I'm having some charging problems on my '93 Civic, maybe you guys can help me pinpoint the problem.

For a few months, the battery light has been coming on/off during heavy rain with some belt slipping noise, so I thought it's ok and the belt is just not tensioned properly. It seemed to maintain a charge ok.

A few weeks ago, I drove it through heavy rain, and then the battery light came on again, and before I parked it after I got home, the light was on steadily. Then a few days later, it broke down at a stop light, battery was drained. We jumped started it, ran fine, and broke down again at the next stop light.

We then unhooked the battery, gave it a full night's charge with a charger, put it back in and started right up and ran fine. However, now whenever the rpm drops below 1500rpm, battery light comes on. Above 1500rpm, battery light is out.

It sounds like a bad alternator to me, but I can't be sure. What do you guys think? Are there any other possible causes that I should check for or beware of?

 

Sounds like an alternator to me as well. If you can get it to a shop that sells interstate batteries, they should have what's called a "ED-18" battery tester, it can fully test the entire charging system and will print out the results of the battery, alternator and starter; in many cases it will tell you what is wrong with an alternator that is not working properly. If that's not an option, my instinct would lead me to believe its the alternator. Which if my memory serves me correct sucks to do because you have to pull the CV shaft out on the side the alt. is on to get enough clearance to get it out, not that its a big deal just an added hassle that normally is not there.

 

Thanks, yeah it's a PITA to take the alternator out on this car since the space around it is so tight.

For the charging system test you have mentioned, is this the same stuff that's done at Autozone? I know they offer free alternator and battery tests, but wasn't sure if they're accurate or not

 

I'm not sure if they use the same type of tester, but any sort of test to assure your changing the right part is a step in the right direction. I am sure there are other good testers out there, I just have had fantastic luck with interstate tester, and the printout with graphs and all of the actual numbers of the car make it very easy to diagnose the charging system.