Battery Draining

**kenro23** · 08-04-2014, 06:35 AM

When I had my car in Hawaii, I replaced the alternator twice in a span of 5 years. Within those 5 years, if I didnt start my car at least two times a week, the battery would die. At the time I thought my battery was just old (same one as when I bought the car in '07) mixed with the after market stereo.

Within the last month I have replaced the battery only to have it drained after not starting it for a week. My Dad thought it was the alternator and tried the old trick of starting the car and taking the lead off the battery to see if the car still runs. When we did that the car died so he thinks its the alternator.

My Dad spoke with someone who rebuilds alternators and this guy tells him that the removing the leads trick doesnt work on newer cars as it did on older ones (obviously a '00 isnt new but you get the point).

What do yall think the problem is? Also, is there any truth to what this guy told my Dad?

Thanks in advance for your help!

***SMWS6TA*** · 08-04-2014, 06:49 AM

When it is running how many volts do you see on the dash? Should be charging around 14v. Around 12v it's not really charging the battery, barely if any.

Check the grounds at the battery and the negative post on the passenger fender. If they are corroded or not connected properly it will effect the charging of the battery.

With the alternator make sure the thin wire that connects to the alternator has a solid connection, that it's not loose in the plug. Is the alternator cover in ps fluid? I've killed several alt's because of the ps pump high pressure hose leaked on the alt.

Could the radio be drawing a charge even with it off?

**kenro23** · 08-04-2014, 06:53 AM

12v is usually what it is around.

I will check the ground, wire on alternator and if its covered in ps fluid tonight when I get home from work.

I am not sure about the radio drawing a charge when its off. I would assume not but im no electrician.

***SMWS6TA*** · 08-04-2014, 06:56 AM

electrical gremlins are the worst to troubleshoot.

**kenro23** · 08-04-2014, 07:00 AM

Especially when u dont really know what you are doing with it.
I did all that wire hiding stuff on that side of the car...I wonder if that has something to do with it??
Not sure if the problem was before or after that

***SMWS6TA*** · 08-04-2014, 08:17 AM

Where did you relocate the ground post wire?

I had to grind off some paint to ensure a solid ground for my relocation.

**kenro23** · 08-04-2014, 09:09 AM

Off the top of my head, I dont think I messed with it honestly.
With that said, would that ground be the only wire that wouldve been messed with?

**bigrondownhiller** · 08-13-2014, 03:51 PM

12v is not enough. Do some voltage checks at the back of the alternator and at the battery.

**pajeff02** · 08-14-2014, 11:51 AM

With the engine running, check your battery voltage with a DVOM - should be at least 13.3 to 14.4 if all is good.

Draw tests are easy - you just want to make sure it isn't pulling too much juice or you'll cook the fuse in your DVOM. With the engine and ignition off, disconnect the positive battery cable. Take a test light and connect the clip to your positive battery cable and touch the probe to the positive post on the battery. The intensity of the glow of the test light represents how much current is being pulled from the battery. If the light is really bright, do not use your DVOM. If the light is dim to medium, you should be ok to set your DVOM to test for milliamps (mA) and insert it in place of the test light - one probe on the battery and the other on the cable.

You can then measure your battery draw. Generally, anything over 30 mA or so is excessive and will run down a battery. Higher draws will run it down quicker. I was working on a local police car on Tuesday and had measured draw in excess of 200 mA, which is why the battery was always dead within a day or so unless hooked to a charger. With the DVOM in place, have a friend start pulling fuses one at a time to locate the source of the draw. Don't forget the fuse panel on the end of the dash and any fuses for aftermarket electrical accessories installed on the car. Certain things, such as the radio, will have a small amount of draw to maintain the time and station memory. You are looking for something that is drawing too much power, or that is drawing power when it shouldn't be. This will help you locate the offending circuit(s) and you can then work on determining if a component is bad, or what the issue is.