Battery draw, I have isolated the fuse but.....

[old man neri]

Background:

I was away from home for a month, come home and the battery is weak, not strong enough to start the car but it does turn it about half a crank. I jumped it and went on my way to work. End of the day from work get in car, turn key, starts wonderfully.

Next morning....nothing, not even enough to keep the clock going. A totally dead battery.


I suspected a draw and I found one. Fuse/Relay panel 1, fuse 1. Bentley says it's the Clock, glove box light, luggage light, and interior light. With all of these disconnected I still get 0.5 amps draw. With the fuse out I get no draw.

Help.

PS the clock seems to draw .2amps, is that normal? Or is that due to the fact I am running it with lower than normal voltage.

[gshase]

The clock might draw 30 ma not .5 amp. You still have something making heat, could be a stuck light burning (check at night with no other lights on) . I have seen a jamed CD player draw .5 amps and whipe out a battery. Check for a warm relay that is stuck on. Something is drawing that .5 amp and you have to find it.

[old man neri]

Alright, found the problem. Basically, I am an idiot.

1) I looked up the wrong page in Bentley, for my year it also lists the radio. The radio was drawing 0.5 amps. .1 when my ipod wasn't plugged in. I guess it charges it all the time.
2) The clock only draws 0.2 amps when it is plugged in backwards which is exactly what I did when I plugged it back in.

So I am guessing (hoping) that the reason it died overnight was that I left something on (headlights, turn signal...etc)


We shall see. Right now it only draws 0.12amps when all is plugged in (minus the dead ipod).

[gshase]

I think you still have an issue. How accurate is your meter? 120 ma will drain your battery over several days. Something is still creating a warm spot.

[old man neri]

It's only the radio that seems to draw it. My meter is about $30 accurate.

[RSTarga]

First recharge your battery correctly so you have full charge, the alternator will not completely recharge a dead battery unless you take a 12 hour drive.

[old man neri]

On a borrowed battery charger as we speak. The battery is disconnected as well.

[tcar]

What year?

Dome light and ???? (frequency valve maybe? if you have CIS - not sure) is on the same circuit.

[old man neri]

1988

[Wil Ferch]

Standby "spec" draw should be no more than 16 milli-amps.... 16 mA....... for the 3.2's

Pull the light bulb either in the glove box light or the trunk light....then check again.

[uwanna]

I had the very same dead battery problem as you, a couple of months ago. Drove me nuts, day after day a dead battery! I had somehow inadvertenty left the glovebox/map light three position switch in the "always on" position! Never noticed it because I only drove the car during the day. Walked out one night and saw a faint glow in my interior. Voila!, problem solved, and I felt like a real dumba**.

[86 911 Targa]

Originally Posted by old man neri

1988

According to the Bentley, 0 to 100ma is normal residual drain.

400+ ma would indicate a problem.

Assuming you have the "boat anchor" 80A battery,
in good condition, a drain of .5A would deplete the battery in about
160 hours.

100ma would drain your battery in 800 hours.

However, long before those numbers, your battery would not have the cranking
amps to start the car.

pm me as needed.

Good luck,

Gerry

[dad911]

How old is the battery, running it down might have killed it.

[morrisjm1]

Not sure if it applies to an '88, but here's what I've done...twice. On the '78 there is light under the dash above the glove box knob, the switch that is either, OFF, On, or Switched to operate with the door switches. I keep the garage door opener in the glove box I have accidentally moved the switch to On while opening/closing the glove box. In the day time, you don't notice the light is on and if you don't go into the garage when it's dark and see it glowing and turn off, it will kill your battery.

Mike