Hello all,
first time poster here. I have recently discovered the joys of stringing up my hammock while out camping. At first all my friends thought I was nuts, but the tide changed once they say how comfortable I was all night
A few weeks ago I took my cordless down to a favorite spot we had been going to for years, but had always slept on the ground. With a few anchor points installed into the rock face (dynabolts) we had room for up to four hammocks. All of us stayed dry inside this little riverside cave, despite a decent down pour in the night. I did however get a slight chill on my back, partly due to insufficient windbreaking. Ive learnt alot just trawling through these forums on how I can remedy this, but seeing just how COLD some of the temperatures are that users battle I was inspired to come up with something that could help.
I did a quick search and couldnt seem to see anyone that had posted this idea before, though Im sure it has been thought of countless times. What I propose is a portable, efficient heated blanket (or item of clothing?) powered by a small DC rechargeable source. Given the power consumption for electrical heating is generally very high the challenge will be:
Efficient and quick heating of the area safely.
Portability, repeated cycles (IE, not damaging the battery) and run time.
User functions, like the ability to regulate heat/amperage draw.
Some of you may laugh at this idea, and I will admit I did at first, but after a quick stroll through the web I discovered that this might actually be possible.
I already have a reasonable knowledge of the electronics involved, being a hobbyist in my spare time as seen on my channel http://www.youtube.com/user/shannrenn. All of my electrical hobbies involve DC power, batteries are my life here I recently built a custom high power torch from a gutted dorcy, I call her the "pocket sun" powered by a single lithium battery, but thats for another thread perhaps.
So first up I stumbled across this page. http://www.hastie.org.uk/heatedjacket.html
Being a motorcyclist in my past I can sure appreciate the need for a heated jacket/pants/golves on a cold night. But a search of commercial products saw me forking out over $150 for a basic model. Come on people, its a bit of nichrome wire sewn into the lining of a jacket......
Some other possibilities included DC heated blankets (for use in the car usually) and even heated pet mats! The heated pet mats are specialty items and are thus almost as expensive as the heated clothing, but the DC blankets are more on par, some as cheap as $20. All of them vary from 12v @ 1 amp (12 watts) to 12v @ 5 amps plus (60 watts). Not too sure how warm the 12 watt matt gets, but if its useable, I could build a lithium power pack with three/four D cells that would last for approx 7 hours (3.7v 7amp/h D cells, about the size of a large maglite). The other thing is this doesnt have to run all night. You could warm it up to start with and then not even need it for the rest of the night. It could be helpful in an emergency too I guess.
I would probably look at installing a PWM (pulse width modulation) controller or variac that would allow the duty cycle or resistance to be varied, thus controlling the input current. Ive learnt some very clever unconventional techniques that may also allow for energy recovery/recycle power back to the source which could boost efficiency even higher. Of course there would be a fuse installed as well for safety.
My wife is a master seamstress, which will surely make things easier, as I dont have a clue about sewing! I have already prepped her on the basics, and she says it will be easy to sew, especially if it just a flat mat to heat your back and bum. This could even end up being incorporated into a hammock if it worked well. Imagine being wrapped in that warm cocoon!
It might just give the edge to those looking to battle the freezing temperatures in the snow, or it could just end up being a dud But I will have alot of fun on the way, I have plenty of spare wire so why not.
One things for sure, my missus will only come hammocking with me in winter if it works, cant get her outside other wise, might need to make a fully heated yeti suit for her.....
Thoughts and comments appreciated. Sorry about the lengthy post...
Regards
Ren
(PS second picture is the view from my hammock, hanging from the rock face )
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