Plastic Classic Forum

I am planning to replace my 5 gallon Porta-Pottie with an Airhead composting toilet on my Alberg 30. I plan on using the 12v fan provided. As it needs to run continuously, what is the preferred method of wiring to the batteries. I keep my main battery switch on off when leaving the boat unattended.
Thanks,
Marcelo

You can run the wires direct to the battery post or to an unswitched bus bar near the battery where you connect your bilge pump and solar. Although you may want the fan to run continuously when the toilet is holding waste, there are times you want it turned off so it needs to have a switch, preferably near the fan or toilet. I connect the fan switch to the same circuit as cabin lights or other 12v fans and don't mind leaving those powered when off the boat. You may need to add a terminal block to share the same feed line on port or starboard side from the cabin lights circuit switch. Or if you have a spare circuit switch on the main panel you could run the toilet fan wires all the way there for its own separate circuit.

At 7:30 in the following video you can see how I added the terminal blocks in plastic boxes for cabin lights and fans on each side of the boat amidships:

https://www.youtube.com/watch?v=PofFOg9H_6Y

Here you can see the fan switch I installed here:

https://www.youtube.com/watch?v=KrNvitLukLU

And here is another simpler toilet bucket version:

https://www.youtube.com/watch?v=98-QMvATkj4

Thanks for the reply. When the boat is unattended with the main battery switch off, the only active feed is to the electric bilge pump which comes directly off one of the batteries with an inline fuse. Therefore, I am wondering how to power the fan while everything else is off.

I edited my post above to reflect your concern. You can run the wires direct to the battery post or to an unswitched bus bar near the battery where you connect your bilge pump and solar. You still need a switch and fuse to turn it on as seen in my videos. I know it's a habit for many people to turn off the main battery switch when leaving the boat but as long as everything is fused and you turn off unused circuits then I don't see a danger with that. But since many people want to be able to turn off the main switch and leave the vent fan on, in future I may wire it direct to the battery as well.

Perhaps you could use a solar powered vent at the top of your stack, instead of a wired in computer fan...?
https://www.defender.com/category.jsp?i ... 80|2290139

My experience with my cheap homemade composter, when using both peat and coconut coir as a medium and providing a free flow of air to the bucket was that a fan wasn't needed, no smell was evident. There was a 2"+ gap all-around at the top of bucket providing airflow. No-see-um or skeeter netting to keep flies out of the soil is a necessity.

I stopped using those solar vent fans because they changed and cheapened the construction of them several years ago so that now they are expensive and break down within a year in many cases. The ones they sold some 20 years ago were much better and fairly long-lasting.

Bad and Good news, I guess, as I have an old stainless one of 80's/90's vintage still on the shelf.

While looking for the Defender link, I did see this IP65 solar vent fan. The fan itself has an inline plug, perhaps when off-boat you could route that out thru the vent to the panel, and when aboard, run the fan off the mains, switched like you do, James...? At only US$22, might be worth a try if keeping the fan from drawing on the house bank is a priority, though some of the reviews indicate that your expectations should meet the price.

https://www.amazon.com/DestinyBliss-Pow ... B07V1MXBGP

Alternatively, at a bit over 0.10A/h it'd take a long time for one of these fans to have much effect on a Grp 24/27 battery. You could brew your own recharging system w/a panel that would more than make up for the fan for well under US$50, all in. That's a lot cheaper than the now-dodgy solar vent discs...