jwt996

I have an 88 Targa w/ 58k miles. Fresh new battery installed in the last 6 months, alternator checks out as good, yet the battery is discharged once again even though I was driving the car a few times a month for at least one hour each of highway 60mph trips plus the normal around town short trips.
I have double checked that the lights are not left on, radio is not on....so what is causing the battery drainage?
Your thoughts are appreciated.

Dan Cobb

I've been through this myself.

bought car, nearly stock except for aftermarket alarm.
rebuilt alt immediately after purchasing the car.
All seemed fine but the battery would die after just 3-4 days of just sitting, or a combination of just sitting and never getting to temp while driving short distances.
I replaced the battery w/ optima red top and the problem went away.
For awhile.
- I had the alarm serviced by the manufacturers' shop (they are here in Culver City, CA).
- I replaced the bulbs and cleaned/tightened connections and such for interior lights, under hood lights, etc. etc. made sure all were connected properly and operational, not somehow shorted out.
- disconnected ALL non original fuses for car alarm, stereo, etc.
- disconnected OEM clock.
Still dead in 4 days.

Removed alarm, took out all interior bulbs, etc.
Dead in 4 days again.

I finally tested the battery because it simply wouldn't hold a charge.
The optima was dead after just 3 years of light service.

I wouldn't have guessed that would happen, but it did.

I repalced the battery, but not the cables.

Start by hoping it's an easy fix.
Start eliminating the easy stuff.
Disconnect non-essential circuits while the car sits if possible and take voltage measurements on the battery daily.
If you notice a drop, you missed the load that is drawing current.
Pull out a fuse and 'bridge the gap' with a test lamp.
If it lights up, you have found a current draw.

I'm beginning to suspect the rear window defroster is capable of creating an unseen current draw, but I have not looked into that possibility yet.
Make sure your switch is off (and the glass isn't warm).

I did have the rear window out around the same time I put the Optima in, so perhaps it was improperly connected. I'm not sure if it worked before or not, as I have never had to use it.
It's on my list.

BTW, you can make a test lamp pretty easily by soldering wires onto a turn signal bulb.

If you do find a problem, you'll be happier if you have a copy of the Bentley wiring diagrams for your year. Without it, you will get lost in a maze of brown wires.

Good luck.
+++

Antony.

Hook up an ammeter in series with your battery, with everything off you should show that you have something pulling current that isn't expected. Pull and replace fuses until you find the offending circuit and work from there. You could also have bad connections at the battery terminals or to ground which is impacting the charging path.

84_Carrera

Remember the clock is connected too.

I know my radio is always-on to some degree, as I can eject & load CDs with the car off.

If I'm not going to be driving my car a few times a week, I usually have a trickle charger on it.

But yeah, the other guys are onto great starting points.

J. Brinkley

electric windows stay hot after you take the key out, and until you open the door. If the door switch is sticky your windows will stay hot all the time.

check by rolling the window down while in the car with it running. Turn the car off and get out and close the door. reach in and hit the window switch to roll the window up. If it rolls up the switch is bad and staying hot when you walk away from the car.

jwt996

Thanks for all of the suggestions. I had a new battery installed by AAA and the problem has occurred since then, so I am thinking that there might be a battery cable connection issue. I will let you know the result when solved.

dshepp806

battery connections, for sure. If this is turns out OK...then,...


,...moreso (as suggested earlier) check the drain current on the battery,...may have a bad switch somewhere pulling juice (and many other culprits).....either someone's draining her or your alt/reg is not up to snuff (albeit, for now, remote). Have you voltage measurements to share, as to battery measurements, etc.?

Quantify the current drain at the battery,..period. Something may be sucking,..and heavily.

Best,

Doyle