Next Gen 5.5 kW genset review

[a64pilot]

Originally Posted by colemj

There is a 6.2KW head on a 3.5KW generator?



I can't imagine what the water pump drive mode has to do with the generator head choice.



Mark

Call them, that is what I was told, but I'm pretty sure the 3.5 and 5.5 had the same Markon head, so the 3.5 has always had an oversized head.
The new Syncro head apparently has a PTO or similar that can drive the pump through a toothed drive belt, they couldn't drive the pump from the motor any longer due to a change Kubota made to the engine


Sent from my iPad using Cruisers Sailing Forum

[Hoghead]

Sounds like it will work fine for me and these little engines are common here on iron buffaloes, so it should stand up just fine. It is the non-Kubota marinization parts that interest me.

My application will only run for 1-2 hours a day to charge batteries and make water. Worst case aircon overnight if it is just too sweltering to sleep
I had a NL in the past on a trawler and this little one should do the job on the sailboat

My problem now is driving the watermaker pump.
I cannot find a 3 HP electric motor that the genset can start, or genset + Victron 3000

That leaves me with an engine driven water pump, but Next Gen cannot suggest how to drive this off the engine and all they offer is a different 80mm OD front pulley with a 6 groove flat serpentine type belt.
I however cannot find a 12V x 6 groove clutch to fit the pump, with a suitable diameter 5.25" pulley

This leaves me direct mounting the 6 groove pulley to the pump (if I can even find one) and slipping the belt on every time using a tensioner - not ideal

For some reason they are not suggesting a flywheel mounted pulley

The front Kubota pulley drawing is attached
I am having trouble finding a pulley that I could bolt to this Kubota pulley

Not easy to try and re-engineer this form Thailand!!
I would have thought that Next Gen had been asked this before, but apparently not?

Anyone done this?

[colemj]

How large is your watermaker that it needs a 3hp pump?

But even with a 3hp motor, the 5.5kW genset provides 33% more than the necessary running loads. I suspect it will start that motor - particularly since it is not loaded down when starting the watermaker (you will have removed any back pressure on the pump before starting).

Maybe a soft-start capacitor is all that is needed.

But I'm really interested in that watermaker size - that is a whopping big motor for a watermaker.

Mark

[Hoghead]

Originally Posted by colemj

How large is your watermaker that it needs a 3hp pump?

But even with a 3hp motor, the 5.5kW genset provides 33% more than the necessary running loads. I suspect it will start that motor - particularly since it is not loaded down when starting the watermaker (you will have removed any back pressure on the pump before starting).

Maybe a soft-start capacitor is all that is needed.

But I'm really interested in that watermaker size - that is a whopping big motor for a watermaker.

Mark

It is a General Pump WM 4215S and at 900 psi will need 2.58 HP, so a 3 HP single phase motor.
Even with a CAP start/run motor, Baldor and Leeson both tell me that while I can run this motor, it will not start on the genset. I do not have the start A on hand but it was a whopping number and more like LRA

[colemj]

Are you really shooting for an 80gph watermaker? That is what that pump will deliver, provided you spec the rest of the system for it.

Mark

[sailnow2011]

We have a phasor 3.5. Its really the same exact unit, with a few tweeks. I am building my own soundbox, but so far so good. It seems to start the 16K AC with no issue, and will actually drive the 16K AND a 1500w waterheater. Not for very long, and it gets very warm while doing it, but the waterheater only takes about 20-30min anyhow. Only long term issue I am having is the throttle solenoid. I would keep a spare on hand. I need to replace mine now, as you must go move it a few times before you try and start the engine.

I had some water flow back into the engine due to an exhaust issue. It seized a valve, and bent a pushrod. I got the PN, and ordered it from a kubota tractor dealer in Pennsylvania. Wopping $17 in parts and it was as good as new. That is really the best part. Being able to order parts from tractor dealers. You have to call around, because some price gouge, but you can't do that with a westerbeke.

[Hoghead]

Originally Posted by colemj

Are you really shooting for an 80gph watermaker? That is what that pump will deliver, provided you spec the rest of the system for it.

Mark

Driving a single 4 x 40 membrane at 900 psi in tropical waters.
Maybe 60+ and those are little US gallons. We are water hogs
I could raise the pressure a bit for higher output as you suggest

The pump is 990 + 221 for the clutch
Those are big US dollars

[colemj]

Originally Posted by Hoghead

Driving a single 4 x 40 membrane at 900 psi in tropical waters.
Maybe 60+ and those are little US gallons. We are water hogs
I could raise the pressure a bit for higher output as you suggest

The pump is 990 + 221 for the clutch
Those are big US dollars

Then I think you are looking at the wrong generator.

Mark

[Hoghead]

Originally Posted by colemj

Then I think you are looking at the wrong generator.

Mark

Please elabourate -if there is a better small package genset I am all ears.
this is in a sailboat so space is limited and while I like NL there is just no room, neve rmind the cost.
Duty cycle is likely 1 hour/day or overnight if running an aircon

The genset secondary function is to make water, and primary is as a generator.
I am fed up with the Little Wonder 12V watermaker I have now as the output is less than wonderful while the power consumption is spectacular. Since I want a genset anyway, the thought was why not upgrade the watermaker at the same time

I need to charge batteries, and since that there is now power, to run an aircon at night if it is too sweltering to sleep in the tropics.

[2hullvenus]

Originally Posted by Hoghead

Driving a single 4 x 40 membrane at 900 psi in tropical waters.
Maybe 60+ and those are little US gallons. We are water hogs
I could raise the pressure a bit for higher output as you suggest

The pump is 990 + 221 for the clutch
Those are big US dollars

Do you have a thread or some links to help those of us less familiar with watermakers to understand your system?

I'd like a very high output, short run watermaker running off my 5kw genset as well.

[Hoghead]

Originally Posted by 2hullvenus

Do you have a thread or some links to help those of us less familiar with watermakers to understand your system?

I'd like a very high output, short run watermaker running off my 5kw genset as well.

There is a good intro on DYI watermakers on Passagemaker - Google Passagemaker DYI watermaker
An excellent approach but it could be done a lot simpler if you are not that technically inclined.

I am using a 990.00 USD General Pump 4215S (stainless head) with the General supplied 221.00 Okura 12V clutch to turn it on and off while the genset is running. A CAT 310S stainless sleeved pump is cheaper but not sure about long term reliability. As noted above I do not have sufficient Amps to run a direct coupled motor unless willing to sacrifice flow rate.

The biggest obstacle is how to couple this to the Kubota engine on the genset and Next Gen does not have an off the shelf solution. Difficult to believe that no one has asked them to do this.

Proper gearing is the problem and I am going to have a special pulley machined to mount on the genset. Let me know if you want one and I can easily get another made at the same time and machine work is reasonable here in Thailand. Post is cheap

I will write all this up in the next week or so when finally engineered

[colemj]

Originally Posted by Hoghead

Please elabourate -if there is a better small package genset I am all ears.
this is in a sailboat so space is limited and while I like NL there is just no room, neve rmind the cost.
Duty cycle is likely 1 hour/day or overnight if running an aircon

The genset secondary function is to make water, and primary is as a generator.
I am fed up with the Little Wonder 12V watermaker I have now as the output is less than wonderful while the power consumption is spectacular. Since I want a genset anyway, the thought was why not upgrade the watermaker at the same time

I need to charge batteries, and since that there is now power, to run an aircon at night if it is too sweltering to sleep in the tropics.

Unfortunately, you can't wish high power into small, inexpensive packages. If you really need an 80gph water maker, you will have to provide it with the power it needs. If you can't provide that power, you will have to reconsider the watermaker.

Our previous watermaker was a Little Wonder 12V, and we came to the same decision as you regarding its suitability for our needs. We installed a 30gph watermaker to run off our NextGen 5.5kW, and have as much water as we can reasonably use.

I can't imagine what we would do with 80gph. There is simply no way two of us could use that much water - even letting the shower and faucets run continuously like people in houses do.

Watermakers need to be run often, and for longish periods at times, to stay healthy. It is better to run one for a couple of hours every few days, than to run for 1hr.

If you plan to run it 1hr/day, then choose a watermaker that will provide your daily allowance in that time - and choose a generator that will supply the power for that watermaker AND the battery charger.

You can't choose these pieces separately based on different requirements and demand they work together.

Mark

[2hullvenus]

Thanks for sharing, Hoghead.

Let me do that reading. I know for sure I won't need the gear, as I'd be running mine as a pump driven by the AC output of the generator. Not a Kubota.

[Hoghead]

Originally Posted by colemj

Unfortunately, you can't wish high power into small, inexpensive packages. If you really need an 80gph water maker, you will have to provide it with the power it needs. If you can't provide that power, you will have to reconsider the watermaker.

Our previous watermaker was a Little Wonder 12V, and we came to the same decision as you regarding its suitability for our needs. We installed a 30gph watermaker to run off our NextGen 5.5kW, and have as much water as we can reasonably use.

I can't imagine what we would do with 80gph. There is simply no way two of us could use that much water - even letting the shower and faucets run continuously like people in houses do.

Watermakers need to be run often, and for longish periods at times, to stay healthy. It is better to run one for a couple of hours every few days, than to run for 1hr.

If you plan to run it 1hr/day, then choose a watermaker that will provide your daily allowance in that time - and choose a generator that will supply the power for that watermaker AND the battery charger.

You can't choose these pieces separately based on different requirements and demand they work together.

Mark

How did you drive your pump?

The water output is a function of flow, pressure, and membrane size. I am only driving it at 900 psi at 4.2 USG/Min. These membranes can take a lot more than that, so the design is conservative to prolong component life.

The most cost effective method is to use a single 4 x 40 membrane. Far cheaper than 2 ea. 2.5 x 40's
Output therefore is partially determined by the this membrane price driven decision.

Yes I could use a lower rate pump but that again is a cost/benefit decision

I hear what you are saying but it just came together best like this and my 1 hour/day or 2 hours every other day duty cycle works for me.

If it is worth doing it is worth overdoing!!

[colemj]

The pump is driven with an electric motor using the AC output of the generator.

Again, if you are overdoing the watermaker, you must overdo the generator to run it. There is no free lunch.

The NextGen 5.5 does not seem to fit the bill here.

Mark