datnet.org: Electrical Problem - datnet.org

Seems like problem after problem....

Not only does the battery (new) drop to a very low 6 or 7 if left sitting for a week or so but when you drive it after a little while when the car heats up and the fans come on i loss power, if i leave it idling and watch it as the fans come on the engine seems to slow down/lose power. I just changed my alternator, does anyone have any ideas?

Thanks

woody

What is the 'S' terminal of your alternator wired to?

I hear lots of people giving advice to "just wire it direct to the battery" (or '+' terminal of the alternator), but from my experience this does cause the battery to drain between weekends.

I recommend doing as above, but put a relay inline, triggered by a source of IGN power (ie so that the connection is only made when IGN is on, but is O/C when keys are removed)

Make sense?

Also, depending how many cycles your NEW battery has copped, it may already be rooted. Lead acid batteries don't like cyclic discharge and can be killed quickly.


As for the fan problem, that sounds like voltage drop due to the current draw of the fans. Probably a bad connection, dirty switch contact, insufficient wire size or the like. Would need to look at that to diagnose the source.

PM if you want me to drop around. My rates are reasonable

SX-510, on Jul 1 2009, 07:50 AM, said:

Thanks mate, turns out (as i expected) that it was just the alternator so i've swapped back to the old one just to keep it going. It was the alternator that was draining all the power as well.

SX-510, on Jul 1 2009, 07:50 AM, said:

You are spot on there Jeff,
we have measured a current draw of 0.25amp with the S terminal connected direct.
Relay is the only sure way to do it correctly.
a 100 ohm resistor jumping the alternator warning light is also needed as the alt may not charge if the warning lamp globe fails.
This has also been know to fritz the alternator if run without load.