Saab won't stay charged

saab
batteries
900

#1

1995 Saab 900 Turbo. Bought new. Lifetime history of complete battery discharge if not driven at least every 2 weeks. New alternator, multiple batteries of no benefit. Have left on flowmeter for up to 1 week at dealer service center without unusual demand on battery. Any ideas.

Randy Forehand


#2

When it was hooked to the flowmeter what was the result? Now here is one for you…SOMETIMES…when starter motors begin to wear out…the starter will drain the battery…HOWEVER NOT ALL THE TIME…the reason for this is that the starter will only drain the battery at a very specific spot on the starter motors stator rotation. Meaning the starter motor itself has 360 degrees of rotation…now the drain may only set itself up at lets say…10 degrees…45 degrees…120 degrees…or what have you… Any other stator location will not drain the battery…but when you hit those magical degrees of stator rotation…it drains the battery.

The reason behind this is due to the enamel coating on the windings of the motors STATOR....when it stops at one of those bad spots, the winding wires enamel coating is worn thru SOMEWHERE in all those hundreds of windings and grounds out...there goes your batt power.  You could never see it or know where the bad spots are unless you actually saw burned wire on the stator....and you would have to have the stator in your lap and even still may not be able to see it at all.....I am telling you that this is VERY REAL  It just happens to starter motors stators....Usually caused by weak battery making the starter motor struggle while engaged with the flywheel or by engaging the starter for too long a period of time thus overheating the stator and windings....this builds up a ton of heat and can damage that enamel coating in places.  Strange AND true.

These failures can drive you completely NUTZ to try and diagnose if you have never seen this before…TRUST ME. This is a very real world failure of the starter motor that I am describing… These failures DO occur and I have diagnosed many of them in my time… Now I am not saying that this is definitely YOUR issue, but rather describing the possibility of this very confusing failure mode…It wouldnt be very expensive to install a new starter if you did it yourself to see what happens. I am betting on the starter as the culprit…when it stops itself at those random locations on its 360 degree rotation…Crazy I know, but trust me a starter CAN do this and it will seem totally at random, because it IS random…you never know where the stator will stop after spinning your engine over.

If you dont want to replace the starter you can after having the battery fully charged…remove the hot wire on the starter motor itself and see if the battery drain ceases… When you take that hot terminal off the starter you will need to tape up the end because it is “HOT” all the time. YOu will have to disconnect it after running the car each time and see how long the charge lasts in the car…if it changes drastically from what you are used to…you found a failing starter motor.