Alternator Help!!
#11
01-30-2007, 03:14 AM
RE: Alternator Help!!
BEFORE you fit a further replacement / repaired alternator you need to determine WHY the battery is flat otherwise you will likely get the same unsatisfactory result.
Top scenario is a defective battery. Get the battery checked UNDER LOAD by a dealer that specialises in replacement batteries / auto electrics. A voltmeter across the battery terminals does not tell you enough about the battery. You need to understand what happens as load is applied and what happens over time.
If the battery is OK then it went flat because it is not being charged adequately and each time you start the car or similar you gradually reduce the available power. (Its an accumulator not a battery to give it its proper name).
However something else may be draining the battery like an interior light or similar which does not go off. Once again you need to have this checked by an auto electrician who will determine what the continuous (quiescent) drain is from the battery when the vehicle is left overnight or possibly several days / month.
If the drain is considered acceptable lets say <0.1 amp then the next check is the alternator.
Whats is the output from the alternator supposed to be vs actual needs to be confirmed. Once again you need to measure the voltage but more importantly the amps coming from the alternator.
If all checks are OK there must be an intermittent short which could be dangerous. e.g. battery +ve lead to ground due to insulation damage.
The charging circuit is very simple "old fashioned" electrics and with the exception of the regulator, which is usually an integral part of the alternator dependent upon model / manufacturer etc there is no "high tech" digital stuff to make diagnosis difficult.
You didn't provide vehicle history as requested.
HOW OLD IS THE BATTERY? ONCE "JUMP" STARTED A BATTERY IS USUALLY ON ITS WAY OUT since if the voltage goes below 12.5 volts its IRREPARIABLY DAMAGED although it may stagger on for an extended period of regular light duty.
Hope this helps.
Stuart
Top scenario is a defective battery. Get the battery checked UNDER LOAD by a dealer that specialises in replacement batteries / auto electrics. A voltmeter across the battery terminals does not tell you enough about the battery. You need to understand what happens as load is applied and what happens over time.
If the battery is OK then it went flat because it is not being charged adequately and each time you start the car or similar you gradually reduce the available power. (Its an accumulator not a battery to give it its proper name).
However something else may be draining the battery like an interior light or similar which does not go off. Once again you need to have this checked by an auto electrician who will determine what the continuous (quiescent) drain is from the battery when the vehicle is left overnight or possibly several days / month.
If the drain is considered acceptable lets say <0.1 amp then the next check is the alternator.
Whats is the output from the alternator supposed to be vs actual needs to be confirmed. Once again you need to measure the voltage but more importantly the amps coming from the alternator.
If all checks are OK there must be an intermittent short which could be dangerous. e.g. battery +ve lead to ground due to insulation damage.
The charging circuit is very simple "old fashioned" electrics and with the exception of the regulator, which is usually an integral part of the alternator dependent upon model / manufacturer etc there is no "high tech" digital stuff to make diagnosis difficult.
You didn't provide vehicle history as requested.
HOW OLD IS THE BATTERY? ONCE "JUMP" STARTED A BATTERY IS USUALLY ON ITS WAY OUT since if the voltage goes below 12.5 volts its IRREPARIABLY DAMAGED although it may stagger on for an extended period of regular light duty.
Hope this helps.
Stuart
#12
01-30-2007, 12:12 PM
RE: Alternator Help!!
Whie you are having the alt rebuilt, strongly recommend you recharge bat. Also, make sure bat is full of water prior to charging. I happen to suse reverse osmosis water (as I do not care for the clorine taste) and suspect the contaminents of tap water build up inthe plates of bat.
Guy, see if that does not "keep" you on the road for while.
Retro Tom
Guy, see if that does not "keep" you on the road for while.
Retro Tom
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