# Heating Boots

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## Introduction: Heating Boots

My girlfriend often waits for a bus during 20-30 minutes. There is -5°C...-20°C sometimes. And today I want to show you my solution.

In the video you can see the test of this boots in beautiful New Year Helsinki.

Pleasant viewing :)

## Step 1: I Used:

1) Wool Insoles like this:

http://s.click.aliexpress.com/e/ccScfELQ

2) Heating Nichrome Wire. I used 0.4mm:

http://s.click.aliexpress.com/e/jL1nvwo

3) Batteries Li-ion 18650:

http://s.click.aliexpress.com/e/bnXXyPtQ

4) Power Bank Case (5V, 1A):

http://s.click.aliexpress.com/e/zRJrt9q

5) Hand made USB powered cable for 5V, 1A.

6) Sewing Elastic Rubber 40mm:

http://s.click.aliexpress.com/e/bdAQtCMu

## Step 2: Nichrome Wire.

I cut 65 cm of nichrome wire. It takes 5V, 0.7A for one foot. Insoles warm up to +49°С.

## Step 3: USB-cable

I tested some USB-cables, but they could transfer only 0.5A unfortunately. And I made my own.

## Step 4: Soles + Wire + USB-Cable

I sewed the wire and USB-cable to insoles. Nichrome wire couldn't solder, so i used needle with thread.

## Step 5: Batteries

I used new li-ion batteries 18650. I tested it's capacity = 3400mAh! It's great :)

Let's calculate battery live time.

Battery has 3.7v and 3400 mAh, but Power Bank voltage transformer gives 5V.

So battery into case should has capacity: 3.7*3400/5 = 2516 mAh.

The nichrome wire "eat" 0.7A, so battery live time: 2516/700 = 3,6 hours. Voltage transformer efficiency, I think, 90%, so we have 3,6*0,9 = 3,24 hours.

Will check it latter.

## Step 6: Temperature Test

I got 21°C (without nichrome wire) and 49°C (with). Cool!

## Step 8: Strap

I sewed straps using 40mm rubber and velcro.

## Step 9: Results

Hid under jeans :)

## Step 10: Conclusion

We tested heated boots in Helsinki on the New Year holiday. It is a beautiful city! But it was so windy.

We were walking about 8 hours every day. And these boots were saving Masha.

Masha is happy. Me too :)

Live test showed they are great boots, don't causes discomfort. Live time about 2-3 hours. We didn't check the exact time.
But USB contact was bad. I want to change it to other connector type.

PS: Sorry for my bad English, I am still learning. You can correct me (please).

PSS: It's my first instruction, so I will be happy to read your opinions ;)

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• ### For the Home Contest

Great idea. I'll try it with my dive suit.
BTW, where did you get that The nichrome wire "eat" 0.7A ?
thank you

The nicrome wires are specified by the resistance/ meter and sold by that. The Amps?? Again (I=A=Amp=current, U=V=Volt=voltage, R=Ohm=resistance) and P=U*I, I=U/R, R=U/I, so actually the nicrome wire doesn't "eat" the 0,7A@3,7V, instead it willproduce P (Power=Watt's)

Thank you!
I connected 65cm of nichrome wire (0.4mm) to battery and measured amps using my multimeter

Interesting idea to use nichrome wire as a heating element! There was an emphasis on learning a second language in American high school in the 1960's, but it is apparent that
Americans have become even more insular since then. It is now mostly American women who graduate from American colleges. I am glad that Finns are still interested in other languages!

Thanks for comment!
It's interesting to know somethings about Americans :)
But I'm not from Finland, I'm from Russian (Saint Petersburg). We celebrated New Year in Helsinki.
And nichrome wire is standard element in many heating things.

I should say that I am glad that Russians (and Finns) are still interested in other languages. This is the first time I have seen fine nichrome wire woven into clothing as a DIY project:) I usually think of nichrome as something difficult to work with, and carbon heating elements seem most popular for this kind of application..

Hi. (me FIN), I've never used "nicrome wire" ewer to anything. But still, I do do know about the "nicrome wire", (my bread-toster has one and I never heard a bread-toaster to blow-up). It's only and simply a "resistor" in a form of a wire. It only has it's resistance, ohms/ meter which is quite low. Thus giving a high P (Power) P=U*I, I=U/R. U we know = 3,7V, R we get from the specs. of the nicrome wire used/ meter. SO ELEMENTARY Geeeee...
So, 1Amp @ 3,7V= 3,7W, that I guess would warm up your fingers (toes) pretty comfortable.
To those saying the LiPo to explode? That would require ashortage directly on the poles of the battery, NOT the nic.wire.

Yes, carbon heating elements better for clothes

What about safety? I keep hearing about exploding li-ion's now and then. Doesn't that worry you?

When you talk on the phone, the Li-ion battery is millimeters from your face. Now what?

That's so wery true, I haven't seen in the News anyone to get hes face "BLOWN UP" because of talking on a Phone, yet.

Yes, I worry about that. But Power Bank has short-circuit protection inside. Besides we all use li-ion in our phones. I don't know what should happen for explode. Maybe I must put my leg into water knee-deep))) Or be crashed by car bumper...

I don't believe you will have any problem with water shorting because you're only using 5V, however it might just tingle your foot soles if you have standing water in the boot or sock. It would be similar to but less than the effect you get from sticking a 9V battery to your tongue.

Great! I have been trying to come up with something like this for decades, but I just never got to it until now.
Thank you very much from me and my cold feet.

I really like your 'Ible. It reminds me of times when I lived in a region that required such drastic measures (American Mid West).

Try using a USB-C cable. They are spec'd and designed to handle the higher loads. Just got a new Chromebook and it wouldn't mobile charge rapidly on regular USB adapters. Got the USB-C adapter and cable and now getting 2.2A charge!

Cheers!

Thank you!
But I don't need more then 0.7...1.0A :)

Last I checked, 2.0A is a bit more than 0.7 or 1.0. :-)

Very interesting project! Well done!

It's cool to see some other creators using AliExpress, I feel like it's really overlooked for the kind of deals it has. Especially using the power banks. I've got a few projects in the works using the same parts!