Powering Electric Toilets

[BrightSEALAB]

So the next item on my list is replacing two heads and all the hoses. I've got two questions here and I have no idea just how dumb these will sound out loud...

First, I'm going with electric toilets and was originally considering the Raritan SeaEra QC because it was less demanding on the electrical system. The old heads were Jabsco manual and DC wiring would have to be run a ways to get to each head. The SeaEra draws 10Amp and the Raritan Marine elegance required 18Amps.

But ... I like the Marine elegance, and more importantly, my wife likes it a lot more. So here I am pondering these DC cable runs and I stop to look at the AC outlet running right past where I'm working.

It's rated at 120VAC 15AMP. I can put a DC Power Supply on this to get me my 12V 20Amp and barely pull 2 amps from the AC circuit to do so.

Has anyone ever run a DC toilet off an AC power supply?

Second Question...
If I get this far, I thought I would put a battery backup in each head for times when we are underway. In each bathroom there is at least one wonky shaped tiny cupboard that isn't really being used for anything. A 12vdc 10AH LifePo4 battery would fit easily and power a couple days worth of flushes before we had to resort to running the inverter. It could even be charged off the low current DC circuits already present for the lighting.

Any reason this is a bad idea? I'm not looking to argue, I come up with bad ideas all the time. Some of my 'best' ideas turned out to be bad ideas.

Thanks.

[SailingPNW]

How far away are the toilets from your panels or batteries? Unless you just have no way to run new cables or the distance is significant, you would probably be fine with 8 awg wire which isn't to bad to run. I think I would avoid the hassles of extra batteries, chargers, and trying to use the AC system.

[BrightSEALAB]

Originally Posted by SailingPNW

Unless you just have no way to run new cables or the distance is significant, you would probably be fine with 8 awg wire which isn't to bad to run. I think I would avoid the hassles of extra batteries, chargers, and trying to use the AC system.

One head isn't far, the other would require a new 30' run of 8ga. At the same time, that AC line is just already there and more than capable of driving a 20AMP 12v DC supply. It's just... already there and the lazy version of me (my best me sometimes) would rather not pull 60 feet ($140) of wire. And if I ever want to convert it to selectable raw water I'll need to use 6AWG.

Meanwhile a set of wires with more than enough power handling is already ... right ... there.

[peghall]

The wiring specs and instructions in the "Installation, Operation and Maintenance Instructions" (aka "owner manual) for the toilet include the correct wire size for the distance (always round trip, not one way) from the power source.

As for powering it with AC current instead of 12v, that's a question for Raritan tech support. Give 'em a call 800-352-5630. I'd wait till after the Memorial Day weekend to do so.


Re your plan to put a battery for each toilet in the head that can be recharged when they get low... That means the toilets are likely to be used when voltage to 'em is less than the full 12v they're designed to use. And low voltage to a toilet--any electric motor--is highly damaging to the motor, in fact is also the most common cause of sluggish discharge. The main reason why electric toilets should always be on their own dedicated circuit shared by nothing else--not even cabin lights--that can pull power away from them So I'd rethink that plan if I were you.


--Peggie

[RaymondR]

You may need bigger water hoses as well, at least the long run one.

The trickle charging buffer battery is not a bad idea, people often do something similar with anchor winches.

[AndyEss]

I replaced my mechanical pump toilet with an inexpensive West Marine electric toilet. The existing wiring to the head couldn’t support the toilet macerator pump. I mounted a small LFP battery in a cabinet next to the toilet, which charges from existing wiring.
This setup works just fine in my situation, but I admit spending as little time as possible sitting on the toilet and repeatedly flushing it.
I don’t like your 110Vac circuit solution - 110Vac anywhere on a boat where water and plumbing is nearby gives me the heebie-jeebies. Is the outlet you are contemplating using GFCI protected at least?

[Lepke]

I have Incinolet toilets and run them off a Magnum inverter 120/240v.

[Jolly Roger]

Your wife is right to favor the Elegance electric toilet. It was one of the first modifications I made when I bought my boat ten years ago. I also made a freshwater flush system, which can be easily switched to seawater on passage. Both toilets also have separate Raritan Purasan treatment systems, (not electrasan). I haven’t had any problems with the power supply, but my boat has a large battery bank and a 6.5 Kw generator as backup.
You could look at these articles on my website for an overview.
changes to the aft cabin in the boat (schooner-britannia.com)
Installing two electric toilets (schooner-britannia.com)