clawlan

Hi all. I am having an issue with battery current drain. On my second battery (Optima Red).

Now here is a big piece of the puzzle. When I was replacing the battery, I accidentally touched the battery connectors to the opposite terminals. Don't ask me how I managed to do that, but i got a nice big arc. After connecting correctly, car starts and runs fine except, voltage is 18v+. I know I'm lucky i didn't fry the computer or any host of other things. But it does seem I fried the voltage regulator.

Now this was all yesterday. I wake up this morning and the battery is essentially dead. Measuring < 4v between the terminals. I then checked the Key-off drain by disconnecting the neg battery terminal and connecting my DMM between the disconnected wire and battery terminal. Even at the 200m amp setting on the DMM, its off the charts. So I certainly have some parasitic battery drain.

I then disconnected the voltage regulator plug and re-tested the key-off drain. Now am reading about 135 milliamps. Does this seem normal? If so, it appears I just have an issue with the voltage regulator.

My concern is that it might not be the regulator itself, but just the regulator's ground, which I have no idea where it goes. I just don't want to pull the alternator, replace the voltage regulator, re-install and realize its the ground. Any help, advice, ideas?

mjr46

take all connections off alt and retest and make sure underhood lamp is unplugged......25-50 milliamp is safe drain at rest

MustangBradley

I made the same mistake on my 1989 lx5.0. When I did that, the amp light on the dash stayed lit. When I took it in, the mechanic replaced a fusable link in the alternator circuit. Problem solved. I don't know if this is what you need but it gives you another place to look.

clawlan

I'm not really that electrical saavy. Can you explain what this is and where it is so I know what to look for? Are we talking about a fuse somewhere?

My car will start and run fine, but the amp gauge shoots off the charts. Battery/Charge system test from advance auto parts tested it at putting out almost 18 volts. All the while the battery idiot light was on of course. Did you car have the same symptoms?

clawlan

I disconnected 2 wire harnesses on the alternator (is that all the connections?). Also unplugged the underhood lamp. Reading about 130 milliamps, the same as before.

Also, disconnected the battery wires and tested continuity between them. About 25 ohms. Not sure if that is good or bad.

mjr46

do what I said!!! a blown fusible like does not create a current drain it creates an open = current does not flow then = car may not start if certain links blow

clawlan

Read above...

mjr46

ohms means nothing in this case, you are looking for a circuit that is live when it should be at rest......the alt sounds like it is bad for sure, however it sounds like there also is another circuit causing a smaller drain too. pull fuses one at a time in the fuse box until drain is gone, then you'll have the circuit where the drain exists, from there grab a diagram of that circuit and unplug components on said circuit one by one until drain is gone, fuse must be reinstalled for testing

clawlan

Thanks for the tips. There is another dimension to this story that I haven't even mentioned. The reason I replaced my battery in the first place was that I was concerned there was a drain happening elsewhere. Why? Here is the abreviated story:

I had a Viper alarm system installed years ago. All was fine except several month ago, I would turn the key, the starter would engage, and then wouldn't disengage, even when removing the key from the ignition. When this happened, I was all alone without tools so all I could think of was put it in gear, and lay on the brake until the battery died. This of course burned up the main ground wire. After some troubleshooting and replacing the wire, starter, starter solenoid, and relay it still was not fixed. I took it into the shop and their electrical guy determined it was the alarm system. So they ripped it out (quite messily I might add), and the car then started and ran fine except the map light, power lumbar support, and power locks no longer worked (and yes, I checked the fuses under the dash). I tried taking it back to the shop and they gave me some BS saying they were not related and must not have worked before. In hindsight, I should have fought them but its a little late now. Anyways, the battery would still go dead, even after i had charged it several times.

Flash forward to this week. I decided to take the battery to be tested with the hopes that I didnt having an electrical drain, that it was just this poor old abused battery. They tested the battery and said it was bad and gave me a nice new replacement optima. In connecting the new battery, I reversed the terminals as stated in my original post and here we are.

Seems I have 2 issues. Dead voltage regulator and/or alternator which I caused by the battery terminal move, and an issue of something draining the battery from the alarm system/starter fiasco.

So it seems I need to take your advice and start pulling fuses one at a time and checking the current draw until it drops to the expected 25-50 ma. Ugh, what a nightmare this has been.

mjr46

for the 3 items that don't work, i'd look unde the dasd where alarm was installed and see if any wires were left undone if none spotted , you'll have to trace each circuit and see if any of the three take power or ground from the same source