home made heated gear write up

bicycle_ben · 12-08-2009, 09:36 AM

i made a heated jacket liner for $6 plus stuff i had laying around and no i didnt catch my self on fire!

besides i own a soldering iron and a physics text book! how better to test out some high school physics equations than to wrap yourself in wires and put electricity through them?!

with these two equations and a mulit meter you can safely make your own heated gear too!

Voltage = Ohms x current
Watts = voltage x current

the first thing you need to do is figure out how warm you want your gear to be. we will measure the power in watts. watts dont mean much to most people except when we start talking light bulbs. now a light bulb is designed to make light and heat is just a byproduct but it helps give you an idea of how warm your gear will be. a 40 watt bulb is warm to the touch but a 100 watt bulb will burn your greasy little fingers. your gear wont get as hot as the light bulb because the heat from the bulb will be evenly spread over the surface of your gear. basically your gear will only get as warm as the lamp shade around your bulb.

just to give you an idea of where to shoot for, i made a jacket that is 52 watts and it really isnt warm enough to ride with it stand alone on 35 degree night rides.

ok now for some math!

we are going to start with the power you want and work backwards to arrive at the amount of wire you will need.

im going to assume that the people who care about the math will understand why we are doing what we are doing and those who dont understand, wont care and will just plug in numbers.

im going to do this all with example numbers and the assumption that your alternator will kick out about 13.8 volts while the bike is running.

first we need to know how many amps our gear is going to use like this:

50 watts of power wanted / 13.8 volts while charging = 3.62 amps needed

now we take the amps needed and find the resistance needed.

13.8 volts while charging / 3.62 amps needed = 3.8 ohms of resistance needed in your wire

30 gage wire seems to be ideal for making heated suits because it gets warm but not too warm with a reasonable length of wire. the FATTER and SHORTER your wire the HOTTER it will get. if you use 26 ga wire you will need 90 something ft of wire to make a 50 watt suit and trying to sew 90 ft of wire to a vest would be a royal pain. if you ran 30 ft of 26 ga wire you would have a 150 something watt suit which seems a little warm but who am i to judge?

i found 30 ga Kynar insulated wire wrap wire which does the job nicely. the insulation is rated up to 220 degrees f which means it will burn you long before it melts off onto your skin or jacket. (thats a good thing)

anyway we need to measure the resistance of your wire. hopefully your wire will be exposed on both ends so you can test it without unraveling the whole thing. set your multi meter to the smallest ohms setting you have(likely around 200 and the symbol looks like a horse shoe). now we need to know the resistance per foot of wire.

50 ft of wire tested / 5ohms resistance measured = .1 ohm per foot of wire

we calculated how many ohms of resistance we needed and we know how much resistance we have in our wire per foot so we can figure out how much wire we need to use to get the power rating we wanted.

3.8 ohms needed / .1 ohm per foot of wire = 38 ft of wire needed

now you need to stick this to something. you could use a jacket liner or buy a vest at good will or whatever you wanted. i sewed my wire to my removable jacket liner. if you have a sewing machine use nice big zig zag stitch and that will hold the wire to the cloth nicely. you could also put the wire in a big fat sewing needle and stitch it right into the jacket if you wanted. iron on sewing patches might also work.

before you get sewing make sure to do a mock up of where all your wire will go so that you get more of the wire on the front of the jacket where you want the heat and symmetric distribution of the wire side to side.

my dad is a model!

i tested to make sure i could sew over the wire with a zig zag and not hit the wire

i taped the wire on to get it all situated before i started sewing

i sewed right over the tape and then pealed it off later

once you get the little wire stuck on you need to wire up a plug for this thing. i used nice fat lamp cord and soldered the ends for a good connection. i also put butt connectors over the connections and crimped them for a little extra strength. i sewed nylon webbing over the connections to make sure they didnt get pulled out.

you should put in an on/off switch at very least but you could get crazy and put in a dimmer switch or a pull width modulator if you wanted too. either way you need something to turn it on and off with and a way to un plug from your bike. you should add an in-line fuse to it that is fused just above the amp rating that you expect your gear to take. that way if something goes wrong it will pop before you do! also make sure you think about how long of a wire you need so its long enough to move around but not too long and in the way.

you should take this out to your driveway and test it BEFORE you go ride with it.

if it smokes thats bad and you should fix it ( i just had to burn up 1ft of wire to see what would happen )

dont blame me for anything stupid you may have done! now go ride with your new heated gear!

BentBike · 12-08-2009, 09:53 AM

yay for math.

I remember doing that stuff in high school and college. Good old math.

w=v*a

Oh, looks pretty nice. You should cover the wire up with some reflective stripping. That would look cool.

BentBike · 12-08-2009, 09:53 AM

oh wait...thats the jacket liner.

pjd · 12-08-2009, 09:54 AM

I vote your custom title goes from "WMRRA Qualifier" to "MacGyver".

That's really cool. And even cooler if you've been able to use it without fusing your jacket liner to your flesh or haven't blown out the electrical system on your bike.

I see a side business in your future.

SRWitt · 12-08-2009, 09:57 AM

Hmm maybe some heated seats for the ride, now that would be sweet.

bicycle_ben · 12-08-2009, 10:01 AM

Originally Posted by pjd

I vote your custom title goes from "WMRRA Qualifier" to "MacGyver".

That's really cool. And even cooler if you've been able to use it without fusing your jacket liner to your flesh or haven't blown out the electrical system on your bike.

I see a side business in your future.

haha Macgyver fits me, i have zip ties and duct tape on hand almost constantly

id happily make custom heated gear these days because right now it wouldnt be a side business

BentBike · 12-08-2009, 10:02 AM

Originally Posted by pjd

...I see a side business in your future.

Yes, now all he needs to do is find out a way to mass produce them

No need to full jackets, just jacket liners with this "heater" attached.

Hawker · 12-08-2009, 10:08 AM

I noticed you ran some of the wire down the selves of the liner. Are you concerned at all about the wire fatiguing and breaking over time?

nighthawker · 12-08-2009, 10:12 AM

this is nice.. i just bought a heated liner and id like something to cover just over my knees down to my boots. this DIY might just be right. ive got all the tools and proibably the right wires and ends..

thank you for your writings.
4stars

bicycle_ben · 12-08-2009, 10:29 AM

Originally Posted by Hawker

I noticed you ran some of the wire down the selves of the liner. Are you concerned at all about the wire fatiguing and breaking over time?

not really. the zig zag stitch gives the wire plenty of room to flex so it wont be flexing at just one point and the truth is i might end up clipping out the arm wire any way to make the rest of the vest hotter

dragracer1951 · 12-08-2009, 10:44 AM

I'd think about an in line fuse....

nighthawker · 12-08-2009, 10:45 AM

Originally Posted by dragracer1951

i'd think about an in line fuse....

bicycle_ben · 12-08-2009, 10:52 AM

oh yeah i put a 7.5a in-line fuse in there - let me go back and add that to the write up

beansbaxter · 12-08-2009, 10:55 AM

Originally Posted by pjd

I vote your custom title goes from "WMRRA Qualifier" to "MacGyver"

Originally Posted by dragracer1951

I'd think about an in line fuse....

bicycle_ben · 12-08-2009, 11:08 AM

haha awesome !

bukwld · 12-08-2009, 11:11 AM

awesome write up! This may be a fun winter project to try.

recr8ton · 12-08-2009, 11:32 AM

Awesome write up! ...I'll be dropping my jacket liner off with ya this weekend

Desvio · 12-08-2009, 11:43 AM

bicycle_ben, you rock. From a little Q&A and some hazing on the original thread, to finishing without going up in a puff of smoke. I would most likely would have burned something down, so, I'll just stick to sewing custom gear and repairs (like Martha Stewart on crack!).

Now imagine all those zip-out liners that are going to start showing up at your front door for 'upgrading'.

Sirena · 12-10-2009, 10:21 PM

Nice Job MacGyver!!
now you just need to go back and change the $6 part your post so you can charge more when those vests start showing up on your doorstep

Thanks for the great write up and pics!

Brady · 12-10-2009, 10:30 PM

awesome job Ben! Don't be surprised if that goes missing next Tuesday


12-08-2009, 09:36 AM	#1
bicycle_ben Joined: Jun 2007 From: beavercreek, or I Ride: a suzuki RF900R and a bicycle :)	home made heated gear write up i made a heated jacket liner for $6 plus stuff i had laying around and no i didnt catch my self on fire! besides i own a soldering iron and a physics text book! how better to test out some high school physics equations than to wrap yourself in wires and put electricity through them?! with these two equations and a mulit meter you can safely make your own heated gear too! Voltage = Ohms x current Watts = voltage x current the first thing you need to do is figure out how warm you want your gear to be. we will measure the power in watts. watts dont mean much to most people except when we start talking light bulbs. now a light bulb is designed to make light and heat is just a byproduct but it helps give you an idea of how warm your gear will be. a 40 watt bulb is warm to the touch but a 100 watt bulb will burn your greasy little fingers. your gear wont get as hot as the light bulb because the heat from the bulb will be evenly spread over the surface of your gear. basically your gear will only get as warm as the lamp shade around your bulb. just to give you an idea of where to shoot for, i made a jacket that is 52 watts and it really isnt warm enough to ride with it stand alone on 35 degree night rides. ok now for some math! we are going to start with the power you want and work backwards to arrive at the amount of wire you will need. im going to assume that the people who care about the math will understand why we are doing what we are doing and those who dont understand, wont care and will just plug in numbers. im going to do this all with example numbers and the assumption that your alternator will kick out about 13.8 volts while the bike is running. first we need to know how many amps our gear is going to use like this: 50 watts of power wanted / 13.8 volts while charging = 3.62 amps needed now we take the amps needed and find the resistance needed. 13.8 volts while charging / 3.62 amps needed = 3.8 ohms of resistance needed in your wire 30 gage wire seems to be ideal for making heated suits because it gets warm but not too warm with a reasonable length of wire. the FATTER and SHORTER your wire the HOTTER it will get. if you use 26 ga wire you will need 90 something ft of wire to make a 50 watt suit and trying to sew 90 ft of wire to a vest would be a royal pain. if you ran 30 ft of 26 ga wire you would have a 150 something watt suit which seems a little warm but who am i to judge? i found 30 ga Kynar insulated wire wrap wire which does the job nicely. the insulation is rated up to 220 degrees f which means it will burn you long before it melts off onto your skin or jacket. (thats a good thing) anyway we need to measure the resistance of your wire. hopefully your wire will be exposed on both ends so you can test it without unraveling the whole thing. set your multi meter to the smallest ohms setting you have(likely around 200 and the symbol looks like a horse shoe). now we need to know the resistance per foot of wire. 50 ft of wire tested / 5ohms resistance measured = .1 ohm per foot of wire we calculated how many ohms of resistance we needed and we know how much resistance we have in our wire per foot so we can figure out how much wire we need to use to get the power rating we wanted. 3.8 ohms needed / .1 ohm per foot of wire = 38 ft of wire needed now you need to stick this to something. you could use a jacket liner or buy a vest at good will or whatever you wanted. i sewed my wire to my removable jacket liner. if you have a sewing machine use nice big zig zag stitch and that will hold the wire to the cloth nicely. you could also put the wire in a big fat sewing needle and stitch it right into the jacket if you wanted. iron on sewing patches might also work. before you get sewing make sure to do a mock up of where all your wire will go so that you get more of the wire on the front of the jacket where you want the heat and symmetric distribution of the wire side to side. my dad is a model! i tested to make sure i could sew over the wire with a zig zag and not hit the wire i taped the wire on to get it all situated before i started sewing i sewed right over the tape and then pealed it off later once you get the little wire stuck on you need to wire up a plug for this thing. i used nice fat lamp cord and soldered the ends for a good connection. i also put butt connectors over the connections and crimped them for a little extra strength. i sewed nylon webbing over the connections to make sure they didnt get pulled out. you should put in an on/off switch at very least but you could get crazy and put in a dimmer switch or a pull width modulator if you wanted too. either way you need something to turn it on and off with and a way to un plug from your bike. you should add an in-line fuse to it that is fused just above the amp rating that you expect your gear to take. that way if something goes wrong it will pop before you do! also make sure you think about how long of a wire you need so its long enough to move around but not too long and in the way. you should take this out to your driveway and test it BEFORE you go ride with it. if it smokes thats bad and you should fix it ( i just had to burn up 1ft of wire to see what would happen ) dont blame me for anything stupid you may have done! now go ride with your new heated gear! __________________ Follow PNW Riders on Facebook and Twitter Last edited by bicycle_ben; 12-08-2009 at 10:55 AM..


12-08-2009, 09:53 AM	#2
BentBike Training Wheels Joined: Nov 2009 From: Lynnwood, WA Blog Entries: 2 I Ride: Hyosung Sense	yay for math. I remember doing that stuff in high school and college. Good old math. w=va Oh, looks pretty nice. You should cover the wire up with some reflective stripping. That would look cool. __________________ Follow PNW Riders on Facebook* and Twitter


12-08-2009, 09:53 AM	#3
BentBike Training Wheels Joined: Nov 2009 From: Lynnwood, WA Blog Entries: 2 I Ride: Hyosung Sense	oh wait...thats the jacket liner. __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 09:54 AM	#4
pjd Joined: May 2007 From: Milton I Ride: Soozookee	I vote your custom title goes from "WMRRA Qualifier" to "MacGyver". That's really cool. And even cooler if you've been able to use it without fusing your jacket liner to your flesh or haven't blown out the electrical system on your bike. I see a side business in your future. __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 09:57 AM	#5
SRWitt Superbiker Joined: Nov 2005 From: Rathdrum, ID I Ride: cause I'm a Loowwlife	Hmm maybe some heated seats for the ride, now that would be sweet. __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 10:08 AM	#8
Hawker Pit Crew Joined: Apr 2006 From: Seattle, WA I Ride: Too many	I noticed you ran some of the wire down the selves of the liner. Are you concerned at all about the wire fatiguing and breaking over time? __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 10:12 AM	#9
nighthawker Knee Dragger Joined: Mar 2009 From: sutherlin, oregon I Ride: as long as i can before i can no longer	this is nice.. i just bought a heated liner and id like something to cover just over my knees down to my boots. this DIY might just be right. ive got all the tools and proibably the right wires and ends.. thank you for your writings. 4stars __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 10:44 AM	#11
dragracer1951 Joined: Sep 2005 From: Bremerton I Ride: 05 KTM 625smc, 03 Are See fiddy one, 05 DRZ470SM, 95 FZR1040, 69 Combat Commando Roadster, 73 Commando Interstate, 67 BSA B44, 71 BSA B50	I'd think about an in line fuse.... __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 10:52 AM	#13
bicycle_ben Joined: Jun 2007 From: beavercreek, or I Ride: a suzuki RF900R and a bicycle :)	oh yeah i put a 7.5a in-line fuse in there - let me go back and add that to the write up __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 11:08 AM	#15
bicycle_ben Joined: Jun 2007 From: beavercreek, or I Ride: a suzuki RF900R and a bicycle :)	haha awesome ! __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 11:11 AM	#16
bukwld Joined: Sep 2007 From: I reside in between Heaven and Hell I Ride: the 08 Gixxer 1K that I act like I can ride..	awesome write up! This may be a fun winter project to try. __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 11:32 AM	#17
recr8ton Novice Racer Joined: Mar 2007 From: Portland/Beaverton I Ride: like a sniper at your back door!	Awesome write up! ...I'll be dropping my jacket liner off with ya this weekend __________________ Follow PNW Riders on Facebook and Twitter


12-08-2009, 11:43 AM	#18
Desvio Joined: Mar 2008 From: SE Portland / Bucerias, Nayarit Mx I Ride: 03' CBR1100XX, 84 GL1200A	bicycle_ben, you rock. From a little Q&A and some hazing on the original thread, to finishing without going up in a puff of smoke. I would most likely would have burned something down, so, I'll just stick to sewing custom gear and repairs (like Martha Stewart on crack!). Now imagine all those zip-out liners that are going to start showing up at your front door for 'upgrading'. __________________ Follow PNW Riders on Facebook and Twitter


12-10-2009, 10:21 PM	#19
Sirena Pit Crew Joined: Jun 2008 From: Portland, OR I Ride: Ducati Monster 620 & Yamaha Vino 125	Nice Job MacGyver!! now you just need to go back and change the $6 part your post so you can charge more when those vests start showing up on your doorstep Thanks for the great write up and pics! __________________ Follow PNW Riders on Facebook and Twitter


12-10-2009, 10:30 PM	#20
Brady Novice Racer Joined: Jul 2008 From: Hillsboro, Oregon I Ride: like the wind bullseye	awesome job Ben! Don't be surprised if that goes missing next Tuesday __________________ Follow PNW Riders on Facebook and Twitter

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