 Battery Dead, While Disconnected??? |
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| PDXBob |
 Oct 30 2026, 04:25 PM
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#1
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Member  Group: Members Posts: 67 Joined: 16-May 20 From: Portland Oregon Member No.: 24,272 Region Association: Pacific Northwest 
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I have a 1975 914. Electrically it’s pretty sorted out. No bad wires, fuses all good, no major add-ons like amps, other items. No parasitic draws. However twice now when I’ve disconnected battery to do electrical work, when I reconnect the negative battery cable I’ve had a dead battery. Both times disconnected for about one week.
When I then put on battery trickle charger for a while it charges up, then runs fine(starts every time, doesn’t go dead). First time I’ve ever had a battery go dead when negative cable is disconnected. Bad battery or ??? Your thoughts appreciated! PDXBob |
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| fixer34 |
Oct 30 2026, 04:54 PM
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#2
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Senior Member Group: Members Posts: 1,481 Joined: 16-September 14 From: Chicago area Member No.: 17,908 Region Association: Upper MidWest
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I would put it on the charger for a couple days then take it to your FLAPS and have them run a load test.
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| Superhawk996 |
Oct 30 2026, 05:14 PM
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#3
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914 Guru Group: Members Posts: 8,155 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch
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QUOTE(fixer34 @ Oct 30 2026, 06:54 PM)  I would put it on the charger for a couple days then take it to your FLAPS and have them run a load test. (IMG:style_emoticons/default/agree.gif) I’ll go further; battery is scrap. Not uncommon for a battery have an internal short and to be able to take a surface charge and even be able to do a start. But when left over a period of time the internal short drains the battery. Just had this happen with a small 12v battery of the type used for emergency lighting, etc. Has happened to me countless times over my lifetime with car batteries. |
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| bkrantz |
Oct 30 2026, 05:54 PM
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#4
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914 Guru Group: Members Posts: 8,814 Joined: 3-August 19 From: SW Colorado Member No.: 23,343 Region Association: Rocky Mountains
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QUOTE(Superhawk996 @ Oct 30 2026, 05:14 PM) QUOTE(fixer34 @ Oct 30 2026, 06:54 PM) I would put it on the charger for a couple days then take it to your FLAPS and have them run a load test. (IMG:style_emoticons/default/agree.gif) I’ll go further; battery is scrap. Not uncommon for a battery have an internal short and to be able to take a surface charge and even be able to do a start. But when left over a period of time the internal short drains the battery. Just had this happen with a small 12v battery of the type used for emergency lighting, etc. Has happened to me countless times over my lifetime with car batteries. Yup |
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Posts in this topic
PDXBob Battery Dead Oct 30 2026, 04:25 PM
PDXBob
[quote name='Superhawk996' post='3276954' date='O... Oct 30 2026, 06:07 PM
dtmehall :agree: with Superhawk996 Oct 30 2026, 05:30 PM Root_Werks Shoot, nice it went caput in the garage rather tha... Oct 30 2026, 06:30 PM |
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