will this work? thermoelectric phone charger
 

Hi everybody,
I'm putting together what I hope will charge my n900 from a camp fire. I ordered this thermoelectric generator that puts out about 1 volt, and a lv boost to bring it up to 5 volts.
My plan is just to wire it up to a usb plug to connect to my phone. since I know nothing of electrical engineering, I was hoping someone would tell me if I'm missing anything. thanks

Re: will this work? thermoelectric phone charger
 

The short answer is no.

Your first link is to a device that gets cold on one side and hot on the other when you pass an electric current through it. It will make some electricity when you heat one side *_AND_* cool the other.
Where do you see that you get 1 volt when you do that? Also, how much current?

Your second link is to a device that requires 3 volts input to produce 5 volts output. 1 volt will not do it.

After you fix all that, it will take hours to charge your n900 a few percent.

You will have better luck using a golf cart motor to push a full cement truck.

Re: will this work? thermoelectric phone charger
 

I think a thermoelectric cooler is the same as a thermoelectric generator. When I heat a griddle to 300 degrees and put it on with a heasink on the other side, my multimeter shows as high as 1.7 volts. As both sides heat up the voltage drops.
I'm not sure how to check the current, but probably not much.

The lvboost will output 3.3v - 5v, but the input is listed as 0.5v - 5v.

Agreed it won't do much. My hope is it will give me enough power to check my gps quick if I get lost while I'm out backpacking.
thanks for the reply.

Re: will this work? thermoelectric phone charger
 

Your better bet is to buy a solar charger...or a second battery.

Unless you want this as a little project, it might not really be feasible.

Re: will this work? thermoelectric phone charger
 

Yes, that is true.

Your multimeter has a high resistance, and does not put much load on your thermoelectric device. As soon as you attach your boost device, the voltage produced by your thermoelectric device will plummet. Also, as you noticed, the power produced will quickly drop unless you keep the cool side cooled.

Your second link says:
OK, the 500ma @ 3v gives you some margin. At lower input voltages, the output can be maitained for a while with reduced current. But, even 500ma is not much for charging an n900. People have reported n900s slowly losing charge while connected to a computer by USB.

You are not only not going to get 3V out of your thermoelectric device, you are not going to get the 1.7 V that you get with an open circuit. You are certainly not going to boost half a volt to 5 V.

Your n900 will not charge without 5V in.

As mentioned above, you would be better off with a solar panel, and even better off with an extra n900 battery or an external battery pack, maybe with a booster.

Re: will this work? thermoelectric phone charger
 

Solar panel with intgrated Li-Ion battery. then one could try feed extra power from the TEG+lvboost in through the same path as the panel...

Re: will this work? thermoelectric phone charger
 

That sounds like a good idea. It's probably safer to charge a battery seperated from the phone.

I'm getting 1.3 amps at 1.5 volts with 300 degrees. According to the lvboost.pdf that should put out 300 ma at 5 volts. I hope to get it put together later this week.

Re: will this work? thermoelectric phone charger
 

Get one of these https://powertraveller.com/iwantsome...nkey-explorer/

It's what I used when I went travelling, worked amazingly well, you strap the solar panel to your backpack and charge while you walk, you can either charge the separate blue battery or directly charge your phone.

Re: will this work? thermoelectric phone charger
 

Another reason for the reuse of solarpanel+battery -charger devices is that they're designed to charge their internal batteries from low current source, and have built in booster for boosting the battery voltage to 5V..

It's probably not entirely reliable to get N900 to charge from 200-300mA with bme, or atleast I've found it a bit unreliable with the default software. So the external storage battery+panel+teg would also serve to discharge the harnesses energy at a rate N900 is happier with.

Those are some impressive figures for your teg though.. How do you maintain a 300 degree temperature differential I wonder? :)

Re: will this work? thermoelectric phone charger
 

The powermonkey looks nice but a bit pricey.

I've been testing with my griddle set to 300 degrees so it's only about a 200 degree difference. I set a cup of water on the other side.