Hello and thank you for reading. Assume I know nothing about batteries, electricity, heating elements, etc. I would like to learn how to safely heat up my cycling shoes in cold weather. I do not want to buy the heated insoles and other products available on the market. My cycling shoes are a little too tight for thick socks and insoles, plus those things are expensive and teach me nothing. I found this video on YouTube (link below). I like the general idea but many of the viewers commented that his methods are unsafe. Can someone recommend a book or place where I can learn the basic steps – in a few hours – of what I need to know, buy and do? Thank you!
I would not recommend you do this . . . there is a real risk of burning your feet. It takes expertise and access to the right materials to do this safely. Even if you were to make something that seemed to work in your home, things can go very wrong in actual use, and the results may not be good.
It may not be as fun as making your own, but the price of heated socks or soles is not that bad, and worth the peace of mind to not get second or third degree burns.
I have watched the video a few times but did not see him call out the voltage on the battery or the resistance of the wire. I would be interested in experimenting with this and not be afraid to try it but I did like the idea of having a potentiometer in the circuit to vary the resistance/heat to the individual or situation. I do not know where the battery would work best for a runner and their are some batteries more difficult/dangerous to work with than others.
I do not know of a quick way for you to get technical training to apply to this problem in particular but ohms law including the power portion covers most of my concerns.
Some of the comments after the video are just wrong the wire is insulated in the video, it is not a direct short etc.
feel free to check back some of the other techs may weigh in on this as well. If I try it I will post each item used.
So I did do some playing around with this on 01/22/21. If you use a long enough piece of wire you do not need a resistor in the circuit to prevent shorting because of the resistance in the wire.
Basic electronics says Voltage / by resistance = current. Power is what generates the heat so current multiplied by voltage = Watts.
What they had in that video is sound as far as the electronics goes.
There was a time when lithium batteries were very dangerous to work with and still can be if mishandled or purchased from an unreliable source.
If you have a good reputable brand the odds are you would need to be hit by a bus to explode one but if it happens it is catastrophic to anything near it.
However if you purchase a battery by price and don’t go with a quality vendor those risks increase.
The thought I had and hoped I could do was to use a safer battery but found current output is an issue with say the regular AA Alkaline battery.
Beyond that I found that walking on hand wound soles was not comfortable. Also the wires do move with use and the more wire in a given area the more heat in that area.
Depending on the wire used you will eventually wear on the insulation for the wire and could eventually create a shorting event
So in my opinion it is not comfortable , there is no recourse for injury when you make it yourself, and even if the risk can be minimized there still is some from wear.
I would not want to start experimenting with glues to hold wires in place because it could introduce more risk and the comfort already made me lose interest in making this a personal project that I would want to pursue.