on the alternator. When you do this there is a "load dump" on the alternator. Since the alternator was energized to be running with the previous load of the battery, it still retains this energy when the load is dumped from the battery. It takes some time for the regulator insinde of the alternator to realize a load is missing and compensate for it...so the alternator's output is high for a bit.

If the output of the alternator is TOO HIGH...you can say bye bye to any electrical component in that circuit.

[Nick M]

http://www.autoshop101.com/forms/h8.pdf

Page 9 of 21 please. This is written by the Toyota electrical engineers, not an "unscrupulous auto repair shops".

Then explain why you can and that is wrong.

[Nick M]

I can google search aliens at area 51, so you must seperate the BS from not.

[tropical 87t]

Something similar happened to me after I did a engine rebuild on my 87t. My battery lasted only one day. I looked for a short for weeks, pulled one fuse at a time and test for draw with a multimeter on each. Just by chance, I found that my rear defroster and mirror heaters were on constantly. So I unplugged them but never found out why it happened. Now I can't use the defroster. Or mirror heaters. But I live in Florida.

[jmcboost]

I can google search aliens at area 51, so you must seperate the BS from not.

Way off the subject of battery drain but, I bet you could find a bunch of stuff about "aliens at area 51" on an area 51 forum.

[drjonez]

..When you remove the negative connector, you take away the reference voltage for the battery and the load on the alternator. When you do this there is a "load dump" on the alternator. Since the alternator was energized to be running with the previous load of the battery, it still retains this energy when the load is dumped from the battery. It takes some time for the regulator insinde of the alternator to realize a load is missing and compensate for it...so the alternator's output is high for a bit...

nearly dead on. happens when you yank the neg. terminal too. think of the battery as the "load" for the alternator....remove it and voltage spikes WAY up and then the regulator steps in.

sure, all OEMs test for it (heck, that's what I DO), but did the mfg of your sweet radio test for it? probably not. did apexi test the SAFC for it? probably not. FWIW, load dump is one of the most severe electrical tests performed on vehicle electronics....