Alternator charging voltage
Posted: Thu Oct 30, 2008 10:51 am
Looks like my Federal Battery I purchased in July 2007 is dying 
If the car sits for more than a week without being started it will start to crank over and slow down before it can start.
Second time this has happened, first time I thought the door had not been closed properly so I recharged it over night.
This time we had been away for a week and all doors were closed properly.
Last time I measured the current after it was charged at 17mA which is within specs (max 20mA) when not running.
Went to Battery World last night to get it tested, load test was ok and alternator was charging it at 14.6V at idle.
Battery is out of warranty and they claim 14.6V is too high and it is being over charged
car had been jump started so it was pumping 10A into the battery.
Workshop manual states alternator output as between 13 to 15V so it appears to be within spec.
Has anyone on here measured the voltage at the battery while the car is at idle (NB8B)
Battery has been on slow charge over night but was still drawing 1A (started at 2.5A) after 12 hours on the charger so its not looking good.
Looks like I may be purchasing a Supercharge Battery which has 3 years warranty at half the price the Federal was
If the car sits for more than a week without being started it will start to crank over and slow down before it can start.
Second time this has happened, first time I thought the door had not been closed properly so I recharged it over night.
This time we had been away for a week and all doors were closed properly.
Last time I measured the current after it was charged at 17mA which is within specs (max 20mA) when not running.
Went to Battery World last night to get it tested, load test was ok and alternator was charging it at 14.6V at idle.
Battery is out of warranty and they claim 14.6V is too high and it is being over charged
car had been jump started so it was pumping 10A into the battery.
Workshop manual states alternator output as between 13 to 15V so it appears to be within spec.
Has anyone on here measured the voltage at the battery while the car is at idle (NB8B)
Battery has been on slow charge over night but was still drawing 1A (started at 2.5A) after 12 hours on the charger so its not looking good.
Looks like I may be purchasing a Supercharge Battery which has 3 years warranty at half the price the Federal was