Solar vent motor replacement

Excellent! Thanks for posting Gary. I wish I'd seen this a few months ago. Mine stopped working so I bought a new Li-Ion battery. It didn't work so I concluded it was either the motor or the panel or wiring. I couldn't find parts so bought a whole new one (same deck cutout fortunately). A new motor would probably have done the job. Need to search more thoroughly next time! My rationalisation now is that solar panel technology is improving fast, so the unit I just bought is possibly better anyway. And it's a quieter motor. Anybody need an unused battery for free?

I used the cheaper plastic solar vents with no battery, and they died after a year, from steam and gunk rising from my cooking. (it was right above the stove).
A cheaper alternative is to use a computer fan, 12 volt easiest, and wire it in (tap it into) the wires between the solar panel and the regulator, so that it will only work in daytime. Wattages are typically 2 to 3 Watts, i.e. nothing. A simple plastic grille over the fan will suffice, especially on a vertical surface such as near the cockpit or in the hatch panels.

I have the same set up as Phil but a single fan and runs 24/7 except for when im on the boat which is not to often, been going for nearly 2 years, sucks out so much more air then those solar ones and 90% cheaper
Highly recommend it

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southace said..
I would have thought those computer fans only cool computers and fringes. Not sure they would circulate much air in a yacht. Would be interesting to do the tests.

The nice varnished hatch photos are not mine, but copied from somewhere online years ago. I have made the same set-up in the previous yacht, and in my steel garden shed, and I hear and feel them exhausting hot air each time I pass by. Reliable. After Lockdown, I will need to install one in my yacht.

By way of comparison, the cheaper white marine solar vent, www.whitworths.com.au/plastic-solar-exhaust-vent here extracts 680 cubic feet per hour, or 11.3 cu.ft. per minute. Computer fans are built to run for years, and some models are much quieter than others, and there are variations in voltage and diameter from 40mm, 50mm, 80mm, 90mm and 120mm. Most of them fall into the price bracket of $18 to $25.
A quiet 90mm fan here: www.jaycar.com.au/90mm-silent-hydrodynamic-bearing-case-fan/p/YX2572 (90mm, 12 volts, silent operation, $25, about 2 Watts per fan) here claims three times the air extraction, i.e. 31.3 cub.ft/min or 0.89 cubic metres/minute. You could always use 2 of these, with any ducting to push/pull air into the forecabin and in the stern of the boat too.
This fan: www.jaycar.com.au/90mm-12v-dc-2-wire-fan/p/YX2521 does 1.67 cubic metres a minute for almost 4 Watts, $20.

By not having a marine solar vent, but a cheaper computer fan, it costs far less. Instead of a tiny solar panel on top of the fan, this method pinches some power from the main solar panels, but when we are not on the yacht, it would only go to waste.

Thanks for the ideas, very helpful.
I think I'll make a slot on the inside of the grate on the companion washboard, to drop in a computer fan (I like the look of that 2w silent one,cheers) to extract air while I'm not on the boat, when I'm on it being able to remove the fan would be handy if I need to put in the washboards to cross bars and not be faffing with the cord. Will need to get air into the pointy end berth so might add a low profile solar one there on the hatch, where there's already a bogged up hole, needs to be low profile so doesn't hit mast when it's open.
cheers