Hello All,

I'm working on a show that we are shooting in the Alaskan wilderness. I am about to send 2 guys out on a 4 day expedition, and was wondering on some tips to keep batteries full and warm over the course of these 4 days. We will be shooting with 2 EX3's and have about 50 BP-U60's and 20 BP-U30's. We will have no electricity to charge over these days, and our area has been experiencing -35 F temperatures.

I'm putting together a Styrofoam cooler to keep our batteries in, and have heard about using a hot potato wrapped in tin foil in the cooler to keep the temp up. This way they can reheat the potato at night and continue using them over the 4 days. Our operators will be wearing batteries in their coats when they can.

Any other options or recommendations for us? Any suggestions are welcome.

Thanks!

How about taking a couple of cases of those chemical handwarmers? Throw a few in the cooler. They contain pretty benign stuff like sawdust, iron filings, and charcoal IIRC.

We are going to bring a bunch, but they haven't been working out great for us. Also we have to keep our weight down because we are traveling by dog sled and two snow machines. Ideally I'd love to have some reusable heat source, or other alternative.

we are traveling by dog sled and two snow machines.

Do the snowmobiles have batteries?

Adding 12v accessory plug - Snowmobile Forum: Your #1 Snowmobile Forum (http://www.snowmobileforum.com/ski-doo-snowmobiles/40120-adding-12v-accessory-plug.html)

We are going to bring a bunch, but they haven't been working out great for us. Also we have to keep our weight down because we are traveling by dog sled and two snow machines. Ideally I'd love to have some reusable heat source, or other alternative.

There is a system used to keep airplane engines warm in the bush that might work. Pre heating the cub... Alaskan style [Archive] - SuperCub.Org (http://www.supercub.org/forum/archive/index.php/t-31814.html)

I've used the Sony BP-U batteries at similar temperatures and the drop off in performance was about 40 to 50% of capacity lost. If the batteries are warmed prior to use by keeping them inside a jacket for an hour first, then the loss of capacity will be minimal. I use the chemical hand warmers to keep stuff warm if needed, while the hand warmers rarely get hot, the heat they do produce is enough to keep away the worst effects of the cold. I would get a nice thick sock that you can stuff with hand warmers and batteries. At those temperatures your going to have to be very careful with the LCD panels. These freeze and crack at somewhere between -30f and -40f, certainly below -40f if unheated or un protected they will self destruct.