Spring is approaching, which is incentive to get moving on installing heated grips. I'd been thinking of rolling my own grips and controller, because that sort of thing can be fun.
I started out by ordering a couple of these Pulse Width DC voltage controllers from Quality Kits in Kingston, ON (they do business internationally, by the way): http://store.qkits.com/moreinfo.cfm/MX033
I de-soldered the controlling potentiometer and relocated it to the end of a pigtail. An old Localtalk cable was perfect for such a task:
A piece of 1" heat shrink tubing was used to make a water-resistant boot for the potentiometer. I made a little hole for its snout to poke through, and welded the top shut by melting it a bit and squeezing it with needle-nose pliers. The bottom was shrunk and sealed with a zip-tie. Looks like a pig wearing a balaclava.
Note the board was trimmed a bit to fit in the project box, and the cable zip-tied to provide strain relief:
I bought a set of Kimpex under grip elements for this project. I bench tested them with the controller, and my multitester indicated two elements only drew 2.5 amps (~31 watts) at full power. Encouraged by a SV-lister who doubled his Kimpex elements up with good results, I decided to double mine up as well, two per grip.
In an effort to make a tidier install, I decided to solder one grip's leads to the other's pads (under the black tape). That turned out to be a bad idea -- I managed to destroy the solder pads on the recipient element.
I hadn't bought the second set of elements (for doubling up) yet. I decided to cut my losses and order a set of Oxford Heaterz on eBay for $60 shipped -- the same amount I'd pay for two sets of Kimpex elements. That is, if I don't get dinged too badly by customs. I'll decide later if I'll use the Oxford controller for the Oxford grips and use my contoller if the Oxford unit fails, or use mine outright. The Oxford Heaterz appear to be well built, with good looking strain relief on the wiring.
I modified two PWM controllers -- one with a short pigtail and one with a long pigtail. The short one was to control grips, to be mounted under the left front of the tank:
The long one was for future heated clothing, to be mounted to this bracket under the right side panel, where there is loads of room:
I wonder if the California bikes have the charcoal cannister tucked into that space -- that bracket looks very purposeful.
The controller + project box + misc. items runs about $35. Add $25 for a set of Kimpex elements, and the deal pales compared to the Oxford Heaterz, which can be had for about $60. The Heaterz appear to be better built, are probably hotter (company data indicates about 2.1 amps, or ~30 watts per grip -- twice the output of the Kimpex elements) and are likely better insulated from the handlebar.
I blew an additional $25 discovering that the Kimpex elements do not suffer the heat of a soldering iron.
For heated clothing, this is a good alternative to the well-built Heat-Troller, which runs $80 for a single, and $135 for a dual.
It would be easy to fit two boards in one case by removing the heatsink and placing the pot remotely. The mosfet and its heatsink did not get at all warm in the 10 minutes of bench testing.