Is running my water maker going to kill my batteries

[Ruso]

Dear Sailors,
Today I started first time the watermaker on my new boat together with PO.
He told me he always run the watermaker with engine running - kind of expensive option...
I have:
4 6V golf carts batteries producing 12V - total capacity 440Ah
Watermaker draws 14 A
Engine generator 70 A
Is rapid discharge (no engine running) going to kill my batteries?
I have solar 400 W and Honda 2000i generator and I can run the shore power charger on it.
Please share your opinion.
Many thanks

[BillKny]

Originally Posted by Ruso

Dear Sailors,
Today I started first time the watermaker on my new boat together with PO.
He told me he always run the watermaker with engine running - kind of expensive option...
I have:
4 6V golf carts batteries producing 12V - total capacity 440Ah
Watermaker draws 14 A
Engine generator 70 A
Is rapid discharge (no engine running) going to kill my batteries?
I have solar 400 W and Honda 2000i generator and I can run the shore power charger on it.
Please share your opinion.
Many thanks

To answer the question that you specifically asked: No. Drawing 14 amps from a 440 A-hr battery bank will not damage the batteries. No way, no how. This is not even remotely close to "rapid discharge" for these batteries.

But...

There is more to it than that. The power you use to run the water maker needs to come from SOMEWHERE. You need to produce it. You can either make it while the water maker is running, or later to recharge the batteries. You have not supplied nearly enough information to help you decide what the best and most economical way to generate this power is. There are a thousand
variables...

[Ruso]

I can run generator plugged into 120V on-board circuit and batteries will be charged through the on-board charger.

Originally Posted by BillKny

To answer the question that you specifically asked: No. Drawing 14 amps from a 440 A-hr battery bank will not damage the batteries. No way, no how. This is not even remotely close to "rapid discharge" for these batteries.

But...

There is more to it than that. The power you use to run the water maker needs to come from SOMEWHERE. You need to produce it. You can either make it while the water maker is running, or later to recharge the batteries. You have not supplied nearly enough information to help you decide what the best and most economical way to generate this power is. There are a thousand
variables...

[LoudMusic]

It depends on the power supply capacity ratings for your batteries. Looks like it's pretty high though - upwards of 75A per battery? I think you're good to go on draw

https://www.trojanbattery.com/pdf/ProdSpecGuide.pdf

The next problem is calculating how long you plan to run it in a certain amount of time, and being aware of your battery's state of charge. But that invites discussion about everything else you're running on board, like refrigerators, computers, and any kind of temperature and humidity control.

[sailinglegend]

Originally Posted by Ruso

I can run generator plugged into 120V on-board circuit and batteries will be charged through the on-board charger.

Don't run a watermaker in a marina or even in an anchorage with other boats there. Go snorkeling and see what floats past you!

Our 70 Lts/hour watermaker takes 29 amps so we used to only make water whilst motoring - making sure we weren't directly behind another boat who could be discharging their tanks. Now with 450 watts of solar and a 400 watt wind gen and 630 Ah service battery making water is not a problem without the engine running.

[Ruso]

Originally Posted by LoudMusic

It depends on the power supply capacity ratings for your batteries. Looks like it's pretty high though - upwards of 75A per battery? I think you're good to go on draw

https://www.trojanbattery.com/pdf/ProdSpecGuide.pdf

The next problem is calculating how long you plan to run it in a certain amount of time, and being aware of your battery's state of charge. But that invites discussion about everything else you're running on board, like refrigerators, computers, and any kind of temperature and humidity control.

My batteries not Torjan (I have to dig under the pilot berth to find out the batteries brand) but I think they all similar discharge rates.
I have fridge which draws about 3 Amp - I can shut it down while running the watermaker for couple hours. Nothing else high energy consumption.

[LittleWing77]

Originally Posted by sailinglegend

Don't run a watermaker in a marina or even in an anchorage with other boats there. Go snorkeling and see what floats past you!

I expect you were only joking, SailingLegend.

One should NEVER swim in a marina nowadays, you risk electrocution by stray voltage.

LittleWing77

[Jim Cate]

Originally Posted by LittleWing77

I expect you were only joking, SailingLegend.

One should NEVER swim in a marina nowadays, you risk electrocution by stray voltage.

LittleWing77

LW, while there is some danger in fresh water, in salt water there is no such worry. Consider the hull cleaning divers who spend all day, every day swimming in marinas.

And re the concern about making water in areas where folks are possibly discharging sewage... bacteria and virus are far bigger than the molecular NaCl and other salts which are being filtered out by the RO membrane. You may find it intellectually disgusting, but the water quality will be OK.

Jim

[noelex 77]

Originally Posted by Ruso

Watermaker draws 14 A

Is that 14A @12v or 120v ?

[LittleWing77]

Originally Posted by Jim Cate

LW, while there is some danger in fresh water, in salt water there is no such worry. Consider the hull cleaning divers who spend all day, every day swimming in marinas.

And re the concern about making water in areas where folks are possibly discharging sewage... bacteria and virus are far bigger than the molecular NaCl and other salts which are being filtered out by the RO membrane. You may find it intellectually disgusting, but the water quality will be OK.

Jim

Thqnks for that reminder, Jim. I obviously had my freshwater hat on and didn't realise it.

In the Great Lakes (fresh water), swimming is not permitted in any marina - due to stray voltage.

[chrisr]

on our boat our watermaker produces 80LPH and draws abt 6 amps - AT 240v AC

we have a 4000w inverter and 650 ah batteries (with 675w solar + 400w wind) and there is no way we can run the w/m from the batteries without running an engine or 2. the drain is enormous...abt 130 amps @ 12v DC i think

if your w/m is only drawing 14 amps, what is the output ? how long are you going to have to run it to produce a worthwhile quantity of water and will you flatten your batteries doing so ?

as an aside : there is no problem to run your w/m in crappy (pardon the pun) water. all that happens is you will clog your pre-filters more quickly. the membrane removes all nasties

lots of communities all over the world use recycled water this way every day

cheers,

[sailinglegend]

Originally Posted by LittleWing77

....One should NEVER swim in a marina nowadays, you risk electrocution by stray voltage....

I agree, which is why swimming is not allowed in most marinas. I was talking about snorkeling in an anchorage - and what flows past you!!!!!!!

[sailorboy1]

Originally Posted by Ruso

Dear Sailors,
Today I started first time the watermaker on my new boat together with PO.
He told me he always run the watermaker with engine running - kind of expensive option...
I have:
4 6V golf carts batteries producing 12V - total capacity 440Ah
Watermaker draws 14 A
Engine generator 70 A
Is rapid discharge (no engine running) going to kill my batteries?
I have solar 400 W and Honda 2000i generator and I can run the shore power charger on it.
Please share your opinion.
Many thanks

You can run your WM on the batteries. That 14A isn't "rapid" discharge far as your batteries go. This is just part of managing your battery charge like always. You of course may need to run one of your powered charging sources at same time to keep up/charge while using the WM.

[GreenWave]

Originally Posted by Jim Cate

LW, while there is some danger in fresh water, in salt water there is no such worry. Consider the hull cleaning divers who spend all day, every day swimming in marinas.

And re the concern about making water in areas where folks are possibly discharging sewage... bacteria and virus are far bigger than the molecular NaCl and other salts which are being filtered out by the RO membrane. You may find it intellectually disgusting, but the water quality will be OK.

Jim

The problem making water in a port or marina is not the filth it is the oil products possibly in the water. Unless your setup has a very good oil/water separator you risk ruining the membrane. That is expensive water.

[moseriw]

Can I run a powerboat with my bicycle generator?