Safe and Sound : Winter Survival Suit Post #4 (Carbon Fiber Tape)

The carbon fiber tape has arrived!! This update is showing how well the carbon fiber works as a heating element. Below are pictures of the carbon fiber. In them you can see that it is like fabric, it feels like silk. I am using 18650 3.7v 2600mAH batteries, I have purchased 8 of them hoping that will be enough for the entire suit to operate; they are rechargeable!!

Here is some interesting fact about carbon fiber:

It’s very soft, thin and flexible which enables it to be used in a wide range of textile applications where it may be subjected to continual movement and bending. The carbon fiber tape has similar characteristics to other heating elements available on the market however it is unique because of its flexibility and softness. In addition, another crucial factor with carbon fiber tape is that, unlike conventional heaters, it emits infrared heat that not only warms the top layer of the body but can also penetrate up to 5cm deep into the body making it far superior to other heating solutions currently on the market.

The maximum temperature is 400 degrees Celsius (752 degrees Fahrenheit). When over 400 degrees Celsius the carbon starts to oxidise into carbon dioxide and will start to evaporate. At 1200 degrees Celsius it'll last for a few hours but this decreases to just minutes when exceeding 1250 degrees Celsius. In a vacuum with no oxygen present it can generate more than 3000 degrees Celsius. When connecting the carbon tape, it is very important to ensure good contact between

the carbon fiber tape and the wires. The surface of the carbon tape will always be a reliable electrical conductor due to the surface oxidation turning into a gas and dispersing. This is unlike the surface of metals, for example copper, where because of oxidation the copper is coated with copper oxide which hinders a good electrical contact because copper oxide does not conduct electricity. Overtime this eventually results in contact failure which leads to power loss and potentially the overheating of contact points.

How to decide on what batteries to use for power. Under laboratory conditions there are batteries with and energy density of 200 (400)Wh/kg, but commercially available batteries are no more than 250 h/kg. Knowing the weight of your battery will give you a rough estimation of the maximum amount of energy it can supply. For example, an 18650 battery weighs about 50 grams so we can estimate that for a good quality, high capacity cell the battery could provide 12 watts of power. (0.25 x 50 = 12.5 watts). This theoretical calculation corresponds to the declared parameters of the Panasonic 3400 which is one of the most expense 18650 batteries commercially available. When selecting a battery, you should choose one that has a greater capacity than the amount of power you expect your heated clothing to use. For example, if your heated vest uses 30 watts it should be able to function for up to 1 hour from three 18650 batteries.

Carbon fiber tape can be washed in the washing machine, but for this application it’s not recommended due to the wiring.

Here are the specs for the tape I am using:

Carbon fiber tape