Thursday, September 8, 2016

New project

Back in the saddle again...

As if I needed any more projects I've started work on something new. I saw some videos on YouTube of people using peltier devices to charge cell phones. This got me thinking that a Coleman lantern makes a ton of extra heat so why not put that heat to good use.

This is a peltier device, if you put electricity across the two wires it'll make a cold side and a hot side, so it transfers heat from one side to the other. If you work it the other way around, that is apply heat to one side and cool the other it will produce electricity.

Which leads us to:

A Coleman 228E with a peltier strapped to the vent. The outer vent edge shown gets to about 150F. In testing the outside of the heatsink was getting to around 100F. With that temperature difference (delta) the peltier was making around 1/4 volt. Thats proof of concept but not really enough power to do anything...

Experiment two got us more heat, the top of the vent is more like 250F, the ends of the heatsink were now reading more like 120F and you can see in the picture we got around .85v. This is a semi-useful result, I could run several peltiers in series to get a useful voltage but its still disappointingly low. I sprinkled some water on the heatsink and got 1.9v which is a very good result.

This tells me the issue is insufficient temperature delta, the hot side is plenty hot but the cold side isn't cold enough. The heatsink I was using is really small, I've got another much larger one from an old computer case to try next but before I go there I need to make a better system for mounting the peltier and heatsink. Lantern vents are rounded at the top, I really need a flat surface 40mm wide to mount on. I'll work on that next...

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