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3K Unit?


NotMario
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So we tried doing a 3kw unit the first time around...but didn't have a single pre-order for it.

Problem is that the bulk costs of the unit remained largely the same--as basically only the transformer (and FET boards) changed.  And everyone looking at it decided that it didn't make sense to spend just 1/5th less to get 1/2 the wattage.

The only way to get a financially viable 3kw unit would be to do a radical redesign of the concept...no stacked mainboard/control board combo, don't need the huge heatsinks, etc.  Reducing size & weight (and hopefully costs) would be a requisite in order to make it financially viable.  But all of that requires a significant amount of R&D costs--and would we sell enough 3kw units to make it even financially worth it?

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Yeah, who knows.

I would do a 6K unit, but this application prohibits the size of one.

Can't say for sure. It's your business. 🙂
I do know that with a 12K and 6K, you cover a good portion of the market, but leave a couple of significant niche applications out; RV and Marine.
While there are no doubt applications for the 6K in those niche markets, the 3K would be more appropriate for many cases.

Sometimes paying 4/5th for 1/2 is reasonable because the application mandates it. The justification is the lower Idle draw of your units.
My 1K pulls nearly as much idle draw as your 6K unit. Of course there are other reasons - like simple integration with a control panel. Sky's the limit.

Just my 0.50$. I knew you had one in the past, was just curious about it.

Edited by NotMario
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While there are no doubt applications for the 6K in those niche markets, the 3K would be more appropriate for many cases.

Victron has the RV  and maybe marine  market for the 3 kw inverter .    Competing with Growatt in the 12kw market is difficult  enough  but competing  with Victron is something  I   would not try .      

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I'm not suggesting anyone do anything. I'm only pointing out a gap in the market -- seeing as i have a use case right inside that gap, i figured i'd ask about it.

I'm not particularly fond of Victron's line of inverters. Though i do like their monitoring equipment - the GX is the only thing they make of interest IMO.

Competing with anyone is difficult. That's capitalism for ya.
Pretty sure the market for a 3K is much larger than for a 12K. Granted there is less competition in the 12K market. I still wouldn't dismiss it so readily. But that's not my call.

 

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2 hours ago, NotMario said:

The justification is the lower Idle draw of your units.

...shhhh....don't tell anyone that a few quick tests I did this week showed that it MIGHT be possible to reduce the no-load draw even further.........like 15W idle for a 12kw inverter (instead of the current ~50W for a GS12, which is compared to the "industry average" of 150-180W)...

 

2 hours ago, NotMario said:

Just my 0.50$. I knew you had one in the past, was just curious about it.

Yes, I hear ya.  Sean wants to get in every single market out there, but he's not on the design side of things 😉.

I do see where a 3kw unit could be quite viable.  Thing is, I'll have to redesign every single board, the case, and transformer to get stuff small enough--so it will take a considerable amount of my time.  If there's a solid market for it...well...definitely worth considering I guess.

It would still maintain the universal transformer design (i.e. 12/24/36/48 input), though I'm considering perhaps 120v only output.  (That'd considerably simplify the control board requirements).  Reason being, a 240v split-phase output is kinda limiting at 1500W/phase.  A standard 120v circuit is 1800W.

Big challenge for me is figuring out how to redesign the MOS boards/mainboard in such a way to considerably reduce the footprint and space requirements--yet still maintain a modular/serviceable design.  12v @ 3kw is still a cool 250A--not too terribly bad I suppose, but still significant.  I would expect 12v to be a lot more common on 3kw inverters.

 

2 hours ago, NotMario said:

I would do a 6K unit, but this application prohibits the size of one.

So...the redesigned 6kw unit is notably smaller than the one you currently have.  Way smaller, in fact.  I posted the dimensions here:

Maybe the redesigned unit will be small enough for your requirements?

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It's that width that kills it. That tranny can only be so small!

It does occur to me that i might be able to use a different location that could possibly accommodate those dimensions. I'll have to take some measurements to see if it might work with that shorter profile - at least i think it's shorter... I think the width might still be a problem in that spot, too.
The wiring would be considerably complicated, but everything else would be better off.

The 12v to 120v use case is going to be the most common in that power tier - by far. The "RV Life" is a growing market. Low idle draw, configurable power-save timing, remote-control, and monitor integration are areas where a vendor could stand out - the latter 2 being where victron stands out IMO.

All i can say is WOW. 15w for a 12K unit? Have you come up with something that scales logarithmically? The GS6 was already good at 30ish watts...
At those levels, even a programmable monitoring system will be a significant factor compared to the inverter. A 20W full system standby would be amazing, especially when you could get it down even more with intelligent power save functionality.

Anyway, food for thought. No doubt the off-grid industry you currently target is growing big-time. And that will just accelerate faster with the price of energy rising like it is, not to mention all the rolling power outages. I just helped a friend with some decisions to start his journey, and more are beginning to think about it more seriously..

Edited by NotMario
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8 hours ago, NotMario said:

All i can say is WOW. 15w for a 12K unit? Have you come up with something that scales logarithmically? The GS6 was already good at 30ish watts...

It's a theory right now, based on testing with a huge E-core transformer (comparable to the 12kw spec) from an old commercial-scale charger.  I haven't actually tested the theory on a spec GS12 transformer--but when I get a chance, you bet I will.  It may be that good, it may be a tad worse--I don't know.  The challenge will be reducing the no-load current without compromising with an increased output sine THD level.

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Well, I've done a bit more measuring...let's just say that my numbers were a little overoptimistic, resulting from me not remembering the actual numbers.

I was thinking that the magnetization current of the GS12 transformer was 9W (compared to the E-core at 40W)...but alas, it's actually ~22W.  Add logic boards, FET drivers, switching losses...and I guess a no-load of 39W on the GS12 preproduction unit isn't all that bad.

Still there's potential room for improvement.  For off-gridders, every watt helps!

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