A bad (almost new) alternator...
02-12-2013, 06:15 PM
#16
Rennlist Member
Talk about dead!
Do you have a cigarette lighter with wire ending in bare ends that you can connect the probes of a Digital Multimeter to. Twist the wire around the probe end and finish off with electrical tape.
Go for a drive. What does the voltmeter indicate now? Maybe your alternator is gone.
Of course charging up the battery by itself and when fully charged (assuming it'll take one), and then doing a simple load test will tell all.
Do you have a cigarette lighter with wire ending in bare ends that you can connect the probes of a Digital Multimeter to. Twist the wire around the probe end and finish off with electrical tape.
Go for a drive. What does the voltmeter indicate now? Maybe your alternator is gone.
Of course charging up the battery by itself and when fully charged (assuming it'll take one), and then doing a simple load test will tell all.
02-12-2013, 06:25 PM
#17
Nordschleife Master
I was able to slowvcharge the battery by itself last night to about 13.5V, enough to start the car. I think I could've charged it more but ran out of time. By morning though it had dropped to about 12V. I had to hop on a plane early this morning so I'll recharge the battery when I get home Friday and go for a drive with voltmeter connected as you suggest. I'll do a load test as well. Question: would a bad battery take a charge and then quickly lose it?
02-12-2013, 07:09 PM
#18
Race Director
I had checked the charging circuit myself previously on both vehicles and they were charging fine. I don't place a lot of faith in their load tests anymore.
02-12-2013, 07:53 PM
#19
Rennlist Member
It may or may not not take a full charge. And it may or may not lose its charge quickly. Any scenario is possible.
As for a load test being useless, its only one of the more important tests, but not the be all and end all. I've tested batteries that passed a load test, but only had 25% of their rated capacity. A battery's ability to start a vehicle (low internal resistance...a load test) is most important, whether it can keep your radio going for 48 hours (capacity) while parked is less important.
As for a load test being useless, its only one of the more important tests, but not the be all and end all. I've tested batteries that passed a load test, but only had 25% of their rated capacity. A battery's ability to start a vehicle (low internal resistance...a load test) is most important, whether it can keep your radio going for 48 hours (capacity) while parked is less important.
02-12-2013, 08:18 PM
#21
Rennlist Member
It may or may not not take a full charge. And it may or may not lose its charge quickly. Any scenario is possible.
As for a load test being useless, its only one of the more important tests, but not the be all and end all. I've tested batteries that passed a load test, but only had 25% of their rated capacity. A battery's ability to start a vehicle (low internal resistance...a load test) is most important, whether it can keep your radio going for 48 hours (capacity) while parked is less important.
As for a load test being useless, its only one of the more important tests, but not the be all and end all. I've tested batteries that passed a load test, but only had 25% of their rated capacity. A battery's ability to start a vehicle (low internal resistance...a load test) is most important, whether it can keep your radio going for 48 hours (capacity) while parked is less important.
