Battery empty after 2 days, car won't start...

mrtask

mrtask

Well-Known Member
Hello chaps. I'm posting this question on behalf of a friend here in Berlin who owns a 2200TC.
P6-2200TC-1972-Tobacco.jpg

He wrote me an email asking for help, but alas I don't know anything about auto electrics, and can barely change a lightbulb myself!
He describes the problem thus: battery is always empty after just a couple of days. He has another battery, so keeps one always on charge and is constantly having to swap them over. He says as long as the car is 'warmed up' there is no problem, but cold starts mean he has to install a freshly topped-up battery. He reckons it is a problem with the alternator...?
What to do? What to test for, where and how? Hope somebody can give us a few pointers... :? :roll:
 
With the engine running and all accessories off, measure the voltage across the battery. It should be in the region of 13V or more. Now turn on the headlights and increase engine revs to 2000rpm or so and hold. Measure the voltage across the battery. It should be more than 13V. If it isn't then as you suspected Alastair, the alternator isn't charging as it should and will need to be looked at by an auto electrician. He or she can also perform this very test, so it might be best for your friend to take his car straight to one, let them test it and then go from there.

Ron.
 
Thanks for the helpful advice Ron and Geoff. Rolf, owner of the 2200TC in question, has emailed me some further info. He tells me the car (Chassis Number 4490XXXX C - Motor Number 450XXXXX A - Belgian export model) "should be positive polarity according to the manual. But, the battery is in the car the other way around, i.e: negative earth. Everything else electric works, indicators etc." Rolf wonders if he should put the battery in the other way round. I assume not, but assumption being the mother of all cock-ups I think asking all on here is more sensible! Is the car actually negative earth? (I have to admit I don't really understand what that means :roll: :| :shock:)
 
All 2200's are negative earth, as are most cars with alternators.
The most common cause for this fault is the bootlight staying on.
 
Thanks Harvey. If the battery is installed the wrong way round, would the car's electrical systems still work? I know this is probably a really silly question, sorry. Or does damage occur to anything in the electrical system? If so, what? Would the car still start and drive? Does it blow fuses, burn bulbs, catch fire? :oops:
 
mrtask wrote,...
If the battery is installed the wrong way round, would the car's electrical systems still work? I know this is probably a really silly question, sorry. Or does damage occur to anything in the electrical system? If so, what? Would the car still start and drive? Does it blow fuses, burn bulbs, catch fire?
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The fuses and bulbs will be fine and in theory the diodes within the alternator should be too, but I wouldn't like to guarantee that the voltage regulator will see things in the same light.

When you connect a battery across an electrical motor, it will spin in a given direction. If you reverse the polarity, it will spin in the opposite direction, not good if it is connected to an engine.

Ron.
 
I think I'd better highlight the seconf line of Harvey's post before the tekkie debate reaches white heat!

The most common cause for this fault is the bootlight staying on.
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Simply pull the wire off the connector on the bottom of the push switch at the front left hand corner of the boot aperture and try it for a few days. Or if preferred, you could try the well known small boy in boot trick. Place boy in boot and shut lid. When your conscience demands, disturb the resulting peace and quiet by opening lid and releasing boy. Besides you discovering how street his vocabulary has progressed to, he should also be able to tell you whether the light went out! :D

Chris
 
SydneyRoverP6B said:
The fuses and bulbs will be fine and in theory the diodes within the alternator should be too, but I wouldn't like to guarantee that the voltage regulator will see things in the same light.
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I doubt the diodes would be fine if the battery was fitted the wrong way! Even if they were, you'd be effectively shorting the battery out through the alternator.


When you connect a battery across an electrical motor, it will spin in a given direction. If you reverse the polarity, it will spin in the opposite direction, not good if it is connected to an engine.

Ron.
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Only if it's got permanent magnets instead of field windings.
 
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