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

Cduck28z

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Hey guys,
I've been in contact with Sigineer Power about their HS10048D IP65 outdoor AIO 10kW inverter. I will be powering most of my home with the unit including our 5ton AC unit. LRA on the unit is 127a but I'm expecting to get that down to 55a+/-5 with the EasyStart Micro-Air 368 Advanced Soft Starter (ASY-368-X72-BLUE) which should bring my peak load down closer to 14kW.

It appears that a lot of the AIO inverters on the market are High Frequency
- HS10048D
- LVX6048WP
- LV6048
- 6500EX-48
- Any of the Sol-Ark (5,8,12kW)

As apposed to some of the low frequency inverters I've been looking at
- LVX6048
- SPF12000TDVM
- M12048D

Snippets from my email with Sigineer Power:
Sigineer Power said:
-To be frank, the HS10048D is not the best option for you. It is a transformerless on and off grid solar inverter, mainly for on grid system. For off grid, you can have a look at our M12048D. It will continue to provide power from the grid to my panel even after my batteries are drained, as it will transfer to the AC input.

-The problem is, the HS10048D is high frequency inverter, it is less reliable in powering up inductive loads.

-Because the HS10048D inverter is transformerless, it is not designed to power inductive loads with motors.

-For the M12048D, there is a big transformer. It is 36KW surge for 5 seconds, while the HS10048D has only 20KW surge for 5 seconds. The HS10048D can handle a smaller inductive load around 4HP/3KW. Pls find this link below:
https://www.sigineer.com/news/high-...re-sine-wave-inverter-difference-explanation/

As state above, I'm expecting my AC to peak less than 14kW and once powered on should consume aprox 4.8kW sustained. A lot of the most popular AIO inverters are High Frequency Transformerless. How important is it to use the correct family of transformer (high vs. low freq) for to power devices like your air conditioning or shop air compressors with large motors like that?
 
It is 100% true that LF transformer units handle inductive loads better.
My 3 ton AC unit seems to be a bugger to start sometimes, almost like its locked up. The SPF6000T managed it most of the time with a growl, but the Sol-ark 12k (really 9k) has really struggled to start it.
With either unit, I had to connect the compressor back to utility to give it a kick up the arse !!!
 
Most modern inverters are high frequency; however, high frequency (HF) is used in place of "transformerless" to the consumer. Low frequency (LF) has come to mean, "big fat transformer that weighs a shitload and has true 2-3X, 20-30 second surge capability"

IMHO, you can't count on a HF inverter to provide any surge load for more that a few sine wave cycles (20-60ms). They are horrible for surge loads like electric motors.

Even at the reduced 55A, I would not expect the Sigineer to start the compressor.
 
All inductive loads are "harsh and nasty" AC fridges, compressors (all forms) and such have variable hard surge starts, some of which can last up to 60 seconds. Also other loads are still there and switching on/off randomly & concurrently... Ie big AC starting & freezer decided to start. This creates an exponential load and Eats FETS in a blink.

Low frequency with Supercaps & torrodial transformers don't even blink at such, the instant reserve response just handles it cleanly and is NO stress for them... I've pushed LF to edges with MIG welders and no blip.

Sigineer is Well regarded too, good company.

HF is for lighter and back supported use (ie grid power) that can take the surge.... Much cheaper and far easier to flog at unaware folks. Not appropriate for off-grid!!!!!!

Hope it helps.
 
HF is for lighter and back supported use (ie grid power) that can take the surge.... Much cheaper and far easier to flog at unaware folks. Not appropriate for off-grid!!!!!!
Sol-Ark seems to be the top of the top for industry standard, functionality, and build quality. But they also advertise as transformerless inverters. Would you say the statement above is applicable or does Sol-Ark 15kW system (12kW AC output) use such quality components that it is able to handle the full load of my 5 ton Air Conditioner (with soft start) along with several rooms?
 
(Just a few of my questions guys, sorry...)

What's a good surge protector brand to buy if I'm stuck with an HF inverter?

Also is there a DC surge protector? My 12v battery bank can't handle the start-up of my computer (850w PSU, 80% rated), although the SNADI toroidal inverter (12v 3000w) handles it well. The BMSes are replaceable but I don't want to do it right now (nor replace the PSU).
 
(Just a few of my questions guys, sorry...)

What's a good surge protector brand to buy if I'm stuck with an HF inverter?

Also is there a DC surge protector? My 12v battery bank can't handle the start-up of my computer (850w PSU, 80% rated), although the SNADI toroidal inverter (12v 3000w) handles it well. The BMSes are replaceable but I don't want to do it right now (nor replace the PSU).
That isn't what a surge suppressor does. Your only solution with an HF inverter is to de-rate it to handle the inrush.
 
Sol-Ark seems to be the top of the top for industry standard, functionality, and build quality. But they also advertise as transformerless inverters. Would you say the statement above is applicable or does Sol-Ark 15kW system (12kW AC output) use such quality components that it is able to handle the full load of my 5 ton Air Conditioner (with soft start) along with several rooms?
You can only find out by trying that combination, there is no way to know for sure. It seems like it should, especially with a soft start.
Those Sol-ark bashing tests are bollocks, loading up 1 leg to max and then wondering why the inverter is protective of its self.
 
There's a reason why I went with LF. I may not have a well pump, but I have other stuff that I want to be able to run and if things concurrently start up I don't want the inverter gagging if I'm running solely off solar due to a grid down situation.
 
(Just a few of my questions guys, sorry...)

What's a good surge protector brand to buy if I'm stuck with an HF inverter?

Also is there a DC surge protector? My 12v battery bank can't handle the start-up of my computer (850w PSU, 80% rated), although the SNADI toroidal inverter (12v 3000w) handles it well. The BMSes are replaceable but I don't want to do it right now (nor replace the PSU).
An Autotransformer might be the only saving grace for a HF inverter under the large loads. But with the added costs you might as well have gotten a LF in the first place.
 
Sol-Ark seems to be the top of the top for industry standard, functionality, and build quality. But they also advertise as transformerless inverters. Would you say the statement above is applicable or does Sol-Ark 15kW system (12kW AC output) use such quality components that it is able to handle the full load of my 5 ton Air Conditioner (with soft start) along with several rooms?
It can easily handle that
 
Hey guys,
I've been in contact with Sigineer Power about their HS10048D IP65 outdoor AIO 10kW inverter. I will be powering most of my home with the unit including our 5ton AC unit. LRA on the unit is 127a but I'm expecting to get that down to 55a+/-5 with the EasyStart Micro-Air 368 Advanced Soft Starter (ASY-368-X72-BLUE) which should bring my peak load down closer to 14kW.

It appears that a lot of the AIO inverters on the market are High Frequency
- HS10048D
- LVX6048WP
- LV6048
- 6500EX-48
- Any of the Sol-Ark (5,8,12kW)

As apposed to some of the low frequency inverters I've been looking at
- LVX6048
- SPF12000TDVM
- M12048D

Snippets from my email with Sigineer Power:


As state above, I'm expecting my AC to peak less than 14kW and once powered on should consume aprox 4.8kW sustained. A lot of the most popular AIO inverters are High Frequency Transformerless. How important is it to use the correct family of transformer (high vs. low freq) for to power devices like your air conditioning or shop air compressors with large motors like that?
I'm running two LV6548s which are HF, combined 26kW surge. As long as you have enough battery capacity couple with the MicroAir you'll be fine IMO. I have a 5 ton Trane with the Micro Air and it dropped my start current down to around 45A. That AC without the MircoAir one grid power would dim the lights a little. Now even on battery I'll just see a sub second flicker on LED bulbs when the AC starts.

So yeah, I'm not sure what the surge rating on the Sigineer is, but you definitely need to make sure you're not pulling more than your batteries can support. What are you looking at for battery capacity?
 
LF Inverters are on there way out over the long term. I would be surprised if in 5 years time you can find them.
It's not that they are not great at handling large inductive loads, the problem is the cost of those huge transformers. It's not just a disadvantage for the manufacturer in terms of cost to buy them, but it also hurts them along every part of the transportation route as well as system layout (Heavier steel case, much bigger size etc.) and even creates more expensive packaging. When your talking over 140lbs of Raw material vs 70lbs your at a huge disadvantage in material costs.

Also the typical consumer only cares about how many watts it is rated for.

I use to love the older 12V transformer based power supplies. They are super reliable and they deal with big loads a lot better than switching power supplies and they produce no RF noise. Unfortunately the reality is that very few companies make them anymore because nobody wants to deal with a 20lb power supply when they can make a 4lb one that handles the same amount of current.
 
Surge specs mean nothing without also specifying time length. Most AC PSC motors take about 0.4 to 0.5 seconds to spin up and have high surge current for close to that period of time. So look for surge current out to 500 msecs.

Many HF inverters don't spec surge time or have something like 1-5 msecs which is close to worthless.

On HF inverter, surge capability depends on how much HV DC filter capacitor storage they have to supply the surge current. Deye and SolArk have a large bank of HV DC capacitors. They take up about 15 times the area in the inverter compared to most low cost HF inverters.

Deye HV DC filter caps.jpg
 
Surge specs mean nothing without also specifying time length. Most AC PSC motors take about 0.4 to 0.5 seconds to spin up and have high surge current for close to that period of time. So look for surge current out to 500 msecs.

Many HF inverters don't spec surge time or have something like 1-5 msecs which is close to worthless.

On HF inverter, surge capability depends on how much HV DC filter capacitor storage they have to supply the surge current. Deye and SolArk have a large bank of HV DC capacitors. They take up about 15 times the area in the inverter compared to most low cost HF inverters.

View attachment 108983
No wonder the sol-ark surge specs are actually decent compared to other HF inverters
 
Surge specs mean nothing without also specifying time length. Most AC PSC motors take about 0.4 to 0.5 seconds to spin up and have high surge current for close to that period of time. So look for surge current out to 500 msecs.

Many HF inverters don't spec surge time or have something like 1-5 msecs which is close to worthless.

On HF inverter, surge capability depends on how much HV DC filter capacitor storage they have to supply the surge current. Deye and SolArk have a large bank of HV DC capacitors. They take up about 15 times the area in the inverter compared to most low cost HF inverters.

View attachment 108983
What Inverter Capacitor Bank is that Picture from?
 
It is from Deye 8k. SolArk is similar. Other big thing is the large amount of HV DC caps covers the momentary dropout of battery to HV DC converter when it makes mode change from buck to boost or boost to buck. This gives AC input load shaving feature that cheaper HF inverters do not have. It gives the converter the operational appearance of being instantly bi-directional on the fly.

On the Deye and SolArk, for 240/120vac split phase models, there are two independent HV DC buses. One for each of the 120vac inverters that are connected in series for 240vac.

The PV input power must be shared between these two independent HV DC buses, so there is an extra intermediate forward converter between PV SCC outputs and HV DC buses. It provides PV power sharing and isolation between the two HV DC buses and PV inputs. It also allows PV input voltage to be up to 500 vdc with the two HV DC buses being only about 250 vdc. The intermediate PV converter steps-down the 500vdc SCC boost converter output to 250vdc for HV DC buses. Downside is there is a couple of percent extra power loss on PV converter path to HV DC buses.

The filter caps in picture are each 1000 uF at 315 vdc max working voltage for the 250-300vdc buses.
 
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As apposed to some of the low frequency inverters I've been looking at
- LVX6048
- SPF12000TDVM
These are not low frequency. As sunshine_eggo mentioned, these are mis-labeled and are actually high frequency with a big fat transformer. I have two of the LVX6048 and can confirm the big fat transformer part.
 
It is 100% true that LF transformer units handle inductive loads better.
My 3 ton AC unit seems to be a bugger to start sometimes, almost like its locked up. The SPF6000T managed it most of the time with a growl, but the Sol-ark 12k (really 9k) has really struggled to start it.
With either unit, I had to connect the compressor back to utility to give it a kick up the arse !!!
is it possible to wire the sol-ark with grid assist where both the grid and inverter power the load at the same time so there is never any worry about starting current?
 
is it possible to wire the sol-ark with grid assist where both the grid and inverter power the load at the same time so there is never any worry about starting current?
I have gotten mixed reports on load shaving on SolArk. Some models appear to have the feature, some do not. I was told on a 15k that future FW release will have it. All models should be able to do load shaving.

The SolArk's and Deye HF inverters have a massive HV DC capacitor bank to allow battery to HV DC converter to switch from charging battery to supplying power from battery. This mode change needs to be near instantaneous for load shaving. The battery to HV converter takes several milliseconds to make the changeover so the HV DC capacitors have be large enough to supply the power during the converter mode switching.
 
Many of us have installed Soft Starters on our Air Conditioning compressors with very good results. They are capable of reducing inrush by up to 70% without lowering starting torque or spin up time.

Edit: Make sure the 5 min compressor cycle delay on the condenser and/or thermostat are working properly.
 
is it possible to wire the sol-ark with grid assist where both the grid and inverter power the load at the same time so there is never any worry about starting current?
That is how the sol-ark works when connected to the grid. You only need to worry about starting loads when not connected to the grid.
 
That is how the sol-ark works when connected to the grid. You only need to worry about starting loads when not connected to the grid.
But it doesn't connect to the same panel as the grid correct? You have to run a line from the grid to grid input on solark and then power the main panel from the load output on the solark?
 
But it doesn't connect to the same panel as the grid correct? You have to run a line from the grid to grid input on solark and then power the main panel from the load output on the solark?
You can do that or power the main panel through the grid input with limit to home mode
 

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