I’ve been building, researching, and selling various hho cell designs for quite awhile now, and these are some of my thoughts/ findings/research/etc, for whatever they are worth.

Salt is an absolute no-no, as is anything else that contains chlorine atoms/ions. The chlorine will absolutely rip into your stainless steel electrodes (and most others as well) and corrode the cell into a very early grave. If you are running cells based on a full strength baking soda solution/electrolyte, you are good down to maybe 20 degrees F (I had one freeze and crack last week at 15degrees). If you are running full strength sodium hydroxide, you should be good down to quite a bit colder than that. Full strength sulfuric acid electrolytes can tolerate down to zero and lower. Denatured alcohol will eventually vaporize out and cause failure when you least expect it. And if you are using one of the cells out there that uses straight tap water, too bad, so sad. See below for my comments about heaters.

The real issue though is generally not with the cells themselves (at least the electrolyte catalyst ones); it’s with the bubblers and water based back-flash arrestors. They are usually straight tapwater based, and if they freeze up, they’ll block the hydrogen flow and pressurize the cells, leading to burst hydrogen cells in the best scenario, or potentially catastrophic hydrogen explosions and fire under your hood at worst. Fortunately, straight antifreeze in the bubbler is fine, as long as you have a variety of cell that does not pull water from the bubbler after shutoff and cooldown when the solution inside the cell cools and contracts and sucks water back over from the bubbler (many designs out there do this- some of mine do, some don’t). If you have a suck back variety cell, you can just fill your bubbler with the same strength electrolyte in your main cell to keep it from freezing (this can become a problem though, in that this can cause the electrolyte in the actual cell to slowly get more concentrated, thus drawing more amperage, producing more hydrogen, and running a lot hotter – so there’s issues with this idea too, especially if you are not running full strength electrolyte to start with which CAN’T get more concentrated – in this case the extra electolyte will just precipitate out of the solution as crystals in the bottom of the cell). Yes, there’s a lot to know about keeping these things running in top form

Which leads us to heaters. The easiest thing to do is simply go buy heat tape/cord for plumbing pipes, the variety that turns on automatically when the temp gets low enough (built in thermostat). Just make sure the cord’s rated temperature isn’t higher than whatever temp your cell already runs at -many cells run in the neighborhood of 180+ degrees (especially the baking soda ones). Then directly wrap your cells with the cord/tape. Then just make sure to plug in the heater cord overnight and/or every time you park anywhere for more than a few minutes.

If your cell is not one of the high temperature varieties, insulation can a good idea in the wintertime too, just to keep the cell warm while operating, and to likewise hold the cell’s heat in longer after shutdown (warm/hot cells generally/usually produce more hydrogen than cold ones). Don’t use it in non-freezing weather though – overheating could become a real issue. Check with your cell’s manufacturer about insulation just to be on the safe side.

So the short answer to a big question is…. there are different answers to different cell designs. Sorry… The only surefire answer to all of them is plumbers heat tape/cord that you plug in whenever the engine is not running.

This IS an issue for people all over the country, and I do address it in the kits I sell. I HAVE to! (I live in the mountains myself). Expect to see more and more manufacturers adressing it soon.

That’s my 2 cents worth. Hope it helps someone…