Interesting idea. The grip heater I see on Canadian Tire uses power from the snowmobile and draws 3 amps at 12 volts. I think that's a lot more current than you can get from the battery setup you're talking about. But CT also shows battery powered heated gloves which might be a better source for the heating element.

Current draw increases exponentially with voltage. The 3A 12V snomobile grip heaters will only draw a fraction of that with 3.6V (3 rechargable AA batteries) or 4.8V (4 rechargable AA's).

I've done some work with those snomobile grip heating pads before. Using a 3 rechargable AA batteries, the pads heat to a point where they become uncomfortably warm to the touch. 3 rechargable AAs will last about 45 minutes. 4 rechargable AAs will last about 30 mins (higher voltage = higher current = lower battery life) and get 'hot' to the touch.

I think that running either 3 or 4 'C' sized batteries would give us sufficient heat. The larger 'C' sized batteries would last long enough to make it worth while.

Okay, I took the stock off of my 1077 today. There's plenty of room around the CO2 tank container to install snomobile grip heating pads. There's also plenty of room to install some thermostat switches.

I'm really not sure how much power would be required to keep the CO2 warm. What I could do is create a two stage circut with the following specs:

temp < 40C - apply 7.2v to the heating pads (3.24W)
40C < temp < 45C - apply 3.6v (0.81W)
45C > temp - cut power 0v (0.00W)

This should sucessfully maintain a temperature between 40C and 45C.

If someone were to fire serveral shots in a row (e.g. 36-48 shots in a row), then the CO2 would probably overpower the heating element and cool the gun. But by that time, the CO2 will have run out. By the time the shooter installs a fresh CO2, the gun would have had time to heat up again.

Ah screw it, that's too complicated. I'm just gonna apply full power until it hits 50C, then I'll shut it off.

michael >> temp < 40C -apply 7.2v to the heating pads (3.24W) 40C < temp < 45C - apply 3.6v (0.81W)

The heater I'm making uses 12V at 500mA to provide 6 watts to the heater(2 elements, 3 Watts each, one on either side of CO2 chamber). The 12V is handy, as you can plug it into your cigarette lighter in your vehical while traveling to the shooting location or hook up to an inexpensive wall transformer unit.

A 12V 1500mAh rechargeable battery is not unreasonable for someone to carry while away from a AC outlet or the 12V of their vehicle, car, motorcycle or snowmobile.

It is possible to apply higher wattage to my heaters in extremely cold temperatures as you may see in Canada. I don't generally recommend this as the heating elements get hot fast and there is potential for dangerous temperatures and pressures.

If a heated method was around everyone would know about it. There has been some limited usage of electric hunting socks being used over the gas tube.

The problem CO2 is a coolant so when you shot the gun the liquid CO2 changing into gas chills the gun. Heating will help but a significant amount of time is needed for whatever heating method being used to work and warm the gun back up.

Still, no need to give up on trying to find a suitable heating method.

I think an embedded micro-controlled circuit & heating element & sensors would be the way to go. Big problem will be supplying enough current to the heating elements and having a small package.

Art

 

I dont think that was neccessery.......

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Matt

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