What do people do about the feed to the fan on a BEC, have mine on a permanent live feed and finds it flatens the battery pretty quickly so should I change it to be switched by the ignition. Cheers

The fan on my BEC switches on at 103 degrees so it never really comes on ( esp at the mo) - cant remember if its being switched by the ignition or permanent feed though.

What are you using to switch yours? and at what temp?

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If you're running a bike battery then considering they don't have much capacity it's best to use a switched supply.

Then again, if you're fan is coming on during cool down it suggests your engine is pretty toasty when you switch it off!!

Unless there's something else going on like arc'ing in the radiator fan switch or something.

Is the battery getting flattened by the fan running on after the engine is switched off?

yes fan drains after the car is switched off

does it come on at all when running?

Only when the car has been stationary for about 15min

does it switch off again once you start moving?

I think it will be fine when moving, have been running the engine alot stationary as I am going to SVA on tuesday, just worried I am going to flatten the battery half way through the test

mine switches off at 100 degrees so was wondering if yours is actually switching off or just coming on and staying on until the battery is drained.

BTW I have my car on charge when in the garage as BenB says there isnt much capacity in a bike battery and I have found mine drained a little a few times if left for a couple of weeks



P.S good luck with the SVA on tuesday

[Edited on 3/1/09 by 001Ben]

OOh yes me too. Optimate is a pretty important bit of kit for bike engines unless you're running them a lot during the week. I killed 2 bike batteries (before I got my optimate) by leaving the car in the garage with the battery slowly self-discharging....

When you're driving around the temp should be pretty low, the fan should only come on when you're stuck in traffic (ie stationary). Unless your garage is right next to a permanent traffic jam I wouldn't worry.

Have you got a water temperature gauge. One thing to do is when the car is cooling down and the fan is staying on switch on the ignition and see what temperature the water is at. It should be pretty high if the fan is still on.... If your water temperature sensor isn't close to the fan switch in order to get an accurate water temp reading you might need to switch on the engine for a few seconds to get the water circulating so that you know the water temp sensor and the radiator switch are "seeing" the same temperature.