Wierd battery behaviour

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Thu 5 Dec 2002 18:49
Wierd battery behaviour - dan
I recently flattened my battery after a trip to a bodyshop and after MOT'ing it etc... found the garage could not start it up again. They tried jump starting it using alternative batteries and a mains charged pack that showed a full charge. The engine would turn over better than normal but it simply refused to start. At one point they were considering looking at the fuel pump as it WAS sparking.

Only by getting a van in, revving the nuts off it whilst attempting to start my car with its battery would it do so. After a 2 hour drive ts the battery appears to have recovered, it cranks sluggishly but always starts after 2 audible turn-overs even though it sounds much less lively than when they attempted other sources that failed??

Is this a volts Vs amps thing?
Regardless its worth remembering not to give up on the battery as the source of the problem unless you've tried to start it with a starter pack directly linked to the mains...

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Thu 5 Dec 2002 20:53
Wierd battery behaviour - Peter D
If you go for a run for 15 minutes then come home and leave the car for 30 mins and then measure the battery voltage does it measure 12.6 volts or more ?? If it measures less then you have a shorted out cell. New battery required. Regards Peter
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Mon 9 Dec 2002 22:11
Wierd battery behaviour - GGM JULES
What car was it? If battery checks out ok ie 100% State of charge(12.7v = 100%, 11.6v =flat,) and all cells are fine (use hydrometer or drop-tester)then always prove earth lead by taking a single jump-lead and connect first to batt., then to 'orrible lump of metal on engine (by-passes earth lead to body and to engine, poss 3 points of poor connection)Eg. Polo earth strap above alternator;astra braided strap from g/box to chassis rail or batt neg to land panel;peug strap splitting to inner-wing and block.
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Tue 10 Dec 2002 14:05
Wierd battery behaviour - dan
Its a volvo 480T and has always needed a hefty crank to start it. I just wondered why you could get a lively crank and have no chance of starting it then use another source that gives a far more sluggish turn over but it starts after 2-3 'chugs'!
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Tue 10 Dec 2002 15:13
Wierd battery behaviour - RichardW
Had it stood for a while in the bodyshop?

It's probable that the hydraulic tappets had drained down, and needed 'pumping up' before the valves were doing the correct thing and giving you the compression (hence it appeared to turn over more easily). Once you have pumped the tappets up again, away it goes first time over.

Of course if you haven't got hydraulic tappets, then I haven't got a scooby!!

Richard
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Wed 11 Dec 2002 13:38
Wierd battery behaviour - Peter D
When the car has been started and run for 10 mins what is the terminal voltage of the battery. If this is over 15 volts then the battery is displaying a higher internal resistance and although you can obtain the correct electrolyte reading the high starting current can not be obtained. How olr is the battery ? 3 4 years old. Well could well be duff. Peter
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Mon 16 Dec 2002 15:45
Wierd battery behaviour - dan
No its only a couple of months old.
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