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XR650r Cooling Fan with stock stator


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I am looking at adding a KTM cooling fan to my BRP. I only ride in the woods and trails and am wanting to just use the stock stator. My plan currently is to get a dc rectifier\regulator and add a small battery. Fan will be on  a manuel switch and used only when needed. Would I see improved fan performance by unhooking the taillight and headlight as i only ride in the day. Would love to hear some imput from anyone who has done the BRP this way. Thanks

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KTM fan eats much of energy, about as much as stock XRR headlight and taillight so stock stator has enough power for it, but yes, you should also make a switch to disable a headlight. Or else when you'll turn the fan on headlight will dim out to invisable and fan won't be spinning fast enough to make a difference.

Also, you don't really need a whole regulator/rectifier assembly, you just need to connect a cheap rectifier from any radioelectronics shop to the wires from your headlight. you connect wires from headlight to AC legs and get + and - DC 12V from + and - legs

You can find out which legs are AC and which are +/- in a shop or in any description of how it works, basically they all look like this, you need 50Ampere or less and a tape

 Square_Bridge_Rectifier.jpg

 

the shop with those rectifiers avalable should also have some good switches and wires, I don't recommend any plastic switches or buttons, those are not ment to endure trails on a bike  ?

You can use tape to stick the switch to handlebars or something or even put it's wires under one of rubber bands that hold a headlight

switches.jpg

Left - bad switch

Right - good switch

Edited by MCVL
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KTM fan eats much of energy, about as much as stock XRR headlight and taillight so stock stator has enough power for it, but yes, you should also make a switch to disable a headlight. Or else when you'll turn the fan on headlight will dim out to invisable and fan won't be spinning fast enough to make a difference.

Also, you don't really need a whole regulator/rectifier assembly, you just need to connect a cheap rectifier from any radioelectronics shop to the wires from your headlight. you connect wires from headlight to AC legs and get + and - DC 12V from + and - legs

You can find out which legs are AC and which are +/- in a shop or in any description of how it works, basically they all look like this, you need 50Ampere or less and a tape

Square_Bridge_Rectifier.jpg

the shop with those rectifiers avalable should also have some good switches and wires, I don't recommend any plastic switches or buttons, those are not ment to endure trails on a bike ?

You can use tape to stick the switch to handlebars or something or even put it's wires under one of rubber bands that hold a headlight

switches.jpg

Left - bad switch

Right - good switch

It should work, the stock output is rated for 60 to 80 watts, depending on the info source. I think you will need to 'unground' the stator windings, also called 'floating'. Maybe call Baja designs or trail tech.[/quote
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  • 6 months later...

Hi guys, I'm not looking to install a fan, but I did think my power process through so I could in future. I went with Fluidyne rads. Shouldn't have any problems unless I'm sitting totally still for ages which is something I don't generally do that much of. I've gone with a battery because almost all power requiring equipment will benefit from one. I've already installed the battery. It's a 3 cell 8000 mAh self managed lipo. It wont let itself be run flat and charges from a 3 to 30 volt DC input. Any battery will do, as long as it's protected from going flat if that matters for the battery type. My max charge rate (governed by the charger circuit board (part of the battery) is adjustable. Mine is 2 amps. I only need a small rectifier because of that, so I went with a 10 amp one. $3 from ebay for 5 of them. It doesn't matter how much juice fans want if I put them on now because the battery can supply heaps of power. It will only ever drain 2 amps (24 watts) That's a total of 75 watts with the headlight on, but it's not for long periods of time unless I'm absolutely hammering my battery. The stator will cope just fine. I'm using LED signal and brake lights. The extra 5 watts matters I think. No reason not to change to LED. My battery has a charger circuit board on the side. I formed up carboard and poured epoxy in to keep moisture, dust and vibration at bay. It sits in a standard XR tool bag which is mounted on my front fender right in front of the headlight. That's my perfect setup for you guys anyway. Always good to hear what other people are doing. I've learnt heaps on this forum..

Edited by 5mman
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I've put a Honda fan on my xr650r '00 ,think the fan was off a cbr from what I could see on the Internet,stock stator pulls the fan,headlight,tail light and horn no sweat,I've reduced engine temps from 100'c in traffic to around 70'c,no rectifiers or other gear required,wired it to the head light cable with a kill switch for on off,works like a charm

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It should work, the stock output is rated for 60 to 80 watts, depending on the info source. I think you will need to 'unground' the stator windings, also called 'floating'. Maybe call Baja designs or trail tech.

stock stator has a floating ground. this kit will give you a DC set up.

http://www.rickystator.com/product/stators/honda/honda-xr650-dc-charging-system

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I think I understand Rickys comment. The stator wires coming out of the engine are floating, meaning not grounded. The green wire in the harness is grounded, so the stator is grounded when it is plugged in. So you will have a floating system if you unplug the stator wires from the harness and run them straight to the input of a regulator/rectifier.

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I think I understand Rickys comment. The stator wires coming out of the engine are floating, meaning not grounded. The green wire in the harness is grounded, so the stator is grounded when it is plugged in. So you will have a floating system if you unplug the stator wires from the harness and run them straight to the input of a regulator/rectifier.

Correct Scott-M

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  • 3 years later...

Hey guys, just got a 650R, have the KTM fan with digital switch built in, came with the bike but not installed.  I read the comments above, does anyone have pictures or a diagram of how to hook up the power to the fan using the headlight wiring.  I plan on just disconnecting the headlight as I only ride during the day with my son.

 

Thanks,

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