Personally for worst case energy consumption to battery size scenarios I would go with a Lithium, Nicad or NiMH based battery system made of a bunch of single cells made up in strings or groups to get the your necessary energy storage capacity.

Do you think his coworker's will hang a nickname on him of "Smokey" or "Flash".
Or, maybe "Galaxy" or "Dreamliner"

 

The battery pack I plan on using is 12v 20Ah Lithium-ion Li-ion is smaller then a VHS case. There is an on/off switch on it and it looks like a laptop jack for the output power. Just trying to figure out what type of switch to use so I can regulate the output voltage

 

The battery pack I plan on using is 12v 20Ah Lithium-ion Li-ion is smaller then a VHS case. There is an on/off switch on it and it looks like a laptop jack for the output power. Just trying to figure out what type of switch to use so I can regulate the output voltage

Turn it on until you smell ham or bacon (smell varies depending where the heaters are placed).

 

Don't worry about regulating the voltage. Just regulate the time that the voltage is on. Pulse Width Modulation.
Remember....from school.

 

I'm either sitting at a laptop or holding a test switch outside. I don't constantly move around enough to take advantage of thermal clothing.

As someone who was born and raised in a cold climate area I have call BS on that.

There are always ways to dress for extreme cold and little movement. At worst case spend $200 - $400 on a two piece full body 4 - 6 mil scuba suit set with booties and hood and wear that under your normal proper winter gear with a set of 600 - 1000 gram thinsulate boots that fit over the scuba booties. -35F with wind and you will be sweating it out sitting still.

When someone says it's too cold to work outside it's because they are not willing to either listen to those who do know how to dress for the weather or they are too cheap to buy the right clothing for it.

 

There are always ways to dress for extreme cold and little movement. At worst case spend $200 - $400 on a two piece full body 4 - 6 mil scuba suit set with booties and hood and wear that under your normal proper winter gear with a set of 600 - 1000 gram thinsulate boots that fit over the scuba booties. -35F with wind and you will be sweating it out sitting still.

I daresay! -- 'Tho A 'bargain-basement' snowmobile suit will do the trick and at a fraction of the price...

But to your central point -- Yes! I too heard a rumor to the effect that humans are homeotherms -- Hence, so long as temps remain well above the BP of O2 (which being likewise > than the BP of N2) - adequate insulation is all that's required!

When someone says it's too cold to work outside it's because they are not willing to either listen to those who do know how to dress for the weather or they are too cheap to buy the right clothing for it.

I must admit to having little to no patience with people who don't appreciate low temps! -- Seriously 'tho, as I see it, 'cold air' is one of the very few 'natural kindnesses' shown our species - in a world where well-neigh everything in the way of comfort and contentment 'comes high'...

Best regards
HP

 

Don't worry about regulating the voltage. Just regulate the time that the voltage is on. Pulse Width Modulation.
Remember....from school.

Hmm I understand what you mean, but I'm curious as to why that is a better option then just regulating the voltage. So I can just use a PWM controller to adjust the pulse width modulation. Will his be able to give me a full range of heat? Like another person posted ill never need to go to max head 70 Celsius unless I want to smell bacon or ham burning.

 

Because it increases your battery life. If you draw current from battery only half the time.................the battery will last twice as long.

 

I daresay! -- 'Tho A 'bargain-basement' snowmobile suit will do the trick and at a fraction of the price...

I have not seen any snowmobile suits that have the same 'second skin' fit that a basic scuba suit has that will fit under another outer layer of clothing like a set of work coveralls.

I have however seen people spend a small fortune on a high end supposedly super warm snowmobile suit only to look like a gaudy christmas tree ornament and still freeze their butt off if they weren't moving around.

 

So if I use a 10Ah battery pack for 2-20 watt heat pads then I need a 12V 10A+ PWM controller?

 

I have not seen any snowmobile suits that have the same 'second skin' fit that a basic scuba suit has

No argument with that!

I have however seen people spend a small fortune on a high end supposedly super warm snowmobile suit only to look like a gaudy christmas tree ornament and still freeze their butt off if they weren't moving around.

IMNSHO Some people 'chill' too easily Perhaps they should relocate to the South and call it good

Best regards
HP

 

So if I use a 10Ah battery pack for 2-20 watt heat pads then I need a 12V 10A+ PWM controller?

However you choose to proceed, please be cautious! Thermal injury can be insidious!

Sincerely
HP

 

The current rating of the PWM has nothing to do with the Capacity rating of the battery. Connect the pads in parallel and connect to a 12 v source. Now measure the current. That is your maximum current. Let's say that current is 3.33 amps. We would want to rate the PWM current to at least 50% greater than the max. So a PWM with a 5 amp rating would suffice.

If you are really trying to stay warm............you can not beat the proper clothing.

It's a business expense. Buy the best and depreciate.

 

I must admit to having little to no patience with people who don't appreciate low temps!

HP I say you might look on that differently if outdoors was your workplace instead of playground!

So to the topic

Making Heated pants/shirt liner using 12v heating pads and fan controller.

Dan Pizano I say heated clothing is a bad idea cuz it's like HP says in post 32 you can basically cook your tissues w/o knowing it! It happens a lot to ppl who sleep under heat lamps and like that! They discover 2'nd and 3'rd degree burns when they wake up! So don't just assume discomfort will warn you if tissue is being damaged cuz it doesn't always wrk that way! So just 1'st and so called mild 2'nd degree burn over an area can release enough myoglobin and amines into bloodstream to cause kidney problems so plz just dress warmly and leave it at that!

 

HP I say you might look on that differently if outdoors was your workplace instead of playground!

Well... One's 'workplace' is difficult to love under any conditions!

So just 1'st and so called mild 2'nd degree burn over an area can release enough myoglobin and amines into bloodstream to cause kidney problems

While I assert that rhabdomyolysis (and, hence, myoglobinemia) is far less of an issue with superficial --as opposed to deep and, especially, electrical-- burns/injuries - your points are spot on! 'Wearable' heaters (including, IMNSHO 'electric blankets') represent utterly unnecessary hazards!... And yes! Severe - even fatal - injury may occur with little discomfort!

Sincerely
HP

 

don't just assume discomfort will warn you if tissue is being damaged

I think this nerve system was designed badly. You might not know you're being burned, you don't know the cartilage in your knee is about to hole through, but the winter static electricity has me cussing every time I get up out of a chair and brush past an interior wall. When I die, I'm gonna have a chat with Dog about this.

 

Due to my arteriosclerosis, I have to use an electric blanket now. One can over do it with too many folds or too high of a setting.

On second thought, maybe the bacon grease was a bad idea.

 

Due to my arteriosclerosis, I have to use an electric blanket now. One can over do it with too many folds or too high of a setting.

On second thought, maybe the bacon grease was a bad idea.

Ya think?

@BR-549 Seriously! - Please do not interpret any of my (nor, for that matter, Aleph's) comments as medical advice! -- Tis but well considered opinion! - Nothing more!

Most sincerely
HP

 

I have to use an electric blanket now

I have a heating pad on a dimmer. I run it at 30% of the knob rotation. That's about 7 or 8 watts in most of a square foot, and it works for me (in Florida). That small amount of heat relieves muscle spasms and makes a lot of difference keeping me warm while I'm sleeping. That's why I'm recommending two heaters in series for an output of 10 watts for this heated jacket application. Anything over 10 watts per square foot will cause a hot spot on a human.

 

Please do not interpret any of my (nor, for that matter, Aleph's) comments as medical advice!

You sound like a TV commercial I saw:
"Spokesperson is not a doctor (or a lawyer). Please pay highly inflated prices for retail medical/legal advice."

I reserve the right to reach my own conclusions. I just can't sue anybody for my own thought processes.