My battery (which is probably the problem) dies on me within half a day. This is a special dry-cell, light weight (blah, blah) battery that may be hard to find. It served me for at least 3years now and it is probably time to replace it.

My question is does anybody know what is a typical current draw on a late 944 with ignition key off and out? (mine measured at 0.09A or 90mA). I am interested to know if it is JUST the battery or there is some other problem. To compare a 2001 subary impreza measures only 0.02A or 20mA of current with the ignition off.

Thanks in advance.

 

I measured my '89 S2 recently, and got 60mA.

When I first started to measure it, I noticed the current was spiking every 2-3 seconds up to 600mA, and then dropping back to 60mA. What was going on?

It turned out to be the Blaupunkt radio (my model: Heidelberg CD50). It had a TIMS system (traffic information monitoring system) that was polling for updates every couple of seconds, even while the car was switched off. The system doesn't even work in my city, but the factory default for this model is "on". So that was significantly increasing the current draw.

Switched that off and the current settled down to a steady 60mA. So check out those radios, alarm systems , whatever...

-Mark

 

that sounds about right

 

The stock radio in my 87 na was killing the battery every day. I removed the radio and have had no more problems. I have not put a new radio in yet.

 

Thanks. It's not the radio - I pulled all fuzes and relays one by one while looking at the meter. The only one that made the difference was the interior lights fuze - draw went down by about 0.01A. I checked all the lights and didn't find anything shorted.
The draw I have must be caused by an electrical system that is not on the fuze in the hood fuze box. I am suspecting alternator winding doesn't have enough resistance and draws a little too much current... (Unless of course it is not connected when the ignition is off).

Any other ideas of where I could be lossing 0.04A? (Well at least I am at the correct magnitude of draw)

Thanks again for all your help...

 

The draw on ANY car should be less than 100ma (.10 amps), and the typically
less than 50ma.

Useable battery life without driving or without a trickle charger can be ROUGHLY
determined as follows:

Assume fully charged 60 amp-hr battery and 100ma draw,
and 50% of full capacity remaining for good cranking:

Time = 60 divided by 2 divided by 100ma = 300 hours = 13 days or 2 weeks

 

what is.... your favorite color?

Sorry, the title just screamed Monty Python to me.

Clean off your battery cables, terminals, grounds and have the battery load tested. If it's marginal it will evertually claim the life of your alternator. Thanks for the Formula Loren- that'll come in handy!

 

Chris, I apologize but I am way after Monty in addition to being from a different country.
Everything in the car is clean - top shape. Battery is just old. Thanks.

 

Grounding has been the source of about 90% of the hard to find auto electrical problems that I have had. You can verify that it isn't the grounds by using a jumper cable from the battery ground post to your starter attachment bolt. If it goes from a no-start to a start, it would that could be part of your problem. Of course if it still is a no-start you haven't proven anything.
--Roy--

 

Roy, I have checked grounds and added several of my own ground wires when I restored the car. Thanks for suggestion, though.

 

Check your door light switches. Make sure the interior lights go on and off as you get in and out. What happens is the switches get stuck in the "door closed" position. In our cars, if you stop and shut off the car and take the key out, the power windows still work until you open the door, then they are deactivated. If the switch does not cycle when you open the door and get out, the power windows still have juice going to them and the circut is live. This will be enough to kill your battery overnight. If this is the problem a good lube of the switch should fix it. Since you mention a drop in the draw when you pull this fuse, I'm betting this is it.

 

You beat me to it Dan, yeah, I'd be looking at the door switches.

 

Some good advice. Thanks. I think I am in trouble here as well - I rewired the power windows during interior restoration. PO cut all the wires going the PW system and wired them directly from the battery. I had to find switched and fuse-protected power under the dash to make them work properly. I used factory manuals to figure it out and forgot now where I ended up drawing power from. In any case, windows are now on a fuze and as I mentioned before, I pulled all fuses and relays in the hood fuse box. It's gotta be something that is not controlled by the box. Thinking outloud PO might have done some other stupid "modification" that I didn't catch.

Thanks again for all your help.