Anyone knows why a dry cell heats?

[mike915]

I know all the stuff of the configuration of the plates, that depending on how much voltage per gap you have you will produce more HHO or you will get more heat.

So if you have more voltage per gap you will get more heat but more HHO.

Well, what i want to know is if anyone knows the explanation for this why the cell produces heat.
Thanks a lot.

[redrat100]

This phenomenon is referred to as a "thermal runaway". It's the same reason deep cycle rechargeable batteries get hot when charging. Remember Ohm's Law? Given a constant voltage with decreasing resistance, current will increase. As our cells run, they will get warmer because we typically overdrive the voltage between plates to get more gas. This excess energy converts into heat. This heat lowers the resistance of the electrolyte which increases the current which turns into heat which lowers the resistance of the electrolyte which increases the current which turns into heat... and runs away until it boils over. Check it out with a volt meter and amp meter on your cell. As your cell gets hotter you will observe the voltage stay constant and watch the current slowly increase.

Hope that helps. Anyone, please correct or clarify.

[Macca]

So the voltage should be slowly decreased as a function of temperature?

[oicu812]

unfortunatly you still need around 2 volts per cell gap to produce a decent amount of gas. so that part of olms law stays the same in our case. most people controll heat isues with a pwm.

[koya1893]

not knowing what configuration you are running, I can only suggest running with -NNNNNN+. With this configuration you can run for 4-6 hours without overheating the cell.