edrivas411
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With high frequency inverters pushing more power and low frequency dropping in price, which would be better for an all electric house? Reminded that surge loads are high in a all electric house.
Low or high frequency inverter
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timselectric
If I can do it, you can do it.
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Either are fine. The surges come from inductive loads (motors). It doesn't matter if your heat source is electricity or gas, the motors are the same.
wpns
Solar Joules are catch and release
Ford or Chevy? Doesn’t matter, just pick a good one with decent service and warranty and build in some redundancy.
edrivas411
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Does one outlast the other since the transformer can take the hit from a surge better than a Moffett? As for cost, the difference isn't much until you start calculations for surges. Can the grid boss be used with low frequency inverter to eliminate additional equipment?
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timselectric
If I can do it, you can do it.
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Not anymore. HF has come a long way. LF is definitely on its way out.
Brucey
Velcro Man
Do you have unbalanced loads?
wpns
Solar Joules are catch and release
18Kpv will support 8KW on any one line with a total of 12K, how unbalanced are your loads?
RCinFLA
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In real world utility there is a term called system 'inertia'. This is the angular momentum of alternator rotors that can source or sink AC power with angular momentum. This helps the grid absorb positive or negative surge power. This includes what comes with poor power factor loads. It helps keep the utility grid stable.
HF inverters have little to no 'inertia'. What little inertia they provide comes from their HV DC filter capacitors. AC motor startup surge current is not the only consideration. Poor power factor inductive loads have a negative power flow for a portion of the AC cycle.
With poorer ability of HF inverters to absorb the momentary power back push, the result is spiking of the HV DC voltage or high ripple voltage on the HV DC bus. This is hard on the HV DC bus filter capacitors which have electrolytic type capacitors with ESR (effective series resistance) that heats the HV DC capacitors when there is a lot of AC ripple current. It can also result in battery to HV DC converter load instability.
HF inverters like Sol-Ark, Deye, and EG4 have a large bank of HV DC capacitors to improve the HF inverter's inertia.
LF inverters inherently have instantaneous bi-directional power flow capability, with back push power surges being pushed directly to batteries. This makes them have the appearance of strong 'inertia', assuming the battery is not at full state of charge where any back push can cause inverter DC input voltage to rise beyond maximum limit, causing inverter to shut down.
A lot of what the new regulations like Cal Rule 21 have to do with renewable energy systems feeding the grid providing a synthetic 'inertia' to the utility grid system.
HF inverters have little to no 'inertia'. What little inertia they provide comes from their HV DC filter capacitors. AC motor startup surge current is not the only consideration. Poor power factor inductive loads have a negative power flow for a portion of the AC cycle.
With poorer ability of HF inverters to absorb the momentary power back push, the result is spiking of the HV DC voltage or high ripple voltage on the HV DC bus. This is hard on the HV DC bus filter capacitors which have electrolytic type capacitors with ESR (effective series resistance) that heats the HV DC capacitors when there is a lot of AC ripple current. It can also result in battery to HV DC converter load instability.
HF inverters like Sol-Ark, Deye, and EG4 have a large bank of HV DC capacitors to improve the HF inverter's inertia.
LF inverters inherently have instantaneous bi-directional power flow capability, with back push power surges being pushed directly to batteries. This makes them have the appearance of strong 'inertia', assuming the battery is not at full state of charge where any back push can cause inverter DC input voltage to rise beyond maximum limit, causing inverter to shut down.
A lot of what the new regulations like Cal Rule 21 have to do with renewable energy systems feeding the grid providing a synthetic 'inertia' to the utility grid system.
Quattrohead
Emperor Of Solar
Just choose the 12000 xp, 18K PV or Flexboss and don't worry about it, they can all handle this. I personally am running a pair of 18K PV for an all electric house in Florida, don't even think about the inverters anymore.
42OhmsPA
Who likes Electrical Gremlins?
edrivas411
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Thank you. I was wondering why everything was going high frequency.
edrivas411
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Thank you. Clears up my concerns of spending money to have to use a warranty. I prefer to have a warranty and never use it.
JerryK
Solar Enthusiast
Cheaper to build = higher profit margins....
edrivas411
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Good to hear. Thank you.
Just saw this, actually just testing the Power Pro indoor battery, but they were using the 18k PV to put the loads on it. screen on the 18K does not show it but I bet the data graphs caught it.
base load of 195 amps on the battery and 18 K outputting ~10KW.
Then they started that IR bellt drive compressor on top of the existing load, surging the single Power Pro battery and 18Ks abilities.
Not bad. Not bad at all.
base load of 195 amps on the battery and 18 K outputting ~10KW.
Then they started that IR bellt drive compressor on top of the existing load, surging the single Power Pro battery and 18Ks abilities.
Not bad. Not bad at all.
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More to add on the video above, versus my own test experience today with my air compressor.
Was wiring a disconnect input for the 18K from grid so the 18K can be taken out of the circuit, so it seemed like a good time to test whether the 18 K could handle the 80 gallon belt drive after being impressed by the video.
My results do not match the test they did above.
Had about a 3000 watt load on the 18K- with an additional 2KW coming in from PV, ( versus their 195 amps battery current draw already to support their existing loads with only one Power Pro, before they were able to successfully start the belt drive IR compressor)
I tried to start the 80 gallon two stage (6 hp start)- 5 HP running compressor and the compressor maybe rotated 1 revolution then Moaned and lights out.
The 18k shut down.
I immediately shut off the pressure switch on the compressor.
18K and lights came back up in about 5 seconds.
Now I have my answer, as far as ever running this compressor "Off Grid" without a soft start or adding another 18K PV the answer is no.
Was wiring a disconnect input for the 18K from grid so the 18K can be taken out of the circuit, so it seemed like a good time to test whether the 18 K could handle the 80 gallon belt drive after being impressed by the video.
My results do not match the test they did above.
Had about a 3000 watt load on the 18K- with an additional 2KW coming in from PV, ( versus their 195 amps battery current draw already to support their existing loads with only one Power Pro, before they were able to successfully start the belt drive IR compressor)
I tried to start the 80 gallon two stage (6 hp start)- 5 HP running compressor and the compressor maybe rotated 1 revolution then Moaned and lights out.
The 18k shut down.
I immediately shut off the pressure switch on the compressor.
18K and lights came back up in about 5 seconds.
Now I have my answer, as far as ever running this compressor "Off Grid" without a soft start or adding another 18K PV the answer is no.
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Have you measured the inrush current on the 80 gallon compressor before when it was wired into grid power?
No I actually haven't, I do not have an inductive current meter that can catch and save a surge reading, but do have regular AC and DC inductive current ability on the meters. I will see what it shows.
Also in the 18K's defense- this compressor is marketed as a five HP (running) compressor the motor is actually a 6 HP / 24 amp unit.
After watching that video (starting their ("massive") compressor, was thinking maybe there is a chance... but knew there was also a good chance it would not. I do have a feeling that the two Schneider XW Pro 6848 Low Frequency transformer inverters in parallel I bought wouldn't flinch doing the same test.
I really do like the 18k PV, but as others have said, large inductive loads and or load imbalance are HF inverters nemesis when it comes to their perceived ratings.
Luckily our grid overall is pretty stable and the chances I would need to pump up the large compressor with grid down are slim anyway. I am always impressed when there is a lot of solar incoming and the 18K can be charging the batteries at 12KW and also knocking the grid use down by a few KW at the same time.
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It will be interesting to see.
I may have to get an insight home unit on the way, so I can at least test the 2 XW's in parallel to see how they do at starting this compressor.
fatjay
Solar Wizard
18k HF, don't' want to worry about surge? Just get way more than you need.
ksmithaz1
Solar / EV Junkie
To be in the lanfills or to NOT be in the landfills?
ksmithaz1
Solar / EV Junkie
If I had to do it today. . . 2 12000xp's, pretty sure it would start your motor. That being said, . . . I'd soft start it or replace it with something more inverter friendly.
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