Greetings fellow volvo owners,

my 1992 volvo 240 is draining batteries like crazy. I've bought two batteries because of this problem and it has recently gotten worse. it used to suck the life out of a batery slowly if left sitting for more than a week. now the problem is that it cant even start on its own, after being jumped and charged for 30 min. the battery dies after a minute or two. I've tried checking the codes, but there may be something wrong with the light/ button because it isnt flashing at all.

also, it has a new alternator, so i know thats not the problem.

thanks in advance for your help!

so I checked for a drain (touching one of the cables to one of the terminals) and there was a noticeable spark. I unplugged the trunk light and there was still a small spark, but it wasn't as distinct as the first one. also, could this be linked to my engine surging problem?

http://www.brickboard.com/RWD/volvo/1562667/220/240/260/280/engine_idle_surge_misfire_240_problems.html

Are the power door locks giving problems? If so, then there's a drain through shorting. Disconnect the connector with red/blk/grn wires that are by the driver's left knee. Does drain stop?
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1980 245 Canadian B21A with SU carb, M46 trans, 3:31 dif, in Brampton, Ont.

I had the same problem after my alternator was replaced. Turns out the wires on the alternators two tabs were reversed and allowed the battery to drain. I reversed them and solved the problem

bad voltage regulator, faulty wireing to alt or starter, faulty wireing on the drivers door lock [the part that wraps around the cylinder]. You will need a voltage meter to do some tests.

If you do not have a voltmeter with ampere capabilities you can use a small light bulb or test light connected between the negative cable and the battery. If it burns brightly you have a drain.

If the cars sits and the battery dies then something is on in the car. If you yank the fuses out of the fuse panel or others in random areas one at a time that should eliminate 80 percent of all possible draining circuits.

What can be left are the straight battery power supply circuits that are not fused, starting with the main cables. They go down to the starter and around to the alternator, which go under the engine inside a harness.

If you disconnect the two cables at the starters central binding post and the light goes out you will have your problem in one hand or the other.

Putting the battery positives side back onto the starter only and having the light stay off, tells you it is in the harness to the alternator. If it stays on the bad circuit is in the harness that the cable is in.

Disconnecting the alternator D+ will rule out a grounded alternator through its diodes and puts the offending circuit to ground inside the harness. It may touching the engine through a bare spot or through other wires that go to ground via components connected by the harness.

This is a fast and dirty troubleshooting method by the way!
No body likes the land down under the car. If you have good dexterity and limber arms you can do it from above.

Just keep the negative cable with the light bulb between the battery and the cable. This will act as a current limiter in case you touch the positive side to the cars body.

Good luck,

Phil

Have you actually tested this "new alternator" or just assuming it's good because it's new?

http://www.brickboard.com/FAQ/700-900/ElectricalStarting.htm
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Post Back. That's whats makes this forum work.

i assume its not the alternator because the engine continues to run without the battery. i could be wrong, but i'll give it a shot.

Wait! You just wrote, "...i assume its not the alternator because the engine continues to run without the battery...."

Did you mean that you pulled off a terminal and disconnected the battery while the engine is running?! That will kill the alternator instantly! Yes, it will drive the ignition coil to keep the engine running, but the voltage regulation is gone.

Unlike magneto-type small engines (e.g., lawnmowers, small motorcycles, etc.), an automobile (and boat engine) alternator MUST ALWAYS be connected to the battery -- oversimplifying the explanation but close enough in this case, the battery absorbs the output of the alternator and prevents huge voltage spikes that destroys the solid state components (diodes or rectifiers) in the alternator.

What you should have done to check for a battery drain the right way is to get a VOM meter (a few bucks in Radio Shack will suffice) and measure milliamps in the car's circuits. Start at the battery: 12 ma (0.012 a) with brief pulses to 25 ma for the clock motor is normal. Then test across the car's fuse panel (remove fuses and use the electrodes across the fuse connections), searching for the draining circuit to narrow down the possibilities.

I second Walt's suggestion to check the alternator. Anytime somebody writes, "it has a new ______, so i know thats not the problem" it is a red flag.

Otherwise, get an ammeter and check the drain on the battery.