Hi
I have a Sigma 2.6l auto which has a persistent problem with flat batteries. Whenever it is left for more than a couple of days it is impossible to start - dash lights dim, no starter power (even difficult to jump start). I have had replaced the battery (many times), had the alternator checked, replaced the starter motor - no solution.
Current draw sitting in the driveway - about 50ma (clock). Yet two days later flat battery.
Any help would be appreciated
Cheers Phil
I have a 1990 Laser turbo doing the same thing, and I'm just as clueless as you, having tried the same remedies.
I'm going to have to check the number of decimal places on my multimeter, when I get to my shop this morning ~ From memory, it seems like 5ma is closer to what a clock might draw.
In any case, have you tried disconnecting a battery cable for the 2-3 days it takes to kill the battery? It won't fix anything, but will show you for sure that it's a slow drain, if the car starts easily (don't forget to reconnect the cable ).
A Mercedes I was working on was driving me nuts with this problem ~ tiny draw for computer memory, but battery dead overnight. I got lucky one morning when the whole car was snow covered, except the side mirrors ~ they were themostatically controlled, switched on below 0° C, but should have been wired through the ignition; they were wired direct to the battery by a body shop doing accident repairs. The temp in my shop was too high, I missed it every time. Try leaving your meter hooked up longer, and sneak out to check the reading when the car is asleep...
I'll provide more useful info in 2-3 days, after you determine for sure that it's a draw, by disconnecting the battery.
DC3
Oops ~ my multimeter on 10A scale has two decimal places after zero ~ I was off by 10x, you were right. Clocks and computer memories seem to average about
30-60ma, and your car is reading in that range.I'll wait for your 2-3 day test with battery disconnected.
DC3
Althought I have a 95 galant, I have this problem.
What I have found so far is the like now is cold I put the heater in the rear on and I forget to turn it off and the system just drains the battery while driving. So it does not have a good charge and then after a day or 2 of sitting battery is bad. So far the alternator have been found to be weak and it will be replaced soon, also 1 cell in the battery was found bad, so the battery power is reduced.
Check the battery and the alternator, then put an ohm or voltage meter between the pos and the pos of the battery and monitor the voltage and ohm pasing by this cable. You might have a week charging system. Also as the car ages the wires increase resistance, so after a while it takes more power to reach the old parts.
Otto Ram> I have a 1990 Laser turbo doing the same thing, and I'm just as clueless as
Whoa, slow down here. You don't ever put an ohm meter on a power source, and a voltmeter can't measure ohms. Copper does not lose conductivity with age.
What you want to do is to use a voltmeter to measure the voltage AT the battery. The voltage as the car is running, should be about 14.4 volts. This will charge the battery. When you turn the car off, the voltage should drop to about 12.5 volts. If you measure less than 11 volts at the battery, with the car running, you have most likely a bad battery. If the battery voltage drops to 10 volts or less with the car off, try charging the battery with an external battery charger. If the voltage still doesn't come up replace the battery. I know, you said your battery is bad.
You can measure the current going into the battery, and coming out of it with an AMMETER. With the car switched off and the key out of the ignition, and the lights off (close the door), you should measure less than 200 milliamps being drawn from the battery. With the headlights and other items ON you can expect to see significant current draw from the battery (10 amps or better).
The 200 mA will eventual drain your battery, but it will take over a month with a good battery. The 200 mA is the backup power for the ECU , alarm if equipped, and the clock.
The voltage regulator in the alternator monitors the voltage of the battery. As the battery reaches full charge the regulator decreases the alternators output, so as to not over charge the battery, and boil it dry.
If you have a dead cell, the battery will never reach full charge, the voltage regulator will never see 14.4 volts and the alternator will always be putting out full voltage at max current, which if it continues to long will damage the alternator.
If you want to monitor the current in and out of the battery, you will need an ammeter capable of plus or minus 60 amps (use an automotive type meter, with a center scale of "zero"), and don't even think of putting it in series with the starter motor feed. The ammeter goes in series between the battery and the rest of the cars electrical wiring, but NOT the starter motor. The starter motor will draw hundreds of amps, and fry the meter. When the ammeter reads on the positive side, you are charging the battery, when it reads on the negative side, your discharging it.
I've always been pissed that they replaced the ammeter in older cars with voltmeters in newer cars, then dropped the voltmeter. I like to monitor my vehicle as I drive it. I know immediately when the battery fails because the ammeter indicates max charging for more than a few minutes after I start the car. The oil gauge indicated engine wear, and oil loss.
These instructions are basic, voltages are ball park, and if you don't understand the instructions, take the car to someone who does.
[snip]
Wanna sell it? I could use the parts for my 1990 Jeep Eagle Talon TSi AWD. I like my little car a lot, but repairs are getting expensive due to parts costs.
Regards, Mark "If a sports car can survive me, it must be GOOD!" Gibson
Wrongo! Copper wire does suffer from corrosion and that can reduce it's conductivity at junction points. It is not common, but it can happen.
I concur.
What is really a good bargain is to purchase a high quality multi-meter, a gizmo that measures voltage, watts, amps, and maybe some other things if you want a fancy one. (Yes, I do know that volts and amps will give you watts, but I am lazy.)
Cool story, I took my 1984 RX-7 GSL-SE into the shop to have a new battery installed, as it didn't seem to want to start a lot of the time. The mechanic examined the battery and said it just needed water. I thought it was a maintenance-free battery. He proved me wrong. Live and learn! He was way cool...I think he charged me about $5.00 for fixing things.
I am really glad you added that disclaimer. I'm more of a driver than a mechanic, but I know more than a few people who took advice from so-called "expert mechanics" who had no clue. I'd much rather have someone tell me "I can't fix it, but I'll tow your car to a place that can do it right."
Regards, Mark "When can I get a car that will hit Mach 2?!?" Gibson
I beg to differ, but we are splitting hairs here. Copper does not lose conductivity with age. The point of contact at junction points, increases resistance because a different material, copper oxide, has inserted itself between the two medals.
alternators
Some "maintenance free batteries" will let you pri off the caps that cover the cells. Others have them clued on so that you cann't get them off, or open them (well maybe with a drill). Car battery technology hasn't changed much in the last 50 years. It's still basically, Pb, H2O, and H2SO4 (Lead, water, and sulphric acid). You can still boil a maintenance free battery dry (and save it, if you can add water before it dies)
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