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Battery Not Charging...everything Else Okay!


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74 2002 manual, recently replaced radiator (only of interest because I removed the alternator to replace a hose.) Battery is good (new Bosch unit, decent quality big one!).


Straight out of the garage (on a trickle charger) starts up perfectly - I drove around 200 miles and stopped for fuel, got back in and the battery was nearly flat - just turns over, not enough to start. Assumed I'd left the lights on (but was suprised they'd drained the battery that fast). Got a jump start, easy first turn of the key. Drove a further 75miles (lights and wipers on), arrived a destination, stayed for 3hours... came out battery still dead, needed another jump start. Repeat for the return journey!!!


The lights, wipers and ignition obviously have power, but the battery is not charging. Before I start with the multimeter - any body experienced this before? Where should I start?





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Things to check:


1.  alternator ground wire (big brown wire that runs from the alternator frame to the bracket on the block that holds the alternator).  Check wire carefully--it can look intact on the outside and be nearly frayed through under the insulation


2.  3 wire plug on the back of the alternator--should be held in place with a wire bail--if the bail is missing it can--and will--come loose and still look OK visually.  Check the similar plug on the bottom of the voltage regulator too.


3.  When you turn your ignition on, does the alternator light in the instrument cluster come on?  If it's burned out or disconnected, the alternator won't charge. 


4.  is the alternator belt nice and tight?  If it's slipping at highway speeds, you won't get much charge then but will at lower speeds.


5.  Diode pack in the alternator may be bad; you'll have to take the alt to an auto parts store to have this checked.


I'm sure others will add more things to check...let us know whatcha find.



Edited by mike
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Solution was simple. (Idiot in charge of spanners.)

I hadn't tightened the +ve feed bolt on the alternator... Was red hot, huge voltage drop under load.... Cleaned, tightened and a new earth strap because the old one looked a bit worse for wear. Charging perfectly now.

Thanks for the suggestions!


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