So over the last few months I have gone through 3 mini batteries (odyssey) Car seems to drive fine and then the battery will die randomly. The last battery died while cruising home from the track on the highway... Lights start to flicker and that's it... the last battery lasted a day. I know everyone's first thought is going to be the alternator. I tested it at work the other day and it was putting out around 88amps. (stock is 90 if i'm not mistaken??) The car doesn't have a draw because it will sit for weeks at a time and start up fine. It only happens when the car is being driven. At this point i'm going to try a new alternator and see what happens because I can't think of anything else. New alternators aren't cheap... A shop we deal with at work said they can rebuild it for $150. What are your views on rebuilt alternators? Should I just buy a new one?

 

I would personally just purchase a new one and also change out the belt while your at it.

 

Have you checked to see if the alternator is actually CHARGING the battery? Having an alternator that works is only half the battle. If the wiring is kaput somewhere between the alternator and the battery, you've got a problem.

I'm typically not an advocate of just ordering parts and bolting them up. Especially in this instance where the problem could be a cheap (not simple) wiring fix. It's the difference between $20, and $200.

 

Try starting the car and pull off the terminals. If your car is dying while driving its not the battery imo.

Maybe try cleaning off the plugs on the alternator.

 

I will take a look at everything when I have it at the shop next week. I forgot to mention that I suspect its the alternator because when I was at the track last week i'm pretty sure I could hear the alternator whining.

 

Sometimes people are crazy with how complex they make things when trying to diagnose.

1. DO NOT DISCONNECT THE BATTERY FROM A RUNNING CAR! In simple terms, the battery acts as an electrical load stabilizer. If you disconnect it, you expose every piece of electrical equipment to surges. I know it's old school tech to suggest this, and it used to be good common practice, so I don't fault people for still touting it. But in a modern car, you're going to blow a buncha crap up.

2. Regarding making things complex. You can simply place a volt meter on the battery terminals prior to starting the car, and reading the voltage. Once the car starts, the voltage should be going up. If you want to test the functionality of the alternator, you can apply a load to the car's electrical system. Headlights on, fan motor on high, etc.

It's a simple quick test that gives you a good idea of where to begin the diagnosis. Although... I understand not everyone has a volt meter... but they're a good investment if you're doing any automotive electrical work.

 

^ yeah, I'm old. .

 

Haha! Who's not these days.

 

This. Smart and easy test. Personally im suspecting alternator also..

 

Check your alternator B+ wire. On my evo it corroded and broke off. Ate 2 new batteries until it finally broke off. I was in shock how it randomly happened. But anything is possible lol. G/l

 

Excellent advise. I read too often folks diagnosing the charging system by disconnecting the battery on a running car-- not a good idea.

 

good advice above, maybe check some relays if need be

 

Check plug going to alternator