Integrated Generators GPX-5/6

[Leesmob]

This is my first attemps at posting a thread and I suppose like many I am looking for advise. My wife and I are about to set sail on the uncharted ocean of retirement and in preparation I am fitting out our Seawind 1160 Sirocco for live aboard. During my internet searches for a suitable 240v marine generator I came across the Mastervolt GPX-5 & 6 integrated units.
The concept makes sense to me although my electrical knowledge is limited to two undeniable facts- "If you touch it it can kill you & If you don't pay the bill it will be cut off".
Currently Sirocco copes well with a bank of AGM's and a couple of solar panels, but I want to fit an A/C unit and thus the extra power requirement.
I have been unable to find any reviews or assesments of these power systems other than the glossy presentations from the manufacturer and vendors.
Has anyone had hands on experience with them?

Alan Lees
Deep in the Heart of Darkness on the Purari River PNG

[CharlieJ]

I am a huge supporter of e-propulsion (designed them), hybrid systems (designing one) and lithium iron phosphate (LFP) battery (designed and installed one) technology. These new programs are the wave of the future and are to marine electrical systems what fiberglass was to wood as a boatbuilding material!

That being said, the GPX-5 is a brand new system, with no track record that I am aware of. If you want to be on the bleeding edge of technology, then you really should talk to Mastervolt directly to get more info and find a good marine electrician/engineer to help you with your decision process. Tread carefully.

Charlie

[Dockhead]

The Mastervolt GPX-5 is much more than a generator. It's a whole hybrid drive system. Do you want to convert your drive or do you simply want to generate AC power?

If you want to generate AC power, then my advice to you -- with the usual disclaimers that it is my subjective opinion, YMMV, etc. -- is to strictly follow KISS.

A generator set is one of those things which should be as simple and reliable as possible. Gensets are one of the most troublesome items of equipment on board, so avoid the ones which are delicate, overstressed or overcomplicated.

The usual solution is to buy a heavy duty low RPM (1500 RPM for 50hz power) genset like a Kohler, Onan (Perkins), or Northern Lights. I have a 6.5kW Kohler with a 1,000cc three-cylinder Yanmar and love it. It is quiet and the quality of the sound is also pleasant -- a low loping murmer which doesn't disturb anyone. This type of genset is supposed to be good for 10,000+ hours -- for practically continuous duty -- and is extremely simple.

The problem for you is that this type of genset is heavy, and you have a smallish catamaran which will likely tolerate neither the volume nor the weight of something like that. You might be forced by these constraints to go with a Fischer-Panda, but I would advise you to avoid that if at all possible. These are complicated, poorly engineered, and notoriously unreliable, but -- they are the most compact and lightest units you will probably find.

Maybe you can get by with a high RPM (3,000 RPM) Onan or something like that.


One very important point -- don't oversize the genset. Don't size it for startup loads of your air conditioning -- you can deal with those with the Power Assist feature of a Victron inverter/charger or similar functions of other similar inverter/chargers. Two reasons -- the genset will be happier if you can keep it loaded up to 40% -- 50% of capacity most of the time, and a smaller capacity genset will be lighter and less voluminous, which will be very important installing in something like your boat.

[djmarchand]

No hands on experience but I have researched them. Apparantly they are currently only 50 hz and the US dealers haven't heard of them. Can't tell if you are in 50 hz territory or not, but if you need 60 hz, that would be a show stopper for me. No doubt the inverter can be tuned to produce 60 hz but if there are no US dealers, then what do you do?

Generator/invertor technology isn't new. Honda popularized it some years ago, but heck even the Chinese build them now. Mastervolt seems to be the first to integrate a small marine diesel with an inverter.

It is a very nice concept and solves the problem of underloading your genset. You can easily run your medium sized A/C all night long without worry about glazing the cylinders of your genset due to very light loading. Mastervolt's genset will start and stop as needed to keep the batteries charged and the charging will keep the genset loaded.

As an accompanying piece to sell the hybrid system no doubt, Mastervolt published a study of the efficiency of lightly loaded gensets, Impressive data and anyone who goes to that much trouble must be pretty serious about their product.

It must be expensive however.

David

[Bill Burgette]

Wow, just spent about an hour on Google and YouTube and that looks like a really nice system. As mentioned above a talk directly with the manufacturer will give some needed info like........cost. It appears to be a 3.3 KW electric start single cylinder diesel generator working in conjunction with a 2 KW (continuous) inverter. From the brochures it appears that it is capable of inverter power battery charging and direct generator output simultaneously.

I say this because it is rated at 5KW continuous with a 10KW (for 5 seconds) starting load. That extra oomph may come from a monster capacitor and relay circuit in conjunction with the intermittent rating of the inverter. It is also capable of 100 amps of battery charging with variable charging curves based on the type of battery.

I really like the concept. You wake up and turn on your 1.3 KW coffee pot (assuming electric and not a percolator) and just the inverter takes care of that load. The Admiral plugs in her 1.5KW hair dryer and the unit knows that the inverter can no longer fill the demand so it starts the generator. Hair gets dry and the genny shuts down and continues to make coffee on inverter power.

All day long the inverter handles most of normal loads until the batteries get to a preset discharge and this unit starts the genny to recharge the batteries. No more worries about when to charge and at what percent for max battery life.

Everything that this unit does can be accomplished by other means but I've not seen a simpler system. Variable speed diesel based on load......nice, fuel savings have got to be there.

I did not see a price listed anywhere and although I like it, I'll also bet that it will be a lot more inexpensive to buy separate components but the size looks very favorable. About 20"x18"x26" and only 175 pounds for a water cooled electric start genny, inverter/charger and a start circuit capacitor/relay for excess loads. Now where do I have an extra 2 foot by 2 foot hole to put it in?

[Leesmob]

I just had a response from the Mastervolt agent in Australia:

"The GPX unit won’t be available until Dec/Jan. The original GPX-5 was superseded to the GPX-6 before it’s intended release earlier this year. At this stage we don’t have any pricing from Mastervolt until closer to the release date. We expect the pricing to be around the $16-18k mark."

I don't need the gen for 12 months yet, so I might just wait and see. The price is no surprise.

[djmarchand]

Wow, $16-18K Australian!!!

A similar, but not as efficient system could be built with:

NextGen 4 KW genset $6,000 (US)
Victron 4 KW Inverter (with genstart feature) $3,000

For about half the cost of the MasterVolt system.

It wouldn't be as efficient as it isn't a variable throttle, inverter generator. But the generator will start when the batteries are low and turn off when charged. It won't automatically tie both AC supply sources together, but if you know your loads are going to be high or you need motor starting current, startup the genset and the inverter will sync to it.

[Leesmob]

Originally Posted by djmarchand

Wow, $16-18K Australian!!!

A similar, but not as efficient system could be built with:

NextGen 4 KW genset $6,000 (US)
Victron 4 KW Inverter (with genstart feature) $3,000

For about half the cost of the MasterVolt system.

It wouldn't be as efficient as it isn't a variable throttle, inverter generator. But the generator will start when the batteries are low and turn off when charged. It won't automatically tie both AC supply sources together, but if you know your loads are going to be high or you need motor starting current, startup the genset and the inverter will sync to it.

Now there's a sensible approach. I can't find a 4 KW NextGen, but they have a 3.5 KW unit NEXT-GEN - Marine Power Units sporting a 5.0 KVA generator end which they claim will handle a 16,000 BTU A/C.
Now I have a dilemma, the technophile in me loves the idea of the Mastervolt system, but then I figure the price difference will pay for a lot of fuel. I guess that sanity should prevail and the practicality of the NextGen will win out.
The local dealers here in Aus. (including Seawind themselves) would like to see me fit a Panda, but what I read on the web don’t make this a comfortable decision for me. Too many bad reports. Besides which at AU$12,360+tax they are almost as expensive as the GPX-6
I have also been looking at the Norpro 5NY, but at 365lb for the enclosed unit it is a big lump of iron to be carrying on a 38’ cat. I do however like the 5 year warranty.
I would be interested to hear any experiences with the NexGen units – reliability, service etc.

Still stuck up the Purari waiting for the rain to clear.

[CharlieJ]

I have been very impressed with the NextGen gensets. They are well engineered, have all the items that require Owner maintenance on one side of the engine, and are relatively quiet. They do have a very simple voltage regulator and the output, esp. in the smaller units, can be somewhat ragged and this can cause problems with a sophisticated inverter/charger as the input AC is not "qualified". They may have corrected this problem in the last year or so, but a conversation with them is warranted.

BTW, Phasor Marine Generators http://www.phasormarine.com also offers a line of gensets that should be candidates. NextGen split from Phasor (or the other way 'round) some years ago. Interesting to note that the Phasor specs for their K3-6.5kW genset show a voltage spec of +/- 1%. Nothing about waveform though.

Charlie

[Finistere]

We have had an Entec West 4kw for the last six years, reasonable price, simple reliable and the Prosine 2000 has no problem with it as a charging source. Generator and motor are fresh water cooled, no ventilation required except for air intake.

http://www.entecwest.com/