Battery Pack for Warm Hands... Ski Glove

I have always found for heating purposes in general, batteries of any kind, just don't last long enough or give out enough heat for me, and I am always disappointed.

I got a few of these lighter fluid hand warmers a few years ago, and I find they work great and last a long time, but you can't fit them in a glove, but you can stick them in a pocket. You can also get ones that start with the press of a button so you don't need to light them.

I know hunters often just take two 9v batteries and stick them together, although that seems expensive and is just asking for a leaking battery in your pocket.

I've used these types of dry chemical hand warmers (link below) and have been satisfied with the warming they provide. You can get them small enough to fit into your gloves and boots. Unless you do A LOT of skiing and are willing to put up with the hassle of recharging the batteries, the cost of the re-chargers and extra sets of batteries might not be worth it.

http://www.amazon.com/HeatMax-Hot-Hands-Handwarmer-pairs/dp/B0007ZF4OA/ref=sr_1_1?ie=UTF8&s=sporting-goods&qid=1289937147&sr=8-1

Here's some good tech info on batteries that I've found helpful in the past. Just follow the link to tech resources.

You may want to check out Li-po batteries. They have high charging and discharging rate....

I use LiPo batteries for my model aircraft and my wife has heated gloves for the motorcycle. Certainly the required battery would be surprisingly light, but I do have reservations about combining the two technologies for skiing. I suggest that the chance of getting the circuit wet is higher than even on a motorcycle, and that the batteries may be working at an extreme of their temperature range.

http://www.rctoys.com/pr/2006/10/20/safe-use-document-thunder-power-lithium-polymer-batteries/

<< and that the batteries may be working at an extreme of their temperature range.>>

A really valid point at extreme temps people were having it on their bidies to warm batteries to function.

But it may be possible that new batteries may be active at extreme low temps.

Here is a pack that I think fits the bill....

http://www.batteryspace.com/nimhbatterypack132v4500mahsmartfastcharger18aforbikelightstrailtechplug.aspx

It will be worn underneath the shell, so temperature will not be too extream. I can add to / modify the holder to be under arm - over neck style so the pack rests on the side. @ 1 3/4 lb it's pretty heavy...

Tri-level controller

http://cozywinters.com/shop/wg-tri-controller.html

I'd look into the 12 volt lithium batteries for power tools. I have a Milwaukee right-angle drill that is remarkably powerful for its size, and the battery pack is about half the size and weight that you'd expect. The charger is light and sophisticated, and the batteries do not self-discharge quickly: last time I charged the pack was 2 months ago, and the tool still indicates that the batteries are fully charged. Unfortunately, if you need three hours, you'd need two of these packs, which are 1.4 Ah each. (I wonder if you could make a PWM controller that would provide just 4 watts -- maybe with well insulated gloves that would be enough?)

Second best would be AA NiMH "hybrid" batteries. They also have a low self-discharge rate, and come in 2800 mAH sizes (you'd need 10, in series). (The large sizes [D, for example] often offer no advantage in capacity -- some are just AAs in a large case.)

A Milwaukee pack could be easily slipped into an inner parka pocket. If the pack were flatter, that would be better (for fewer bruises in falls) but in other respects, this would be a simple solution. The same cells are used in Dewalt tools, and for a long time, electric car enthusiasts have taken apart the Dewalt packs to use the cells -- which have otherwise been unavailable on the market. (The Tesla roadster battery pack uses thousands of these small cells, crazy as that may seem.) A123 is the vendor to Dewalt.