PCM, battery and fans

[Craig 94 TA GT]

I know the fans suck a lot of juice, but was wondering how long the battery lasts, with the car off, and the fans running. This is because whenever I flash the PCM, or even read the current program, both fans kick on until the read/flash is finished. It takes several minutes for the read and flash too. I was afraid the battery would die, so I hooked up a charger to it, while it was flashing. Will the flash halt, if the battery dies in the middle of a flash? Or does the PCM have another form of power? I know if it quits, there goes the PCM, and I'd have to physically remove it, and get it shipped for repair.
Thanks in advance.

[Z Ya Later]

Ummm, I believe it will. At most, the PCM might have a small battery strictly to keep power present while the main battery is disconnected/drained. However, the fans shouldn't draw that much power I don't believe. But, I don't believe keeping it on the charger is a bad idea. I thought you already flashed the PCM with the new program? Problems?

[Craig 94 TA GT]

Nope no problems man. I'm just trying to get ready for the next flash lol. Also, when I was playing with the fan switch, the battery lasted about 8-10 minutes or so before dying...with both fans on. That was for testing the fan switch LEDs. Now I don't know if that's a rare case, or if it's because the alternator is giving a weaker charge, so the battery may be weak ...that's why I was wondering how long it normally lasts.

[N20LT4Bird]

I used to have one of my fans hooked to a toggle switch to run them with the electric water pump when the car was turned off in the pits, for my next race. I used to run the fan and pump for ten min. no problem.

[Rob B (shoebox)]

If your battery dies during programming, your PCM will be toast. There is no internal battery. Just pull the fan fuse or relays before you program and the fans won't run.

[Craig 94 TA GT]

Alright, thanks Rob. I never thought about pulling the fuse...I'll make sure to do it from now on!