At this time of year in the UK we have some fabulous days for sailing with clear blue skies but oh it can be COLD😠. One day last week the temperature on the lakeside was -1C. I find after an hour or so I can't feel my fingers. I like to sail with fingerless gloves, which is part of the problem. I've tried using a transmitter 'muff' but find it doesn't make a lot of difference to my finger ends, and it is awkward when launching/recovering a boat as you can't quickly adjust the controls while trying to also get hold of the boat.
Looking round for a solution on-line, I came across heated gloves and thought I'd give them a try. They are designed to plug into a USB port on a computer (not very practical at the lakeside!), or a portable powerbank. Looking at powerbanks, I found lots of wild claims regarding the battery capacity available. The claims made for the low cost units were not credible, and the more professional units cost 3 - 4 times the price of the gloves. Not wanting to spend hard earned cash on a trial that might not work, I came up with a solution using an existing 3S LiPo and a chinese voltage regulator (£2) to provide a 5V output on a USB socket.
Result - I now have nice warm hands while sailing! The battery fits in an internal pocket of my jacket, and the wires to the gloves run down the inside of the sleeves.
Now I just need to find some heated socks 🤣