Question Sometimes I have to sleep outside. I am going to make a portable heater that has fans plugged into a Rasberry Pi. Do any of you have some tips?

[David_24]

I wasnt able to find a portable space heater that runs off a battery that i could buy in a brick and mortar store so i'm just going to make my own someday.
My first one will be a rasberry pi thats not a pico or a zero. A full Rasberry pi.

I want to be able to have the rasberry pi to sometimes get charged off of usb devices I'll plug into it once and a while.. So instead of it charging the devices the devices charge it. Im not sure how i'd program it to be like that or make it do that some other way.
Can you recommend some batteries I could hook the rasberry pi to. Also do you know websites where I could buy heaters from.
I'm not sure what i'll use for the case for the thing.

How many fans can i plug into a raspberry pi anyway?

 

[USAFRet]

Something to run the fans is trivial. A simple thermostat to turn it off and on would work.

Your main problem is enough wattage to actually produce usable heat.

 

[OldSurferDude]

@David_24,

@USAFRet is right. You need to concern yourself with the energy source first. Let's say you need to be warmed for 8 hours. Let's take a typical space heater which 1.5kW. You will need batteries of 12kWh, but you don't want to run the batteries down to zero, only 20% so 15kWh. A Tesla power wall has a capacity of 13.5kWh and costs about $12,000. Now these are a little spendy, and I'm pretty sure you could get the cost down to $7k if you competent with the electronics that could do it.

The batteries and charge controller are going to weigh about 250# (120kg)

You'd need to charge these batteries. How are you going to do that? A long extension cord (10AWG 100') that is capable of charging the batteries is as cheap as $120, but then, why not just plug the heater into that? I suppose you won't be near an electrical outlet, so you'll have to put the batteries, etc. on a Gorrilla Cart ($150)

It would appear that batteries would not be particularly practical.

A propane heater? $40. You'll have to get the tank filled every three days, so ~$7/night ($1300 for 180 nights)... cheaper than a motel? Of course you're damaging the ecosphere by using fossil fuels. You might need 2 or 3?

I'd suggest a better sleeping bag (REI $400). I slept in one for two winters. You have to wash it at least every two weeks.

 

[David_24]

I think that the portable space heater I'd put together out of different stuff would be good to have even if it wouldn't be as powerful as what would be in your opinion a "typical space heater". Even if it doesn't heat long or heat well I would still want to have it.
I sometimes have no other option but to sleep outside so I do actually want to do this even if what I would put together from different things is bulky to bring around. I'm thinking of purchasing a push cart of some sort. It gets cold in Canada.

 

[USAFRet]

I think that the portable space heater I'd put together out of different stuff would be good to have even if it wouldn't be as powerful as what would be in your opinion a "typical space heater". Even if it doesn't heat long or heat well I would still want to have it.
I sometimes have no other option but to sleep outside so I do actually want to do this even if what I would put together from different things is bulky to bring around. I'm thinking of purchasing a push cart of some sort. It gets cold in Canada.

Please show us your heater wattage and battery capacity calcs.
Even just 1/2 a "typical space heater".

 

[COLGeek]

I think that the portable space heater I'd put together out of different stuff would be good to have even if it wouldn't be as powerful as what would be in your opinion a "typical space heater". Even if it doesn't heat long or heat well I would still want to have it.
I sometimes have no other option but to sleep outside so I do actually want to do this even if what I would put together from different things is bulky to bring around. I'm thinking of purchasing a push cart of some sort. It gets cold in Canada.

When sleeping outside, are you in a tent? Warming a tent is a far different scenario than you being in the open.

I have used a candle to warm the inside of a snow shelter or even nothing at all but body heat and a proper sleeping bag/bedding.

Please describe your environment a bit. That may help with options.

 

[OldSurferDude]

Search for something like "going off grid" There you will find a plethora of information about batteries and charge controllers.

I highly recommend the gorrilla cart. I bought one to move block around my yard, about 200t ! a typical load was about 250kgs which one person, with difficulty, could move on level ground. I still have the cart. (be sure to use soapy water to lubricate the rim and bead when repairing a flat tire)

Still, your best investment would be a good sleeping bag and tent.

Good luck

OSD

 

[Eximo]

Small tea candles are apparently around 32W.

A portable power bank with around 8 hours at that output is about $200, A full AC inverter portable power pack even. It has a 60W USB-C output.

Type-C adapter and a $5 1 Ohm 50W resistor would do. Though convincing the USB-C port to provide the power would take some doing.

Have you considered a laptop running Folding@Home, apparently you can do offline work, or you could tether it to a phone to upload results.

 

[OldSurferDude]

The idea of a laptop is brilliant! The challenge then is to find batteries that will last for hours! Lithium batteries, while having a high upfront cost will last longer than lead-acid batteries of the same kWh capacity. Here's an example next what is needed is a charge controller to charge it and a 12V adapter for the laptop.

OSD

 

[OldSurferDude]

problem is, it will take 33 hours to charge the battery OSD, But, if you had three batteries, two could be charging while the one is being used. Again, we're getting into some money here.

OSD

 

[Eximo]

Laptop plus a few USB battery banks will do, or just one large one.

Heck, battery bank/inverter and an incandescent light bulb would work pretty well too. Could even find a heat lamp bulb for less light and more heat output.

 

[USAFRet]

And we still have little or no idea of the environment involved.
Tent, out in the open, etc, etc....

While a laptop can provide 'heat', I would think the outside environment is not the place to really use a laptop. Water, dirt, etc.
In addition to $$$$.

 

[David_24]

Well I didn't want to worry you with the truth but It gets pretty cold and A lot of places are not tent friendly. So I was just going to have it running under some blankets with me but with a lot of fans going and i'd have some of the blankets propped up with some stuff. I feel like I would wake up if the thing caught fire. Perhaps I could have a smoke detector hooked into the rasberry pi to trigger a loud alarm hooked to the rasberry pi if the smoke alarm got triggered and also I could have the settings on the rasberry pi be such that it would turn off if it overheats too much. I also will buy a tent someday. So I might make a larger version for that and also use the smaller one I had for being under the blankets with me to heat inside the tent without being under blankets when I'm in a tent. I'm really thinking of making more than 2 of these things eventually. I want to eventually leave behind some tent sites in some different places in different woods that I could go back to when I want to. If it's off the trail enough or in woods that have no trail I don't think anyone would should mind me doing that.

 

[COLGeek]

I have to tell you, not only do I see costs for a solution going up, but the weight and complexity as well.

David_24, what are you not telling us about the situation here?

At first, I was thinking of someone trekking/hiking, in need of solar panels to charge items and some means to warm a portable shelter (tent). But, that doesn't seem to be the case.

 

[USAFRet]

Possibly a pair or two of these:
https://www.amazon.com/Rechargeable-Electric-Portable-Raynauds-Outdoors/dp/B0CFQYP7GX


Or a 40-pack of this:
https://www.amazon.com/HotHands-Body-Hand-Super-Warmers/dp/B0007ZF4Q8

 

[David_24]

I quiet often live in a shelter. I might have to go without having a bed indoors for weeks on end during the winter. I might have to sleep outside in inner city Toronto. Calling central intake when I don't get to stay in a shelter often takes me trying to call them every other day or so for weeks before I get a spot.

 

[gggplaya]

Honestly the power requirements for heating a space like a tent, especially non-insulated, are huge and not really feasible. You can get battery powered units that use small 1 gal propane tanks, but you'll be swapping tanks 2-3 times a night.

Your best bet is to get a rechargeable heated sleeping bag. I would try to get one where you can swap batteries and buy a few extra batteries.

You can order them on Amazon and have it delivered to an Amazon Counter or Amazon Locker in Toronto if you don't have a delivery address. Amazon packages can be returned to a Whole Foods Grocery story if it doesn't work out for you.