High Frequency vs. Low Frequency Inverter - Does it matter??

[CoolWill]

The Genetry Solar 12 kW idles at about 30 watts unloaded. There's a generally negative opinion about them, and in dealing with them I'd say it's earned. But not for the inverter. The inverter is 100% tank. Super solid machine and way under priced.

 

[Crowz]

Imagine how many "my 800lbs inverter fell off the wall because I out 1x 1/4" Wood Screws in the wall"

Or "why do I keep running out of battery in the middle of the night?" "Because your inverter has way too much idle draw".

We can go round and round about it. At the end of the day, I agree that the LF inverter has its place, and is necessary, but its not for everybody, and not even for the majority of people.

I personally would rather have 2x HF inverters that can start my offgrid AC and Well pump, and maybe even add in a SoftStart to make my AC and equipment last longer, rather than have just 1x LF inverter that I have to rely on to survive.

I agree with all but the last line.

I'd rather be able to afford FOUR or more LF inverters to the two hf inverters (sol-ark's pricing). I'd buy two max giving 12k with 36kw surge vs a single sol-ark 12k and have money left over to buy batteries to make up for any extra draw or have 8 LF inverters for the same money with 32kw RAW power and 96 KW surge

Two each their own though. That's the beauty of the world at least right now we can all go with what we want and its all good.

 

[Warpspeed]

I personally would rather have 2x HF inverters that can start my offgrid AC and Well pump, and maybe even add in a SoftStart to make my AC and equipment last longer, rather than have just 1x LF inverter that I have to rely on to survive.

There is certainly merit in having a backup, no argument there.

The alternative is a very simple robust easy to fix LF inverter with enough spares to be able to repair anything that might fail.
These days almost everything is deliberately designed to be obsolescent, cheap, and unrepairable.

While having wifi, data logging, a graphics screen, sound effects, and internet connection may be nice, none of that is needed to turn dc into some usable ac.
These days when all the fancy technology stops working, its usually unrepairable, even by a professional.

 

[Hedges]

 

[Brucey]

You gotta think that most of the population is also grid tied, or at the very least grid assist. This is why I have 1x SolArk 12k (a 9kw HF inverter), and have no problem running my whole house, including a 5 ton AC, because the grid is there for my surge. And since the inverter is just pumping kWh's out and not getting the harsh surge, I expect it to last ATLEAST 5 years, and hopefully 10 or more.

The amount of people who are completely off-grid and need 50kW of LF surge capability are very few and far between. This is why companies are getting away from LF. Even newer appliances are needing less inrush current as the years go by, like inverter type mini-split air conditioners.

I think a lot of those folks running their big loads with grid available will prob be surprised if there's a grid outage and their inverters can no longer deliver what they thought they could. Because surely they also spent that money to also have the same experience when grid is offline? The grid goes out and no air conditioning? I guess as long as grid stays up all is good. But for some that understand the tech, they want the performance to power loads without relying on the availability of the grid. Grid is nice to have but full performance can be obtained without it.

 

[Warpspeed]

I think a lot of those folks running their big loads with grid available will prob be surprised if there's a grid outage and their inverters can no longer deliver what they thought they could.

Oh it goes way beyond that.
Wait until gasoline costs fifteen dollars a gallon, and people will be whining about not being able to aford to run their 800 horsepower sports truck.

 

[Brucey]

So another user reported their ACTUAL 5kva Victron Quattro idle consumption of 55w
That is a 120v 4k LF inverter with toroidal transformer
@HighTechLab mentioned a high sigineer idle consumption but I contend with the following:
To achieve the equivalent 12k inverter capacity, one would need 3 of the 5kva Quattro (ignoring the 3 phase instead of split phase issue).

3x55w=165w
What am I missing? That’s also excluding MPPT which is separate.

To be clear. I’m not contending that the sigineer/Growatt are nearly as efficient, robust, or reliable as the Victron.
But if the biggest qualm is idle consumption.
And 12k and LF, it sounds like it’s part of the territory

The newest Quattro II 5kVA (currently only in 240V) has a listed idle of 18W. I'm assuming the larger Quattro IIs to come will also have a significantly lower idle versus the Quattro I's.

 

[Lt.Dan]

I think a lot of those folks running their big loads with grid available will prob be surprised if there's a grid outage and their inverters can no longer deliver what they thought they could. Because surely they also spent that money to also have the same experience when grid is offline? The grid goes out and no air conditioning? I guess as long as grid stays up all is good. But for some that understand the tech, they want the performance to power loads without relying on the availability of the grid. Grid is nice to have but full performance can be obtained without it.

I won't be surprised. My SolArk 12k purposely doesn't power my main panel (where the AC or dryer are at), it only powers the sub panel in the garage, with the lights, outlets, kitchen, and garage etc, and then backfeeds the main panel. In the event of a power outage, I will have no A/C.

Knowing that, I also havent had a power outage that I have noticed in the last 10 years. I've only had solar for the last 3.

 

[OffGridForGood]

The Genetry Solar 12 kW idles at about 30 watts unloaded. There's a generally negative opinion about them, and in dealing with them I'd say it's earned. But not for the inverter. The inverter is 100% tank. Super solid machine and way under priced.

Interesting - I looked them up, Genetrysolar.com they spec the 12kW LF at 48W idle consumption - impressive for a 12k LF. I notice they offer the 12k in various voltage (customer can choose) 24, 36, 48 60 (TBD) - I don't think I can even imagine a 12k running 24v - likely they derate the output to hold the amperage to acceptable levels. Interesting to see 36-volt. They say US assembly.

At $2,999USD for the 12K - that is pretty solid value. List at 111 pounds, 125 shipping weight (ok must be LF)
Which model are you running?
Do you pair up two inverters or run a single?
How long have you been operating it - what loads do you handle with it?

 

[CoolWill]

Interesting - I looked them up, Genetrysolar.com they spec the 12kW LF at 48W idle consumption - impressive for a 12k LF. I notice they offer the 12k in various voltage (customer can choose) 24, 36, 48 60 (TBD) - I don't think I can even imagine a 12k running 24v - likely they derate the output to hold the amperage to acceptable levels. Interesting to see 36-volt. They say US assembly.

At $2,999USD for the 12K - that is pretty solid value. List at 111 pounds, 125 shipping weight (ok must be LF)
Which model are you running?
Do you pair up two inverters or run a single?
How long have you been operating it - what loads do you handle with it?

I have two 12 kW installed on separate systems in the same building. 48 volts. These were desired by the customer and I installed them. They are NOT UL listed, so that may be a non-starter for some people. I have over 500 kWh through one of them so far with over 1000 hours of uptime. They start a 1 HP well pump no problem. They start a 4 ton A/C no problem. I have no complaints about the hardware.

But the business side is bad. It's just a two man operation and they are struggling to meet demand. It took 4 months to get these inverters. I'm still waiting on a 6 kW.

 

[SupraSPL]

Hopefully we will get away from single phase AC motors as much as possible, but it would be sad to see LF inverters less available.

I replaced a 1/2 HP Goulds jet pump (1350VA before inverter losses) with a 12V 260W RV pump and it does the same job in the same time frame, about 45 seconds to pull 2.5 gallons from a shallow sand point and into the pressure tank. 6X less watt hours not to mention no massive startup spike. I had a separate 3000W HF inverter on standby just for that pump, now it's a backup inverter.

I cool the house with a pair of Midea U 8000 BTU window units that are inverted DC, have no startup spike and really sip power. They are incredible dehumidifiers on dry mode. Paid $150ea on FB market.

Window fans (100W) and inline fans (200W) can now be replaced with $65 inverted or direct DC inline fans that pull 65 watts max. Same goes for washing machines, fridges, dehumidifiers, vacuums, ceiling fans, power tools and furnace blowers. This really is some game changing tech.

95% of the time I run the house on a 120V 3500W HF inverter with 6 watt standby power...until the GF comes over then I might fire up the LF ?

 

[OffGridForGood]

I have two 12 kW installed on separate systems in the same building. 48 volts. These were desired by the customer and I installed them. They are NOT UL listed, so that may be a non-starter for some people. I have over 500 kWh through one of them so far with over 1000 hours of uptime. They start a 1 HP well pump no problem. They start a 4 ton A/C no problem. I have no complaints about the hardware.

But the business side is bad. It's just a two man operation and they are struggling to meet demand. It took 4 months to get these inverters. I'm still waiting on a 6 kW.

Interesting,
I haven't seen any other 12k sized 120/240 true-LF units anywhere close to this price point, with such low Idle current.
I will put them on my 'watch list' for the future 24kW system design.
Do you have the manual for the 12k? I didn't see a link to manuals on their site.
If anyone has a pair of these running together I would like to know how this worked out.
Did you connect the Genetry to Solar Assistant?
Were the installs you did using RS-232 or 485 or CAN comms?

 

[Hedges]

Genetry Solar 12KW Inverter – Genetry Solar

www.genetrysolar.com

"12,000W
Split Phase: 240v @ 50A (or 120v @ 50A from both L1-N and L2-N)
Single Phase: not supported. (The transformer can physically do 120v
single-phase, but none of the AC output circuitry is rated for 100A)NOTE: Inverter alarms are based on amperage, not wattage"

OK, how much 120V single phase current CAN it do?
Oh, I think it means 50A on L1, 50A on L2, 50A on N.
Surge wattage may be available at 120V (double current), but steady state 6000W not 12000W on one phase.

"

Transfer Efficiency	99% (yeah, the competition always lists this useless spec!)
AC Charge Efficiency	~72% (wonder why the competition never lists this!)
Maximum Charge Current	approx. 120A @ 48v

"

120A x 48V x (1 - 72%) = 1612W dissipated by inverter when charging?
72% is more like expected round-trip efficiency with lead-acid battery.

 

[Hedges]

$3000 for that 12kW inverter.

Consider Sunny Island new liquidation on eBay $2000 each, pair for $4000

SMA Sunny Island Off-Grid Inverter (SI6048-US-10) for sale online | eBay

Find many great new & used options and get the best deals for SMA Sunny Island Off-Grid Inverter (SI6048-US-10) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Or used $1200

SMA Sunny Island Off-Grid Inverter (SI6048-US-10) for sale online | eBay

Find many great new & used options and get the best deals for SMA Sunny Island Off-Grid Inverter (SI6048-US-10) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Another used one for $1750, so a pair (used) same price as Gentry (new)

SMA Sunny Island Off-Grid Inverter (SI6048-US-10) for sale online | eBay

Find many great new & used options and get the best deals for SMA Sunny Island Off-Grid Inverter (SI6048-US-10) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[OffGridForGood]

$3000 for that 12kW inverter.

Consider Sunny Island new liquidation on eBay $2000 each, pair for $4000

SMA Sunny Island Off-Grid Inverter (SI6048-US-10) for sale online | eBay

Find many great new & used options and get the best deals for SMA Sunny Island Off-Grid Inverter (SI6048-US-10) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Or used $1200

SMA Sunny Island Off-Grid Inverter (SI6048-US-10) for sale online | eBay

Find many great new & used options and get the best deals for SMA Sunny Island Off-Grid Inverter (SI6048-US-10) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Another used one for $1750, so a pair (used) same price as Gentry (new)

SMA Sunny Island Off-Grid Inverter (SI6048-US-10) for sale online | eBay

Find many great new & used options and get the best deals for SMA Sunny Island Off-Grid Inverter (SI6048-US-10) at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Don't worry, the SMA are also on my watch list!
Maybe when you get some new units you can sell me (for cheap!) your current 24kW set up!

 

[Hedges]

My dozen Sunny Island are MINE! ALL MINE!
Also my 20 sunny boys and 2 Sunny Island Chargers.

I have 7 SI running, plan 2 more for my new house. Could loan one to my sister. Considered power for my mountain property but they might grow legs. Spares is good (and with 4x in one system, that's a couple hot spares.)

That used one for $1200 matches lowed price I paid (for new in the box.)
From DC Solar auction, I think some people bought (5048 or 6048?) for $600 or less.
When $5750 MSRP, $4750 street price Sunny Islands were all over eBay for $1700, some people said, "But I can get a Growatt for $1200!

Main limitation of Sunny Island is it doesn't have peak shave and time shift features (although it can do some time based connect to generator or grid.) Also doesn't have latest required features so not allowed as an exporting inverter for new net-metering installs, just a UPS/island grid.

But I think it is among the best battery inverters for medium to large installs. At the smaller end, for off-grid, 1x SI and an auto-transformer to make 120/240V split phase would support 12kW of Sunny Boy. Add DC coupled PV with communication or a shunt, if desired.

 

[OffGridForGood]

My dozen Sunny Island are MINE! ALL MINE!
Also my 20 sunny boys and 2 Sunny Island Chargers.

No wonder the prices stay high on these!
I sure like the SMA build quality, the price for a new one in my market in 2021 was over $5,000 so I passed and bought the first MPP 6048 as a toy/pet project (that grew) LOL. Really I just wanted better emergency lights in the shop for power outages! Well that is where this addiction hobby started. Now I have this 'on site power plant', that supplies my business electrical needs 100% 24/7 and most of my home (next door) and we use an EV for any excess during summer.
With the third MPP unit installed, we are at our production limit of 19.6kW, but this is not top tier equipment, so we target 16kW as max other than starting currents.
I feel we will outgrow the 16kW limit, and I am looking at options for 24kW, and higher quality equipment, with lower idle consumption.
My ideal solution would be a 24kW unit (pair of 12kW) with 100W or less idle, about $8,000USD range price point. A lot of bells and whistles are not needed. I have about two years for planning, see what the market does. The EG4 18kpv caught my eye. Would like to see what else comes along.

 

[solar8484]

The Genetry Solar 12 kW idles at about 30 watts unloaded. There's a generally negative opinion about them, and in dealing with them I'd say it's earned. But not for the inverter. The inverter is 100% tank. Super solid machine and way under priced.

I think the jury is still out regarding the GS inverters as there are reports that they can't run some loads like certain washing machines. Also, they use aluminum transformer windings to reduce weight but I wonder about the durability vs copper.

 

[Hedges]

"12,000W
Split Phase: 240v @ 50A (or 120v @ 50A from both L1-N and L2-N)
Single Phase: not supported. (The transformer can physically do 120v
single-phase, but none of the AC output circuitry is rated for 100A)NOTE: Inverter alarms are based on amperage, not wattage"

OK, how much 120V single phase current CAN it do?
Oh, I think it means 50A on L1, 50A on L2, 50A on N.
Surge wattage may be available at 120V (double current), but steady state 6000W not 12000W on one phase.

But I think 36kW surge into transformer means 120V at 300A, enough to start a 7kW 120V induction motor (assuming 1 second or longer surge is delivered.)

That should handle everything that ought to be on 120V and more.

Sunny Island, 11kW surge available at 120V (unless you parallel two.)

I think the jury is still out regarding the GS inverters as there are reports that they can't run some loads like certain washing machines. Also, they use aluminum transformer windings to reduce weight but I wonder about the durability vs copper.

Aluminum is the norm in transformers for use on grid above about 10kW.
Problem is if aluminum overheats, but transformers are designed to run up to about 200C. An inverter has better chance to monitor and shut down, vs. something only protected by a breaker.

I get copper when I can.

 

[OffGridForGood]

I think the jury is still out regarding the GS inverters as there are reports that they can't run some loads like certain washing machines.

A washing machine is a pretty light load in my world, the Dryer on the other had, yeah, nothing like starting up a 120v motor and a 240v heating element simultaneously...only my big air compressor is more demanding than the Dryer. In fact I pay attention to avoid cycling the compressor and the dryer at the same time if possible.
If the GS inverters have trouble with the washing machines, I wonder if that issue is about how 'clean' the power is for the electronics, rather than the total load involved. That seems like a big red flag to me.