Running fan on AC

I think if you have a close look at the wiring diagram you'll see that the regulator rectifier is a combined unit.

Usually motors are wound to either run on AC or DC, so I kind of doubt that you will be able to run that DC fan on AC.

The more common solution is to have the stator rewound for more power. My buddy who rides a KTM has sent his stator off to Baja designs and they did the following. The floated the neutral, and ran both legs of the generator output through and upgraded regulator/rectifier to the battery. And converted the lighting system to DC which should not be a problem as they are just fillamenets.

I am thinking about this mod myself, even though I can't run a fan with my stock tank. The reason is everytime I run my headlight with my tail light the connecting on the stator burns melts the soder off. If I just run the headlight it's not a problem.

Make sure that your battery is fully charged. Follow the instructions in your owners manual for charging instructions. Once the battery is fully charged, kick start your bike and put a voltmeter on your batttery, it should be reading in excess of 13 volts. Keep it running until the fan comes on. Watch voltmeter, at idle you'll see the voltage start to drop off. Now rev the motor up a bit and you should see the voltage stabilze and maybe go back up. Electric motors draw a lot of current and you are asking that one part of the winding to both charge the battery and run the fan, it's only good for 5.7amps.. So it's important to keep the battery charged, and keep the revs up a bit when the fan is running.

Hi Bigr,

I mounted an additional on/off switch on my 07/550.
Switch is an after market engine on/off-swicht (as seen on many Hondas road bikes, but anything will do)
Location: the water-hose into the cylinder-head (same diameter as handlebar),
easy to reach via the hole in the tank.
So, if the fan starts after stopping the engine -> just switch it off


I´ll try to post the pics within the next day

Are we talking about the regular fan? I don't know what amperage it is but if it drains the battery while the bike is running, then it's a bit odd.

Otherwise, a DC fan will simply not work on AC unless you have a rectifier of course. But then it will slow down when the engine is idling or going slow, basically when you need the fan the most.

I'd look for a drain and also make sure that battery is in good shape. Charge it all the way and look at the voltage. Do you have it on the charger all the time?

Hi, yes Mr Lefrog is correct these fans don't take much power and certainly shouldn't flatten the battery.
I am going to hook up two fans from a small Gas Gas TX50 the current draw from these two is very small.

Regards

Sparks.

Hi all,

I put a 12cm ZALMAN ZM-F3 - 0.35A PC fan, which I bound to a manual switch. I covered the electronics of the fan with enamel.
The power supply comes from one of the feet of the fuse.
The engine starts up with the starter when the fan is goes.

This solution is purse protective. 8)

Check my gallery to see how I did it. Although I'd rather have the fan(s) in a pull configuration (behind the rad), which is possible with the new tanks, both the Clarke and the new OEM tank, they seem to push a lot of air through.

I used the Vantec fans, which give about 120CFM each, for 1A used. 92mm PC fans. They're so loud they are usually for servers.

I'd put in a standard automotive relay to control the power to the fan. Just put the relay contacts is series with the fan and power the relay coil from directly across the AC. Most relays seem to handle running off AC OK so long as they don't have an internal diode connected across the coil.

One thing you can do is run the whole electrical system through the relay so that the battery doesn't go flat if you stop the engine and forget to turn off the key.

Not sure how the '07 is wired up but the earlier bikes have the relay already fitted with the coil turned on & off by the keyswitch. On these bikes you just have to reconnect the relay coil directly across the AC from the stator. I think you might also have to change where the starter switch power comes from then as the electrix won't come to life until after the engine starts.

Be aware that in some parts of the world road registration requires the tail light and park or headlight to remain on if the engine stops. Also, lights on is handy to help you find your bike when you go wheelsup in the dark! Your call if you want to negate this.

BundyBear, does the relay include pulse width modulation or any other type of voltage regulation?

G'Day Bigr,
I to have had the battery go flat with the factory fan fitted. The battery is new and was fully charged (I leave a maintenance charger on it all the time in the shed). The conditions though were perfect for sending a battery flat. We had a large group riding tight forest single trail with regular stops for slow riders and re-groups. Every start was with the button and the fan stayed on for about 1 minute at each stop. I was running 15/45 gearing so the revs were regularly low.
I have fitted a switch up on the bars to turn the fan off at re-groups and stops, and I am now running 15/50 gearing. The gearing change was more to suite the very tight and hilly conditions better, but will help to keep the revs up a little as well.
My next ride will confirm whether this works OK or not. If not then I will rewind the stator and perhaps do the mod that DaleEO has described above.

Cheers
Garry.

LeFrog said:

BundyBear, does the relay include pulse width modulation or any other type of voltage regulation?

Click to expand...

The relay is just a standard automotive relay with a coil driving a set of contacts - the same as those under the seat of most of the earlier e-start bergs. With what I described, voltage regulation is taken care of by the normal bike voltage regulator.

Bigr said:

I charged up the battery to 12.8 volts...

Click to expand...

Is that the battery voltage while it is charging or with the charger off? Typically the voltage with it charging should go to 14.2V or higher. With these absorbed electrolyte batteries the only way you can tell their state of charge is by measuring their terminal voltage after disconnecting the charger and allowing a few minutes for the voltage to settle. They should measure of about 13.6V at full charge. 12.8V would indicate it is less than half charged.

Bigr said:

The bike doesn't have a key so that option is out

Click to expand...

What turns off the rest of the electrical system when you stop the bike or does it not have any other electricals? Does it already have something that detects the engine is stopped? If so, can you use this on the fan as well?

Bundy, there are relays that also include a PWM board, like the SPAL unit.

From what the SPAL website says the PWM unit you refer to is a controller that varies the speed of a fan according to an input from a temperator sensor, not a relay. The relay that they use controls the second fan and it is just a simple Hella relay not unlike the ones in the 'bergs.

I run (or am trying to run) the SPAL fan controller. I've tried two relays of different coil capacities and two different bridge rectifiers to trigger the controller by AC (since the DC is always on). I've had no luck with any of them. The bridge rectifiers worked on one start up and then fried, one relay was sized to large (it had a 110 VAC coil) and wouldn't trigger at all, and the last relay (12 VAC coil) would trigger intermitantly. Ultimately not too surprising since the 'berg (FS650E in this case) only runs at 10 VAC. These relays were electromechanical, not solid state. Solid State might be the key if you could find one with a super low volt AC coil.....I never found one. Ultimately, I ordered a handlebar switch to trigger DC to the fan controller.

The only reason to run the fan controller is to keep from having to put a hole in my 2005 radiator.....and to gain precise control of the fan speed. Pretty expensive settup however, and I still haven't got it working the way I want it.....yet!!

r1addict said:

... the 'berg (FS650E in this case) only runs at 10 VAC.

Click to expand...

If you rectify the AC (put it through diode(s)) and put it across a largish smoothing capacitor you will get about 17VDC or more. While the RMS of the AC (what you would measure with a good meter) is only 10V its peak goes much higher due to the crazy waveform that results from the regulator. The rectifier/capacitor serves to hold the output at close to the peak voltage of the AC.

R1addict, the Spal PWM might really be overkill, as it is an automotive unit which provides gradual voltage control instead of the usual dual temp switches (low and high speed). It is also programmable, which is pretty neat, but it's only useful on cars and trucks, especially racing application.

Our fans pull one or two big amps, so really it is not really necessary to apply that type of control and basically it is an on/off thing.

That's why a simple temp switch is more than enough, IMHO.

Below is the Selco CA190 which I epoxied onto the radiator. I since move it behind the rad, under the tank, as I was a bit tired when I put it there and forgot about airflow.

Closes at 190, opens at 155.

Look on eBay. Look in my gallery.

Note: the epoxy can be removed easily with paint stripper.

Note 2: you can also make your own PWM based on a 555: http://www.nomad.ee/micros/pwm555.html

LeFrog, thanks for the link on the Selco. I actually looked at it early on and then forgot about it. Bit late now since I actually own the SPAL controller. Could have saved me a grip of cash by now if I had gone the Selco route. I can't really complain about the SPAL though, other than not being able to run it the way I want.

If you get it wired can you post something here?