Alternator Problem (EG Civic)

**dorikin** · 20-11-2010 05:43 PM

I don't have a load tester unfortunately..

Ok did some more reading and supposedly you're not meant to load up the charging system on idle, only on fast idle (2000 RPM) so did another test.

Test 3:

Car on with high idle 2000rpm (no load) = 14.71V

Car on with high idle 2000rpm (with load hi-beams, heater, fan, stereo, demister, etc) = 13.90V

Is this acceptable for the charging system?

**na-118** · 20-11-2010 06:04 PM

1500 rpm not 2000

**GenesisEG** · 20-11-2010 07:41 PM

Sounds fine.

My guess is there's something running that's draining the battery between uses. I have the same problem, and I think it's my alarm.

Check the current draw on the battery with the car turned off.

It could be a light that's not turning off, or an alarm that's drawing too much current to run. Could also be an earth leak that's slowly draining the battery all the time...

Power problems are not always supply issues, it could be a constant drain, and it's probably easier to check that than it is to check the alternator beyond what you've already done.

**dorikin** · 21-11-2010 04:12 PM

Originally Posted by na-118

1500 rpm not 2000

There wasn't much difference at 1500 rpm.

Car on (no load) @ 1500rpm 14.58V
Car on (full load) @ 1500rpm 13.82V

Does the alternator sound like it's doing its job?

Originally Posted by GenesisEG

Sounds fine.

My guess is there's something running that's draining the battery between uses. I have the same problem, and I think it's my alarm.

Check the current draw on the battery with the car turned off.

It could be a light that's not turning off, or an alarm that's drawing too much current to run. Could also be an earth leak that's slowly draining the battery all the time...

Power problems are not always supply issues, it could be a constant drain, and it's probably easier to check that than it is to check the alternator beyond what you've already done.

That was my second guess, some sort of electrical draw while the car is off. I'll have to run some more tests. Do you know what the maximum electrical draw allowance is for a Civic? From what I've read the general rule of thumb is 50mA one hour after car has been turned off.