Water maker again

[sailaboutvic]

Hope we get a write up on completion Vic?
We are interested in some sort of low volume water maker but the DIY route seems to be the only way we can afford one!
If the pressure washer seems feasible and someone nearby has used one with demonstrated success then why not go down that route?

Hi Peter
Once it's finish I take some photo and send them to you if you like with info .
Hope you boat going well .
Back in Greece next year to sell other boat ,

 

[miyagimoon]

A cat 247 277 pump are what most people use with a DD onto an 1.5 HP motor , I have one good friend who putting one to gather as we speak ( thanks Albert if you reading this for the info you sent me and Chris ) .
My concern is I would need to run my 4kv gen , ok while it's working but if it ever stop that also mean no water maker ,
Anther thing to think about is the gen uses about 1 lts of fuel an hour , if we use it every day for water that's going to be expensive water .
With an power wash pump , we could run it on an inverter while we using the engine .
I agree an power wash pump not going to last long but @ the rate of a Cat pump , bell housing and motor , I could but 10 Power wash pump compair to one Cat .
Look at it another way if a PW pump last a season it will be 10 year before it cost me the same as a Cat pump and by then the Cat pump might be on it's last legs .
Plus with a power washer you will get most of the fitting and pipe work.
On the other hand if the PW pump is only going to last a few months , well then is not worth the trouble of keep replacing it.
Hence this posting here ,

Vic,
No problem sending you the info and quite rightly you should not take what I say as gospel and be asking others for their opinions .
I can only give my opinion which is based on my own experience and knowledge.

If you are seriously thinking of using a standard Pressure Washer Pump and associated motor on the grounds that it will use less power than a CAT Pump with 1.5kw Motor, hence allowing you to run it from your inverter. I would suggest you have a look at the power rating of these http://topreviews.best/main-review/...Fbt3IOqbk_ki53xsQQhmwx8FevzYz3D2j8aAk4I8P8HAQ. Now I know they are not necessarily the same pump and motor as those you are thinking of but it will give you an idea.

Now have a look at what d.c. current an inverter running a 1500kw load will draw from your batteries. Have a look at this https://www.batterystuff.com/kb/tools/ac-to-dc-amperage-conversion-run-through-an-inverter.html. The answer is 142 Amps.

Which brings on more questions such as what size inverter do you have, how large is your battery bank, will you only make water whilst motoring / motor sailing (bit restrictive), what is the fuel consumption of your engine and how much extra fuel is consumed when running the water maker. The list goes on and on.

At the end of the day it is your choice, we (I and many others on here can only give our opinions). What ever you chose make sure you have chosen for the right reasons. We have all learned from our mistakes, I have on many occasions learnt that cheap and cheerful does not really work on a boat.

 

[Kelpie]

I found this idea quite interesting but I cannot find any pressure washers that are less than 1400w/240v (smaller 12v and rechargable units are only about 100psi). It's a shame, because if somebody produced a model inbetween these, e.g. a 1000psi 12v device, it could make an excellent starting point for a small water maker.

 

[geem]

Vic,
No problem sending you the info and quite rightly you should not take what I say as gospel and be asking others for their opinions .
I can only give my opinion which is based on my own experience and knowledge.

If you are seriously thinking of using a standard Pressure Washer Pump and associated motor on the grounds that it will use less power than a CAT Pump with 1.5kw Motor, hence allowing you to run it from your inverter. I would suggest you have a look at the power rating of these http://topreviews.best/main-review/...Fbt3IOqbk_ki53xsQQhmwx8FevzYz3D2j8aAk4I8P8HAQ. Now I know they are not necessarily the same pump and motor as those you are thinking of but it will give you an idea.

Now have a look at what d.c. current an inverter running a 1500kw load will draw from your batteries. Have a look at this https://www.batterystuff.com/kb/tools/ac-to-dc-amperage-conversion-run-through-an-inverter.html. The answer is 142 Amps.

Which brings on more questions such as what size inverter do you have, how large is your battery bank, will you only make water whilst motoring / motor sailing (bit restrictive), what is the fuel consumption of your engine and how much extra fuel is consumed when running the water maker. The list goes on and on.

At the end of the day it is your choice, we (I and many others on here can only give our opinions). What ever you chose make sure you have chosen for the right reasons. We have all learned from our mistakes, I have on many occasions learnt that cheap and cheerful does not really work on a boat.

Our watermaker uses a cat 247 and a 1500 w direct drive moter. Our generator is 4kw. We only use the generator to make water but at the same time we often put the mains charger on (900w) and the immersion heater (1200w). Our boost pump is 220v and uses 175w. The generator will run all of this.
Should the generator fail, which it has once when an injector went down and I didnt have a spare, we have a 3000w low frequency inverter. This will run the watermaker but we need the engine on with the alternator and smart charger. We have a 450amp hr battery bank @24v and a 60 amp alternator @24v. We still have about a 50 amp deficit but since we only run it for 1/2 hour stints in this situation we can cope. We can make 65 litres in 1/2 hr.
You need a LF inverter to reliably run and inductive load ike a watermaker pump. It should be rated at twice the running current of the motor. Hope this helps