DIY heated clothing - noob needs help

[hjns]

Hi all,

Winter is coming, and it's cold when going 65kmh. So I did some surfing for heated clothing, and arrived here:
http://www.mototour.us/technical/electricclothes.htm

Now, I am an electronics noob, so I have some basic questions.
Essentially, the idea is to have a small 32AWG teflon coated heating wire woven into my jacket.

I like this one: https://www.distrelec.ch/ishop/Datasheets/05545009.pdf

I plan to weave about 10 meters of this wire into my jacket. Then connect it to a fuse and 5A 12V DC converter. I expect the 10m 32AWG wire to have a resistance in the range of 3 Ohm, and that it will heat up when pulling 5A. My idea was to be able to adjust the amount of heat by adding a potmeter in series.

I was thinking about this one with a resistance rate between 5 Ohm and 25 kOhm: http://www.schukat.com/schukat/pdf.nsf/index/3487DAF0BF91036DC1256F9C0033BB4F/$file/E_AW_2010_GB.pdf

Obviously, with a 25kOhm resistance, current would be near zero, resulting in no heat.
With the potmeter at 5 Ohm, and the wire also at 3 Ohm, current would be 1.5A (12 V/8 Ohm).
This would give a power of 18W, 3/5th of which is turned into heat, aka 10.8W

If I leave out the Potmeter altogether, I will get 4 Amps = 48W of heat, which may be too much.

Would that work?
A potmeter with a lower resistance would allow for more current through the wire. Any suggestions for potmeters that are within a reasonable budget (around 10-15 USD) ?

 

[Ykick]

If you're building from scratch why bother with 12V? I've been noodling with some designs using traction battery voltage around 60V in my situation.

For temp control I believe simple PWM circuit is the way to go. Jeremy and other gurus have spoken of this method for controlling and regulating passive heat devices. 'haven't built a circuit yet myself but it doesn't appear too daunting and should be much more efficient than shunting current through a power potentiometer. If that's what you're referring?

Electrically heated clothing and accessories will no doubt become more and more common and needed as eBikes continue to grow in popularity.

 

[neptronix]

How much heating do you require? these would be an interesting start if you are in a mild climate;

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=19740

 

[Farfle]

Find the average wattage of some other clothing, do some V=IR math and buy some nichrome resistance wire of the correct gauge and wire it up in two different sections and then wire a toggle switch to series/parallel the wires for low/hi heat.

 

[amberwolf]

See my suggestions in the recent threads about heated clothing/gloves and winter riding, etc. you can use the heater wiring from thrift store electric blankets or heating pads, etc. maybe even the controls.

 

[hjns]

Thanks all for the responses.

@Ykick, I would like to keep at 12V, because I fear frying myself when I connect a wire to my 84V Lipo. I have the DC converter onboard, and don't want to carry yet another piece of electronics around.

The PWM is a good idea though. I will look into it.

@Neptronics, we'll get snow tomorrow, and -10 centigrees is not a rare event. I looked at the HK heater, and it would be nice for my Lipo packs. I am pretty sure it's not enough for me. Thanks anyway.

@Farfle, I like that, because it allows for easy experimentation. Low would be with the nichrome in series, high would be without. Very KISS.

@Amberwolf, yes, that's why I got interested in the first place. However, I don't have any electric blankets or heating pads, and it's rather easy to a this teflon wire delivered to me....

I will post the results.

 

[Lebowski]

I once made electrically heated trousers for on the motorbike. Worked like a charm, at -2 C they got so
warm that I had to switch 'm off at the traffic lights.

I basically used standard plastic coated thin gage wire like I use for all my projects. I put 1A through a meter
of it, measured the voltage and then figured out I need 23 meters for 60W. I got some old pyama trousers,
laid the wire on it and with a sowing maching stitched it together with a zigzag stitch (with the wire
running in the middle. For control I used a very simple multivibrator with variable duty cycle (by potentiometer).
Worked like a charm ! After that I made heated boot inserts from computer flat cable, running the current
back and forth to get to the desired length/wattage.

I offered my GF to make an electric heated seat for her car. Got the circuit all ready, told her I would
sow the wire in a towel to put over the seat, I only needed to measure the width of her butt. This is
when the project ground to a sudden halt....

 

[hjns]

......I offered my GF to make an electric heated seat for her car. Got the circuit all ready, told her I would
sow the wire in a towel to put over the seat, I only needed to measure the width of her butt. This is
when the project ground to a sudden halt....

You should have married her. I can take my wifes measures anytime (of course after the obligatory footmassage, doing the dishes, etc)

 

[hjns]

I once made electrically heated trousers for on the motorbike. Worked like a charm, at -2 C they got so
warm that I had to switch 'm off at the traffic lights.

I basically used standard plastic coated thin gage wire like I use for all my projects. I put 1A through a meter
of it, measured the voltage and then figured out I need 23 meters for 60W. I got some old pyama trousers,
laid the wire on it and with a sowing maching stitched it together with a zigzag stitch (with the wire
running in the middle. For control I used a very simple multivibrator with variable duty cycle (by potentiometer).
Worked like a charm ! After that I made heated boot inserts from computer flat cable, running the current
back and forth to get to the desired length/wattage.

Love that. So you are saying it doesn't really matter what wire one uses, as long as you use the right length?

 

[Lebowski]

Correct. And use a pwm based controller for the power, not a simpel potentiometer.

 

[grindz145]

Dude, I have to tell you I tried, and did this. It was NOT a good idea.

- I installed NiChrome wire in my motorcycle jacket, and lit it up. Not bad at first...
-I ended up with hot spots shorts, and inevitably little pieces of wire stuck in my jacket for years

Buy a good quality heated jacket (ideally gerbing, they refirbish the clothes for free, for life)

I would say it might be a good idea since you found nochrome which is ALREADY coated with teflon, but honestly, the mass manufactured liners are hard to beat and for about $100 why bother?

The major manufacturers have went to this microwire construction which makes them way more robust and comfortable. I have to say, they are worth every penny for a series northern rider

 

[ohzee]

I took an older jacket last night found a big needle used some 30awg teflon coated wire and then held it in place with some iron on
heat bond. hooked it up to 12v and used the controller below to regulate the heat.

http://www.ebay.com/itm/290790282510?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Works great.. can adjust however I like and at high it's a bit toasty. I was able to just weave the wire thru the liner so it stayed
about where I wanted it and applying the heat bond helped keep it where I wanted.

Plan on doing the same with a pair of pants now. The controller made all the difference as without it the wire is just too hot
hooked up directly.

Here's the jacket.

 

[hjns]

Hi Ohzee,

Thanks for the link. I ordered two of them. I also ordered 30m 32AWG teflon wire. I will be weaving it with a needle into the current lining of my motor wear.

The plan is for a pair of gloves (1m wire for each), a pair of boots (1m each), a trouser (10m), a jacket (10m), and a helmet lining (2m). The PWM controllers are for the jacket and helmet lining. The rest will be an on/off affair. Switches will be attached to the steering wheel, so I can activate it only when needed.

Costs: 40 (including free shipping) for 2 controllers, and 50 for the wire.

 

[Gordo]

We ran with heated clothing for years. Bought some, built some. Crimps at the Nichrome/plug interface require careful attention. I would not power clothing with more than 24V. Sliding along in the rain in a 100V jacket does not appeal to me. It might keep your heart going, but also might stop it? Never used a pot to waste power. PWM is the way to go.

 

[hjns]

Two of these pwm controllers have come in.

I have 5 blocks of 25feet 30AWG teflon stranded wire. I am inclined to connect it to a 18.5V 5S 5Ah lipo pack with a 5A fuse, to get a 90W heat generator that will work at 80% for at least one hour (2x my 30 minute commute).

To keep my fingers warm, I would estimate 50cm of wire for each glove, as described here. I plan to connect those glove wires in parallel with 6x 1m of wires in the jacket liner. That would bring 6m of wire in the jacket, and 1m of wire in the gloves. As the wires are in parallel, length between the battery poles remains short (1m), allowing for a quick change in temperature, to be adjusted with the PWM controller. I will need some high resistance wire in series to keep maximum current lower than 5A and thus prevent blowing the fuse.

For a 5S pack HOC, it means 21V. At 5A, I should have a total resistance of 4.2Ohm (21V/5A). This would mean I would only need 4cm of this 100 Ohm/m Konstant resistance wire in series.