Help please with lithium battery project

Try an electric heating pad. See which setting works best. Figure the watts per square inch. However you have set yourself a difficult problem in terms of making something that works. You'll also need about 2 lb of battery at a guess.

Thanks for the quick reply. If you look at electric socks and gloves you will see that some of them use D size batteries, and not 2 pounds of them. I'm looking to heat a much smaller area than a hand or foot so I'm thinking that the lithium battery idea will work. Probably need two of them to get significant run time. ERS

You shouldn't assume you will save much weight or size - you may but don't count on it. Do you plan to use a camcorder LiON battery?

The socks and gloves relay heavily on external containment in closed volume. So their contibution is minute and most of them can be switched on and off. Take this in consideration.

HTH

Stanislaw

Hi Eric,

You want your wrists warm and your battery cool.

Keep your current limited to 1C. For a 1 Amp-Hour battery 1C equals 1 amp. Some new lithiums permit higher current, if they do they'll tell you.

What were you going to use for the heater element?

Jay

"Eric R Snow" wrote in message news: snipped-for-privacy@4ax.com...

Hello Eric,

Have you heard of a TEMS unit? I don't remember what the T stands for , but it is electric, doesn't produce heat, but it sets up a small (you adjust) pulsing current, using 2 electrodes you stick onto your skin with the pain area in between them. What it does, and it does work, I have one for my shoulder. It sets up a sort of a nerve block. Your brain starts to detect the pulse of electricity and after about 10 minutes starts sending out piles of endorphins to block it. It will also block the pain in the right area if the electrodes are placed right. It can be worn all day, or for an hour or so at a time. It runs on a NiCd 9V size rechargeable battery and is adjustable so you can adjust the amount of 'juice', so it doesn't hurt you, but just gets the brain to do its job. It is about the size of a small cellphone and can be kept in a shirt pocket with the wires running down your arms to where the electrodes are located. If you know anyone involved in Physical Therapy and/or pain management, they would be able to give you more details. For some people it works (myself included), for others, it may not work as well. It's worth looking into. I think it would be safer then thermal energy. It's certainly more energy efficient. I have multiple rotator cuff tears in my shoulder that are inoperable, and sometimes the pain is too much, so I will wear it for an hour or so, and the pain goes away after maybe 10-15 minutes. I was told I could wear it all day if necessary, but not at night.

hth, Joe

It's a TENS unit - Transcutaneous Electrical Nerve Stimulation (T.E.N.S.)

Does TENS work?

Greetings Jay, I don't know what kind of heating element would be appropriate. I'm thinking nichrome wire out of an old toaster might work. Using your answer about battery drain I should be able to figure something out. Cheers, eric

Greetings Joe, I used a TENS unit for about a year while nerves were growing back. It was remarkably effective. However, it just didn't work on the joint pain. My doctor explained that this is because bone pain, especially from bone on bone joints, is especially hard to control. If my wrists were fused this pain would probably go away. However, I want to keep my wrists somewhat flexible as long as possible. ERS

I will. Thanks. ERS

Hello Homer,

Thanks for the correction, and for the link. I visited it, and, like they say, it would be difficult to judge the efficacy of the treatment. Pain is a very subjective thing. In my case, I have multiple rotator cuff tears in my right shoulder. Even sitting at the computer and trying to move the mouse was painful. When the VA (my only health care provider) offered me a trial, I jumped at it. The physical therapist also explained to me that in some people it works, and in others it does not work as well, and in still others it does not work at all. I believe I spelled out these caveats to the OP. I was fortunate that the VA was willing to let me try it for a week before ordering one for me. But I saw such a difference in the pain levels that I just thought I would mention it to the OP. I have a pretty high tolerance to pain too, so that may have something to do with it. I didn't see anything in the studies that mentioned patients with a 'high' pain tolerance. My pain is chronic, so my other options included narcotics, ie percocet, vicadin, etc. which were unacceptable to me because I would be sleeping all day.

Anyway, thanks again for the correction, and for reiterating the possible benefits or not concerning TENS.

If the OP can find someone who would give him a trial period and see how it worked first, then that would be so much the better.

Joe

I'd hack into an electric blanket. The element is flexible, and already designed to be used on humans. An ordinary blanket runs on

120V, so I'd think 1/10 of the element would reach the same temp. at 12V, and half that at 6V, and so on.

I have no idea how they connect to it, but it's probably easy to crack open that little plastic knobby thingie and find out.

Good Luck! Rich

I'm familiar with the wires from electric blankets and motorcycle suits. They use a thin copper ribbon coiled around a bundle of fiberglass like core. The connections are done by crimping and sealed with heat shrink tubing. Get a length that equals about several ohms and it should put out the right heat for a lithium battery.

If you want to heat your wrist, I'd say a couple of watts ought to do the job well if you are making something like one of those wristbands. Should be comfortable and look quite sporty too. Sounds like a fun worthwhile project!

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-=Duane
http://www.dattaway.org