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Before I buy a new battery..

2K views 8 replies 7 participants last post by  delawarebill 
#1 ·
Got my Trabant put back together today. 3rd and 4th gear are now working fine but I ran into an electrical problem which could pertain to any car.

The car has a 6V charging system.

Just like my 68 Ford, 87 Yugo this car is hard to start in the summer because it's carburated. Maybe?

So I'm at my parents house and try to crank it over. Eventually the starter motor just quits spinning all of a sudden and I have no power. None at the headlights, horn, interior light. No battery light in the speedometer either.

I start checking connections and can't really find anything out of the ordinary.

My battery voltage is 6.21 volts. You would think this would be enough to at least cause the interior light to glow dim.

So I hook a battery charger to the battery set at 6 volts. Now I have power but still the starter refuses to spin over. So I tried another one.

What's weird is the needle on both battery chargers I have tried reads 0 amps as if the battery is fully charged. And I can't hear either of them "HUMMM".

So I tested the voltage directly from my Sears charger. It produces 8.3 volts. Yet when it's connected to the battery it reads the same as if it was not even connected (6.1 volts).

I've checked some of the connections. I have not ruled out the ignition switch but some circuits don't go through the ignition switch like the interior light.

Negative battery cables checks out OK as well as power at the starter.

I'm wondering if the battery has shorted out. It will be 3 years old sometime this year and just has a 12 month warranty on it.

Almost sounds to me like the battery has shorted out and is sucking the juice while trying to recharge the battery with a charger?
 
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#2 ·
Sounds like a bad battery. A plate must be broken (open circuit)
You will still read voltage across the terminals as the electrolyte will conduct power, but no real amperage will flow.
Batteries that do that can explode so be careful. Get a new one.
 
#3 ·
Got my Trabant put back together today. 6V Just like my 68 Ford, 87 Yugo this car is hard to start in the summer because it's carburated. Maybe? Eventually the starter motor just quits spinning all of a sudden and I have no power. None at the headlights, horn, interior light. No battery light

. Sounds like you've got a weak connection somewheres...


. Put meter on battery posts and hit the starter... if battery bad, meter will go to near -0- volts... if stays 6+ volts, problem elsewhere... trace out voltage on + side and then on - side of wiring to see where voltage disappears...


. A properly tuned carb. car will usually start faster than new EFI cars under all conditions because the EFI cars usually need to spin over a couple times before the ECM finds where all its parts are... shouldn't even hear the starter crank the engine over on a tuned carb. car, should start instantly...
 
#4 ·
You were correct!

It took buying a new battery (only to return it after the fact) to figure it out.



I replaced both battery cables (not real sure which one was at fault) and the problem is now solved. Even the engine seems like to turns over twice as fast and although too soon to tell, my engine speed doesn't drop when I turn on the headlamps like it was doing before.

Now here is the kicker. Although the cable connectors looks dodgy, both battery cables checked out perfectly fine with an ohmsmeter. No resistance, plenty of voltage at the stater. Yet it wasn't until I replaced both cables was the problem corrected.

Also my LED test light which pulls probably less than 1 amp was misleading. It would light up but nothing else would on the car.

So I guess sometimes you just have to replace a part to find out if it's good or not even if it checks out fine otherwise.

As far as "hot starts" in the summer time on carbed engines, maybe this car won't be as hard to start now that the stater is spinning twice as fast.
 
#6 ·
. The battery clamp you picture is not a stock auto factory unit... it's a universal replacement and a crappy design... just good enough to get you by until can get some good clamps/cables...


. As soon as you see rust on that universal clamp, you know what the problem likely is...!


. Modern electrical testers draw so little power, they can't discover a weak connection... the test procedure I outlined gets around that problem... switch on starter or headlights and then trace out voltages until you find where the voltage hasn't reached... if no tester, just wiggle wires until something makes sparks, headlights come on, or starter spins... just stay away from engine driven fans while checking...
.
 
#7 ·
When a battery goes bad, it often will give all good reading, except when under load. That's when they often break down, or short out. So you can put a meter on it, and have someone try to crank it, to see what it's doing; or you can take it to a chain parts store and have them check the battery.
 
#9 ·
cables

ya that old fitting is a junker like all have said.. when u get it started again run at say 1500 rpm's and ck the voltage at battery again.. the 6v sys should be just over 7v's. if 6.5v then bump the regulator up. i'm assuming u still are a generator ??? on the 6v sys u really need to make sure all the connections are good and clean.
 
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