Water maker wiring

[hoppy]

I need to wire up my 12v watermaker compressor. It was suggested to me that I should run the wires from the battery via a dedicated on/off dial switch rather than connecting it to the existing house bank switch.

Down the line from either switch options will be a 60amp fuse and a relay switch that is connected to the WM control panel.

Is it necessary to have the dedicated on/off dial switch?

Perhaps I can use the existing house dial switch and then replace the 60amp fuse with a 60amp breaker switch from a windlass. Then if the relay switch gets stuck on I can trip the breaker.

[Terra Nova]

Run it from a breaker on the panel.

[hoppy]

I have for the control panel but the compressor requires a 60amp fuse and 16m2 cable but only if it's less than 5m, otherwise it's 25m2


Sent from my iPhone using Cruisers Sailing Forum

[a64pilot]

I would treat it like any other high amp load, like a windlass for example.
I would wire directly from the bank to a circuit breaker like ones used for a windlass, that is also used as a switch.

On edit, I would put this breaker / switch as close as is possible to the house bank

[sailjumanji]

Shortest wire run possible direct to the batteries, with a dedicated circuit breaker in line. Run large gauge wire to prevent voltage loss. Watermaker efficiency is a function of voltage. You get more water at 13.3 volts than 12.5 volts. Why we run ours in the middle of the day when solar panels are really cranking out amps and volts.

[fallingeggs]

I bet you could have the best of both worlds using a relay. Big, short wires between the bank and watermaker, with a relay in between, operated via a switch on the breaker panel.

Bank -> on/off switch (for entire bank) -> positive load buss bar -> fuse -> normally open relay (operated via breaker panel) -> watermaker.

A 70 amp relay is $5 (the LiFePO4 folks use them for their high voltage cut offs). Haven't actually tried this, but it's my plan. Maybe you can text it out!


Sent from my iPhone using Cruisers Sailing Forum

[hoppy]

I'm kind of reluctant to connect directly to the house bank as I don't want to have another "switch" to remember to turn off, especially as there is no way for me to add the switch in the same location.

In the photo, the house bank switch is on the far right and directly below it is a 100amp fuse. I am now thinking that maybe I could connect the cable to the 100amp fuse, so the combined WM & normal house load never stresses the cable to the switch (The load on the house battery is rarely above 10 amp). To the cable I add the 60amp fuse to protect the WM compressor. So I can shut off the power to the WM but with the house on, I can add a circuit breaker (can only find a 70amp)

The WM manufacturer recommends a 16m2 cable up to 5 meters, with this setup, even including the run from the battery to the switch it should be 4meters max.

[sailjumanji]

You've got my recommendation. Wire it just like the windlass - a switch, a breaker, and direct wire to the battery bank. Water output is direct function of voltage. Plus note that wiring size recommendation is usually written based on total length of the positive and negative wiring run from the battery, I.e., it's both ways.

[smac999]

you don't direct wire a windlass or winch to a house battery. they all come off the house switch. I would wire it after the house switch, but not on the 100a breaker. you can't add a 70a load to an existing 100a circuit... just wire from switch output to new 70a breaker. and maker sure wiring from switch to battery is big enough to handle 170a. probably should be 2/0

[captainjay]

Yep off the house switch then directly to your 70 amp breaker. Turning off the house switch will still kill all of the loads.

[hoppy]

I had a sparky onboard to have a look. He highlighted that I will need larger than 16mm2 cable because of the distance and can source a 60amp breaker, so I can skip the fuse. The will run it from the house bank switch. When I expressed concern about drawing the full 50amp from the watermaker and 100amp from the rest of the house (don't have anything that can do it anyway) he said that the cable to the battery can handle that load and more.


Sent from my iPhone using Cruisers Sailing Forum

[sailjumanji]

Oops, my bad. Nothing directly to a battery post. Everything to the selector switch.