Short? Battery drains over night.

Gotta love that wiring . . .
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Ian86s

Short? Battery drains over night.

Post by Ian86s »

If I don't disconnect my cars battery when I'm done driving it, it will be dead the next morning.

With the key off there is still a considerable drain on the system. i took out the battery and hooked my volt meeter up to the leads, it showed current running through the system, but not at full strength.

I don't know what to do. my project is coming along nicely but this just puts a bummer on it. the battery I have now is completely trashed from being discharged and recharged by the previous owner. (he didnt tell me it ate batterys. :evil:)
mdrburchette
Posts: 5754
Joined: Wed Jan 25, 2006 5:49 am
Your car is a: 1972 Fiat 124 Sport
Location: Winston-Salem, NC

Re: Short? Battery drains over night.

Post by mdrburchette »

You can isolate the problem by pulling one fuse at a time and checking for a draw.
1972 124 Spider (Don)
1971 124 Spider (Juan)
1986 Bertone X19 (Blue)
1978 124 Spider Lemons racer
1974 X19 SCCA racer (Paul)
2012 500 Prima Edizione #19 (Mini Rossa)
Ever changing count of parts cars....It's a disease!
So Cal Mark

Re: Short? Battery drains over night.

Post by So Cal Mark »

if you're using an voltmeter and not an ammeter, you'll need to put the voltmeter in series with the battery cable to check the draw. Remove the neg cable and put one lead from the voltmeter on the cable, the other on the battery post. That will show the draw. As Denise suggested, you can remove fuses one at a time to check for a draw, but most of those circuits don't have battery power, only ign power. Try disconnecting the alternator, bad diodes can cause a pretty big draw.
Ian86s

Re: Short? Battery drains over night.

Post by Ian86s »

Well while poking around, I found it! It seems the alternator is shorting out a bit? when i disconnect the two leads to its + post, (but left them together), there is no draw on the battery terminals, unless i turn on a switch.

Is this common? where do i get a replacement, or how do i repair the alternator?
So Cal Mark

Re: Short? Battery drains over night.

Post by So Cal Mark »

I'd find a local rebuilder that does custom rebuilding. It probably needs a diode trio, but other parts in it can fail too. I'd try to stay away from the rebuilt units the chain stores sell. They're usually just repaired (rather than rebuilt) and painted.
pope

Re: Short? Battery drains over night.

Post by pope »

Whew! I am glad you found it, now I dont have to use my suggestion of buying an extra battery and swapping it out every morning. LOL
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