Tom W

I'm well on my way to killing my second Optima Red Top if I can't get help.

My car appears to have a mysterious battery drain. My batteriy is pretty much drained after about a week of no driving (which happens pretty often considering it's track only use). One battery died from frequent recharges and was replaced by an Otima Red Top (I now know that a Yellow Top would have been a better choice, but I digress). After draining the Red Top 5-6 times in about 6 weeks it got a bad cell and was replaced. After blowing the fuse in my digital multimeter a couple times, I finally realized I needed a new meter that would take more amps. I bought one today and continued down the trouble-shooting path outlined in Adrian's book.

I have about a 99 mA drain with everything off. I get a reduction of about 15-20 mA when the clock fuse if pulled. I pulled every fuse and most the relays and could not get the draw below 80 mA. I do not have an after-market alarm. The radio, amp, and speakers are gone and the green wire taped to prevent a short (and the radio fuse has been removed). I've removed the fuses for the non-existant power seats (replaced with Recaro's) and the fuse for the CCU (removed, needed the space for the fire suppression system controller).

I ran out of time tonight to do the last thing mentioned in Adrian's book (look for corrosion on the back of the main power distribution/fuse board). I'm not hopefull that this will be the cure. Anyone got any bright ideas? I missed most of my last track outing due to a failed CV and wheel bearing, I'll be really bummed if I miss track time this weekend at Laguna Seca due to battery issues.

Adrian

Dear Tom,
Lets try and look at this from a slightly different angle. Have you installed any systems which are not part of the standard electrical system, such as the Fire suppression system?
I had a similar frustration years ago and eventually found an inline fuse, hard wired to the battery (switched earth) for a mobile phone hand free system installed under the water soaked sound proofing on the passenger side front.
Is your internal lighting system still intact?
Ciao,
Adrian
964C4

mojorizing

Try pulling the fuses and relays in the engine compartment fuse/relay panel, and see what you get. At that point you'll have all fuses pulled?

Adrian has a good point......look for added wires to the battery directly, that's were cell phone, stereo, etc. installers get power.

Tom W

Adrian,

The fire suppression system is battery powered so it will still work in the event of power loss or power disconnect.

As I was getting up this morning I did begin to wonder about the possibility that it is associated with the electrical system disconnect that is wired into the car. The is a lot of spaghetti wiring for this switch. Since I didn't install it, I have no documentation of how it's supposed to be wired and removing it might be an issue. I did disconnect the battery and put it on my trickle charger that way to see if it "faults". With the disconnect switch connected the trickle charger has been trpping into fault mode - which I assumed was due to a bad battery. The first Optima was bad after about 2 months, but the new one tested good, but drained, yesterday.

Anyone ever had one of these go bad and have a "leak" that shorted the battery?

When I first got the trickle charger all worked well and the charger switched to maintain mode after a few hours. Now it never switches to maintain but to fault. I'm wondering if the charger didn't damage something in the cutoff switch ...

Oh, I'm not sure of an inline fuse/seperate circuit (other than the cut-off switch) because of all the wiring for the switch. I will take a closer look at it tonight.

darth

Did you pull the 3 fuses in the engine compartment? Mine is drawing 52.3ma and with the clock/radio (aftermarket) fuse pulled it drops about 10ma to 42ma and there are a couple of other fuses (i.e. I think DME is one) which drop it another 10ma altogether. Even with all the fuses and relays pulled it still draws about 30ma - where is this current going?

Bill
90C2

Tom W

Bill: No I didn't get to the engine compartment last night. Thanks for the reminder. I did pull the DME with change in current (the darn thing had no cover on it - the PO evidently puled the plastic off in trying to remove it and put it back in naked).

Kahdmus

Tom, I got a spare DME if you need it and your driving past (presume you use HWY 1/Devils Slide vs. 208/92) Im only 3 or 4 turns off the freeway!

Tom W

Howard, Thanks for the offer. I have/had a spare as the 993 and the 964 use the same part (and I've had a spare for the 993 for a couple of years as it's a part known to fail).

You should drive down to Laguna Seca Sunday or Monday and say hello to all us crazies at the track.

Tom W

I noticed I missed answering a question from Adrian - yes, my interior lighting system is intact. I think I have them both set to always off though as the roll cage really obstructs the lights and makes them useless.

Series 900

one of the draws could well be the interior lighting/ electric windows. There is a relay the stays energized after key off, yet releases upon door opening. Let me explain the process, drive car, roll down window, park car, turn key off, oops, window still down, instead of turning key back on, relay is energized allowing window operation, roll window up, open door, interior lights come on, activated by negative trigger of door switch on jamb, same negative trigger also deactivates window relay, thus windows will not work with key off, close door lights go off, relay has also been closed upon the first trigger. To check this, look for correct operation of interior lighting upon open/closing of the doors, BOTH sides! If one of the door switches has a dirty contact, never completes the ground circuit, the window relay will stay energized, and be the source of draw, and your windows will always work, till the battery drains!, which was not the design. A simple back/forth twisting of the black plastic plunger switch after removal of the rubber nipple on the a pillar door jamb will usually clean the contact to ground, or remove and clean, apply dieletric grease for piece of mind. push switch to test for correct operation of all functions, reexamine draw at battery to test if draw has been reduced. If the door switch/ relay was at fault, your dead battery days are now over.

PS Tom one of the reasons you may have missed this operation is you mention you have the lights off, not that this affects the window relay, but you may have missed the loss of ground completion at the door switch by not seeing them come on as you shut them off and considerd that "fact", they do not come on becuae you shut them off, verify they work still in door operation mode!

914und993

A 99 mA drain, while high for the car, shouldn't be too much for a good battery maintainer to keep up with. You might have better results with a different one, like a Deltran Battery Tender Plus.

Chip