My battery was starting to die, so I pluged her in to the battery charger. What did I notice? The fans started coming on even with the key out of the ignition Weird. They would kick on and stay for about 20 seconds then shut off. Then they would turn back on in a few minutes. I haven't exactly timed it yet.

I just thought this was pretty funky I got the PFC and am wondering if it has anything to do with it, and no the fans never kicked on with just the FD sitting there, and no I don't have the fan mod done.

So has this ever happened to anyone else?

 

That's funny. You should disconnect the battery from the car and charge just the battery next time, not the entire electrical system.

 

Yada..............yada yada
But my hands will get dirty

Come on. I've never had that problem with any other car!! Oh well. I guess we really DO have funky cars.

 

I recharge all my cars every 2-4 weeks just about (just to keep the battery fresh) and this has never happened to me. Seems odd that they would cycle on and off like that.

 

Yep I've done it before too and haven't had any problems with the fans coming on.

 

You guys got PFCs? I'm wondering if that has anything to do with it being that the PFC itself can control when the fans kick on.

 

No I didn't have a PFC, sorry..

 

No PFC on my car, and no problems with the fans coming on when I hook up a battery charger. You may be right thinking that the PFC is the problem

 

I charge mine once a week with no problems at all. Could be the PFC, but that seems really odd too

 

Hey there FlyBye. I live in Ft Lauderdale, we ought to get together sometime. Anyway, I have PFC, and noticed the same thing. I did a fair bit of checking and it really seems like it's the PFC doing it. The only thing I could figure out is the PFC is turning on the fans to help keep the system voltage from going to high. It definately seems to be voltage related. I thought I was the only one to see this issue. I have an apexi FMIC and a lawn tractor battery, I was wondering if the little battery was part of the problem as it charges rapidly, and then I suspect the battery voltage goes way up. The PCF senses a high battery voltage condition and cycles the fans to lower it.

Jay

 

The timing of the fans coming on sounds a lot like your battery charger was cycling on and off, you know like some charges will vary the charging rate as the battery voltage rises.

Maybe the PFC does/can monitors engine temperature even with the key off and it ‘saw’ the relatively quick rise in voltage as high temperature.

If this is true it would probably only occur with a battery that has a bad cell because it drops the ‘normal’ voltage by 1.25 per cell. Then as the charger cycles, the PFC cycles the fan?????

Need to check with dealer or probably even the designer/programmer to know for sure if it works this way.

 

You probably need a new bettery. Have your charging system checked.

If you have a car alarm, there may be a sensor connected to your hood latch mechanism. If this is the case, an open hood may trigger the sensor. If you open your hood to let the engine cool after driving, this could cause your battery to be drained, especially if you leave it open over night.

 

im using the stock ecu

 

Question: So even if you're experiencing no ill symptoms of a dying battery, you should just charge it because. I noticed you guys do, I'm assuming they were fine before the charge as well. FYI I have the optima for 3 months, haven't felt anything bad since.

 

If your charging system is working correctly, and you don't have any electrical problems (like aftermarket devices that drain your battery), there should be no need to charge the battery.

 

Well, I had to charge my battery because i left a dome light on. Being that my FD stays in the garage, the dome light slowly killed the battery.

Now, this is NOT the first instance of this. 2 months ago (From the FD sitting in the garage for so long), I had to charge the battery up again, and the fans started cycling on and off again. I would take the FD for a spin for almost an hour or so, come back, reconnect the battery charger, and the fans would continue to cycle on and off. The cycle ONLY when the battery charger is connected. I've had the FD just sit, and with the temps up, the fans would stay on. and no matter WHAT position the ignition is in, the fans always seem to cycle with the battery charger connected.

By the way, the reason the FD sits so much is because I need to get it painted, and I currently have no funds to get it painted being that I working part-time to finally get school out of the way. The front end and one fender are a different color than the body, and almost the entire sunroof has an embarassingly large section of it missing paint. I refuse to drive in the day light like this. But late at night, when no one can see a thing, I occasionaly go hunting for victims

Yo yellowbird, like I said, I hardly ever take the FD out. Otherwise, I'd love to hang out with all the FD guys again. Thing is school is really getting in the way as well. I can't even remember when was the last time I went to Tower shops. I'm sure we'll hang out some time. One thing I hardly ever miss are the SCCA events