I have a battery draw problem, where to start looking???

[69wannabe]

I have been having some battery issues since last fall but I just thought it was the batteries I was putting in (I had some used one's laying around that were decent) anyway I went and bought a new group 27 1000 cranking amp battery and it's been doing ok since then but I keep the battery tender on it most of the time too so it's really hard to tell. So the other nite I didn't hook up the battery tender and the next day it would not start. It turned over a little bit then nothing. Battery was weak so I put the battery charger on it and after a couple of min's it fired right up. So now I hooked the tender up and the battery cable off and charging it that way. So I have never ran into this except on my jeep grand cherokee and it was a bad latch button not cutting my dome light's off that was killing the battery on it. My car doesn't have the light package so no trunk light or map light or glove box light or little light over the ignition switch and etc... My clock has been rebuilt and I do have an aftermarket radio in the car. My meter has a spot for 10 amps and milli amps so what number would I be looking for that would be normal or excessive and what would I try unplugging to get rid of the battery draw I am having?  I know you should have a good answer on this Pete!!! 

[Pete in NH]

Hi,

Charge up the battery with your battery charger with the negative battery cable disconnected. Then use the 10 amp position on you meter to see if there is a sneak current draw. With the meter in the 10 amp position, put the positive meter lead (red) on the negative battery post. Then put the negative meter lead (black) on the negative battery cable battery post clamp. If the meter reads any thing in current there is something turned on in the car. I would then start pulling fuses out of the fuse block one at a time until the current reading goes away. This will give you an idea of what circuit to start looking at.

If you don't know how to set up you meter to the 10 amp DC scale post a picture of it so I can tell you how to do that for your meter.

[b5blue]

Be careful some aftermarket stereos will blow if you remove ground and power through accessory and/or main power feed is still hot. 

[69wannabe]

Got battery fully charged and pulled the negative cable and checked between the cable and post with my meter on the 10 amp scale and it read .017/.018. I was thinking maybe my alternator may be pulling it down but the reading is the same with it hooked up or if it is unhooked. There should be some draw since my clock is running when the battery is hooked up but i'm just not sure how much it should be pulling on the battery.

[Pete in NH]

Okay, if that .017/.018 reading is correct, that is about what I would expect from an electronic clock.That reading is 18 milliamps or 18 thousandths of an amp. That is very little current and a group 27 battery should hold that up for a very, very long time.

When the car is running, what is the voltage across the battery? Also, if it is still connected what is the dash ammeter showing. There may not be a current draw from the battery when the car is not running, it may never be charging the battery other than from your battery tender. The battery tender will take a very long time to recharge the battery when using the battery to start the car.

[69wannabe]

I had the ammeter converted to a voltmeter so the actual ammeter wires are bolted together and wrapped with e-tape. When the battery is fully charged the gauge shows 14+ volts but when it is slightly weak it doesn't charge that good. I'm gonna take the alternator and get it checked by my regular alternator guy and see what is up with it. There isn't really anything else that would be on that would cause a draw that I can think of. Maybe the alternator is my problem and that is an easy fix for me!!!

[69wannabe]

Well I left the battery unhooked for a couple of days and no battery tender hooked up and the voltage was still in the 13 volt range. Put my load tester on it and held it for 10-15 seconds and it never dropped below 11 volts so battery seems good. Pulled the alternator and am going going to drop off at my local alternator shop and let him check it out. Hopefully I can get this fixed up.

[69wannabe]

Got the alternator checked out today and it is putting out 75 to 80 amps at 14 volts. Now there is really nothing to keep my battery from charging except for where the wiring goes through the bulkhead connector. The ammeter is bypassed and the red and black wire are bolted together behind the instrument cluster. The alternator I am using is a one wire powermaster and the regulator does not excite until the stator is turning. One question is can I just run me a new wire from the battery straight to the alternator and put me an inline maxi fuse with maybe an 80 amp fuse in there and leave my factory wiring hooked up too??? I know I have to have battery voltage going inside to the black wire since it feed my ignition switch and a few other items and also run out to the alternator. Or do I need to run a new wire from the battery into the dash and tie it into the black wire and then run a new wire from there to the alternator with an inline fuse between the battery and black wire and between the black wire and alternator?? Just trying to figure the best way to bypass the bulkhead and make it good and keep it simple too.

[Pete in NH]

Now that you know the alternator is okay the question becomes is it connected to the battery. When you re-install the alternator start the car and put your voltmeter across the battery. You should see something around 13.8 to 14.5 volts.  If you don't there is an open path in the wiring. You can do as you suggested and run a wire directly from the alternator output to the battery through an 80 amp fuse which I think is the largest Maxi-Fuse available. I would then run a new #8 red wire from the battery stud on the starter relay directly through the firewall to the black lead that originally went to the ammeter. This wire should have a 50 amp Maxi-Fuse in it. The fusible link that went from the battery stud on the starter relay to the bulk head connector should be removed. The black factory  wire that went to the output of the alternator to the bulk head connector should be cut off at the bulk head connector. This gets the bulk head connector out of the way completely.

[69wannabe]

This is what I was thinking too just wasn't exactly sure how to go about it. What size wire do I need to run from the battery to the alternator?? 8 gauge also??? I have ordered two maxi fuse holders and a three pack of 80 amp and 100 amp maxi fuses. I have got to find me some 8 gauge wire connectors and wire and I will be able to go from there. Would the 100 amp fuses be too much between the battery and alternator or should the 80 amp be fine? Been planning on doing this for awhile but just haven't got to it yet!

[Pete in NH]

I would go with the 80 amp fuse between the alternator and battery. You can use #8 wire or #6 would be even better. I would stay with a 50 amp fuse for the second fuse for the rest of the car.

[69wannabe]

I haven't had any luck finding #8 wire at the parts store's but I went to home depot and they had #8 wire. It seems kinda like industrial wire so is it what I am looking for? I bought 15 feet of it so that should cover my needs. It seems just a touch bigger than the #10 that I have in my tool box. I ordered my fuses and holders from amazon which haven't arrived yet so maybe by next week I can knock this little project out and see how my charging system works after bypassing the bulkhead connector. Thank you for all the info Pete!!! I know when I have electrical issues you da man to talk to!!!!!!

[Pete in NH]

Most auto parts places seem to stop at #10 wire.  You'll find #8 automotive wire listed by various Ebay sellers. That Home Depot wire will be a little stiff compared to real automotive wire, it might eventually develop cracks in it from vibration.

[69wannabe]

I got me some #8 wire ordered from amazon. Yeah the home depot wire will work but it is stiff. Had to order me some wire connectors from amazon too. maybe all this stuff will arrive next week and I can get in there and get it wired up. It really will not take long to do but I got to get the stuff to do it with!!!

[69wannabe]

Actually picked up some 8 gauge wire from the local O'reillys. Got 12 feet of red and 12 feet of black. Picked up the maxi fuse holders from another local parts stores and ordered some ring terminals and maxi fuses from amazon. O'reillys actually had the 80 amp maxi fuses and they even had some 100 amp maxi fuses. I was surprised at how much of this size stuff I needed O'reillys actually had most of it in stock. I pulled my cluster and I have got my battery feed wire ran in from the starter relay through the firewall into the dash and tied into the original black wire. Had a small hole to the side of the starter relay that was open so I drilled it out to 1/2 inch and put me a grommet in there and ran the wire through it. Looks nice and clean and now I got to run my battery to alternator wire but it just turned really cold here and it calling for really bad weather for the next few days so it can wait til it get a little warmer for that. If I didn't have so much to do after work this week I could have had it done already but was busy every day after work this week working on other vehicles for friends and family. I have already got the maxi fuse holder wired in and got the ring terminal on for where it bolts to the battery terminal. Got the fuse holder wired from the battery so I can tuck it down beside the master cylinder so it will not be so noticeable, just got to tie to that and go straight to the alternator from there. Then got to put the cluster back in and see how it goes from there!!

[69wannabe]

Well it's been a week or so since I worked on finishing my bypassing of the bulkhead with my charging system wiring but I got it done today finally!! I had all the wiring done for the power feed into the dash and from the battery to the alternator. I had to heatshrink the eyelet at the alternator and add a dash light bulb for the cluster that for some unknown reason was missing and got the cluster back in (what a pain in the a$$) and checked all my lights to make sure all the bulbs were working and blinking like they are supposed to and started it up. It was not happy for a few min's since it's been several weeks since it's been started up but it warmed up after a few min's and was loping along nicely. I checked my voltage at the battery and it was 14.68 and at the back of the alternator it was 14.69. Much better than my last reading when the power was going through the bulkhead. And at the starter relay it is reading 14.58 which should be fine being that is not much of a drop at all. One thing I noticed is now when I turn the headlights on the volt gauge does not drop like it used to, it stay's steady. Before if I hit the brake pedal or turned on the headlights the volt gauge would drop quite a bit but it was still staying above the discharging range but it wasn't doing what it was supposed to and now I think it is working alot better!!

[Pete in NH]

Hi,

Congratulations on getting the charging system squared away. Your system voltages look right on target. You should be all set now. What you are seeing is a good example of how old corroded bulk head connector pins can cause problem.

[69wannabe]

That's exactly right Pete, That bulkhead is for sure a problem area and bypassing it the way you recommended is a good and safe fix and I recommend it highly for your charger or mopar in general. I feel like I got a good solid charging system now and I got some confidence back with my electrical system. Thank's Pete for the advise!!!

[Dino]

Pete's the man!   

He was a tremendous help when I did the same to my car, and then some.   

No doubt the best mod to do is to upgrade the charging system.  I was stoked the first time I took it out and could run all the electrical at idle at once without any issues.  I was smiling the first time out in the rain with it and the wipers would be steady at any rpm.   

[69wannabe]

Pete's the man!   

He was a tremendous help when I did the same to my car, and then some.   

No doubt the best mod to do is to upgrade the charging system.  I was stoked the first time I took it out and could run all the electrical at idle at once without any issues.  I was smiling the first time out in the rain with it and the wipers would be steady at any rpm.   

For sure Dino!! It has been so crappy here weather wise I am just waiting for a few dry days so I can drive it out and see how it does now. It was pretty pitiful before if I had the brake pedal mashed or even just running the parking lights. I'm already smiling so I will probably be cheesing once I hit the road with it!!!!!