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Discussion Starter #1
Hello,
Kind of a basic question… I feel pretty good about mechanical stuff but electrical and electronic stuff I find just plain mysterious…

So, 73 US spec GTV… :thumbup: My battery doesn't seem to hold a charge anymore.:scared: It's the same battery that was in the car when I bought it 4 years ago…seemed to look pretty new back then. I put about 4,500 miles on the car in mostly warm dry weather. I have run down the battery once by mistake by leaving the lights on.

Now I can charge it up but it loses any punch after a day and won't turn over the engine shortly there after.

Does anyone have a recommendation on diagnostics?
(I have a multimeter and I'm not total inept - just don't don't have any feel for stuff I can't touch, feel, throw or break:blink:)

Or, do I just need a new battery?

If it comes to a new battery, any thoughts? I'm not a purist…It's a nice driver but I'm OK with mild modifications for amusements sake.:cool2:
 

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Batteries don't seem to last as long as they used to. 4 years might just be the end of its useful life.

Before condemning the battery check for a parasitic drain. Modern radios use a few milliamps to maintain their internal battery & station pre-sets. But that level of drain should allow a fully charged battery to hold enough charge to start the engine for a week or three.

If you VOM ("multimeter") has a 10 amp setting, use that to test for a drain of the battery. Remove the negative cable from the battery, connect the VOM (set at 10 amps) between the disconnected cable and the battery's negative post. If you get any measurable reading with everything off (close the doors so that the courtesy lights are not on) then something is drawing too much and that is running down your battery.

To track down such a drain, pull one fuse at a time until the meter responds by going to zero. Now you know that the drain is something in the circuit controlled by that fuse. Happy hunting...
 

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Discussion Starter #3
the hunt

Eric,
Sounds simple and like enough of a lead to go hunting…. Hopefully my mechanical brain can cope…wires and connectors are mechanical…right?
Perfect, thanks.
Rich
 

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Just remember, electricity is conducted by smoke, not electron flow. When you find where the smoke comes out, you have found your drain...:thumbup:

Eric,
Sounds simple and like enough of a lead to go hunting…. Hopefully my mechanical brain can cope…wires and connectors are mechanical…right?
Perfect, thanks.
Rich
 

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And there is no such thing as an electrical failure - all failures are either mechanical or human. :)
 

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Discussion Starter #6
Escape from Turkey festivities

OK,
I managed to escape from Turkey :chef: festivities long enough to slap the "multimeter" on as instructed.

As ghnl instructed
Ohm meter set to 10amps
Zero "smoke" leaking out (Reads 0.00 - 0.01 Amps)
If I open the door, it reads 0.37 Amps and my courtesy light turns on.

The digital gage on the Ohm meeting kind of flip flops back and forth between 0.01 and 0.00 for a few seconds before settling down to 0.00 :innocent:

Is 0.01 nothing or do I need to trace to find this leak?

I'm thinking 0.00 to 0.01 is nothing and I need a new battery but any advise is welcome.

Happy recovery from Thanksgiving! :thumbup1:
 

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A typical new car battery can hold a charge of 40 amp hours. If your drain is .01 amps then the battery should discharge in 4000 hours which is about 6 months.
 

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Discussion Starter #8
Math Love

Well,
That makes a lot of sense. The existing battery is not lasting anywhere near 6000 hours so I think its time for a new one. Many thanks to AlfaBB and those who offered their feedback.

P.S.
Any opinions on 0.01 amps leaking…? Worth hunting or would I be chasing the inconsequential?
 

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That is 10 mA. What is the resolution and accuracy of your meter? 10 mA may be within the uncertainty of the reading. It is possible that your radio draws a few milliamps when it is switched off.
 

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Are you sure your alternator is working properly? If it's not charging your battery then it won't take long to drain the battery. The simple test is to start the car and then pull one of the leads off the battery. If it continues to run then your alternator is good. If not, you've got a problem with your charging system... Possibly in addition to a bad battery.
 

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4+ years is a pretty average life on a battery in a car that is only driven about 1,000 miles a year.

Another way to verify that the battery is failing to hold a charge is to charge it up and disconnect it from the car. Check the battery voltage 24 hours or so after you remove it from the charger. If it doesn't read at least 12.4 volts (~ 75 % charge) it is self discharging too quickly and is ready to be replaced. Fairly rapid self-discharge like this indicates that the battery is shorting internally and is done.

Good luck with it!

Bob Stewart
'73 GTV
 

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Discussion Starter #12
Seems to go faster too

Hello,

Snow finally melted and enough salt is washed away…

Replaced the battery and that seems to have done the trick. Really seems to help cold starts… Thank for the advice to my very basic challenge.

By the way, does a new battery effect the handling? :thumbup:

(Thanks)
 

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much faster. Wash it and change the oil and it'll be even faster!!! Read up on how a battery functions and you'll get it. 4 years on a car seldom driven? I'd be very happy. ciao chris
 

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We purchased our 1964 Porsche 356 SC in 2003, it had an Optima battery. It has worked fine for the last 11 years, but has been getting weak for the last year or two. This year it does not seem to be taking a charge so I am looking for a new one. It's a 6 volt and has served well for 11+ years. I call that value

Approx. 600-1000 miles/year
 
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