Walmart Jacket - thin fleece for $10
About 2 yards of craft fusible interfacing material - $5 at Walmart (something like the link below)
https://www.walmart.com/ip/808-Craft-Fu ... /641470782
100' of 30 awg stranded hook up wire at Amazon - $15
https://www.amazon.com/gp/product/B0711 ... UTF8&psc=1
Speed Controller Motor with potentiometer, PWM at Amazon- $19
https://www.amazon.com/gp/product/B071W ... UTF8&psc=1
Coax Pigtail Power Connectors (5 pairs) at Amazon - $7
https://www.amazon.com/gp/product/B076N ... UTF8&psc=1
Battery tender fused ring connector at Amazon - $6
https://www.amazon.com/gp/product/B000N ... UTF8&psc=1
The idea is that this works on the resistance from the small wire and you use Ohm's law to calculate the wattage you get from a particular length of wire with a known resistance. The 30awg wire has a resistance of 0.1 ohms per foot. So, 40' gives you 4 Ohms. This gives you 3.43 amps from a 13.7 volt battery (13.7volts / 4 ohms) and 46.92 watts (3.43 amps X 13.7 volts). So, 2 in parallel should be roughly double which is 93.85 watts. That seems pretty consistent with commercially available jackets. A shorter length of wire will give you more heat.
I measured out two 40' sections and then routed the wire on one side of the interior of the jacket along the back, front, and sleeve forming loops that didn't cross about an inch apart. I held it down with blue painters tape and left the ends near the inside of the left pocket. Repeated with another 40' strand on the other side. I cut out sections of the fusible material to match the jacket sections and then damp ironed these on. This sealed the wires between the jacket and the fusible material and keeps the wire from being directly on you.
The wire is very thin and hardly noticeable when wearing the jacket.
I stripped the ends of the wire (hard to do without a 30g stripper) and soldered the ends to a coax pigtail I poked through the jacket pocket and knotted to keep it from pulling out. One end of the right side and one end of the left side to the positive and then the other ends to the negative. Shrink tube to water proof.
I wanted a power controller to be able to turn it off and to adjust the heat if necessary. You could simplify this and reduce cost by just going with an on/off switch. The one I got came with an enclosure and it turned off. There are cheaper and smaller options but they don't all turn off and then you need to craft or buy some enclosure. The one I got is a little larger than I would like. Anyway, I hooked the other end of the coax pigtail to the appropriate points on the controller. I used a standard SAE connector I had to connect to the battery inputs. Then, I used the fused Battery Tender SAE connector to the battery.
I've since ordered a 6 circuit fuse block so I can move all of my connections to the battery to this. Not really keen on removing the tank. Will probably switch the power leads to coax connectors when I do this.
To use it, I put the jacket on, connect the power controller to the jacket and then put the controller in my riding pants pocket. Motorcycle jacket goes on over the heated jacket. Then connect the SAE connector to the one on the bike connected to the battery. Then set the controller to the desired level of heat. I've not ridden in very cold weather yet so I can't tell how well the controller works. Overall, in 40's and 50's. it is very toasty, probably too much when it's warm. I need to drop the quilted liner from my jacket to get a better feel for how well it works.
Anyways, fun, easy project that seems to work and saved some $$$ on a commercial purchase: $62 vs ~$250. You could do it cheaper if you used a jacket you had, didn't need heat control, and already had an open connector on the bike. And like many of my projects, my wife thinks I'm crazy. Been suffering through Una-bomber jokes.
Some photos...
DIY Heated 12v jacket by acurley, on Flickr
DIY Heated 12v jacket by acurley, on Flickr
DIY Heated 12v jacket by acurley, on Flickr
DIY Heated 12v jacket by acurley, on Flickr
DIY Heated 12v jacket by acurley, on Flickr
DIY Heated 12v jacket by acurley, on Flickr
DIY Heated 12v jacket by acurley, on FlickrAndy
