Hi Engineer.. have followed you forever... thanks for your videos... what do you suggest as an alternate to this Sol-Ark, I'm a Schneider and Victron person but am researching these for a 43' toy hauler build I'm doing and was going to go Quattro 15k EU with an AT on the output for balance, I'm knowledgeable on the DC stuff but still learning about the AC side.... Do you have a fave that you'd recommend instead? Thank you again sir... you ARE a great asset to our community...
Ben another great video, I've only installed these on StorEdge inverters. I would have never thought to install it for your purpose. I'm installing one as a backup for my 110 vac, 3.6 kw inverter generator while my standby generator is being overhauled. So I can feed it to the house and at least put 3600 of power back into my batteries. Thanks again for the videos.
Ben, really miss your videos. You always have such great content. Hopefully you can make more videos and build your channel. I'd love to see you have a 100K subscribers.
My parent's have the original Sol-Ark 8K and we quickly discovered it's limitations with 120Vac loads. We fried a small 120/24Vac transformer that was powering a HVAC control relay when the dishwasher heating element came on; the SCR switching circuit for the heating element wreaked havoc with the Sol-Ark and it must have briefly over-voltaged. Short story long, I installed a 5kVa 240/120Vac transformer and connected the 120Vac output to a new panel dedicated to the dishwasher. Works great other than the 50 Watts of idle draw.
Yeah it is unfortunate. The Sol-Ark has definitely gotten better since the 8k in that respect. The autotransformer definitely helps a lot with unbalanced loads. I have used a 240-120/240 isolation transformer on the output of a straight 240v inverter with good success.
4th day totally off grid! 20,600pv, 132kwh lfe battery (3 out of 10 batteries hooked up, 7 to go), 10 bms's/six brands, two SA 12K's, 10k honeywell lp gen with 2-wire start(Does GWatt have that?), 400 gal lp. After getting all the settings correct, it works like a charm. it powers three heat pumps 5.5 tons (vs compressor on one, soft starts on two), 80 gallon electric water heater (4.5kw), dryer, washing machine, electric range, fans, lights, all electronics. Love it! A full 40 space main 200A breaker panel, 100A sub in garage with a lot of breakers. That's the key to having balanced loads. Lots of breakers. Always run two Sol/Ark's for totally off grid. My old power bills showed 40-70 kwh. More in winter due to hp's. I use wood burner below 30F, have all electric heaters on a toggle switch for disabling. Defrost thermostat on one hp has nc spst switch to disable during dry cold weather when defrost is usually not needed. The other two hp's have demand defrost, too much electronics to mess with.
Curious, what state are you in and what batteries did you go with? I'm in SW Washington and in the process of upgrading our system from 10.8pv and 21kwh lifepo4 batteries with one solark (that kept tripping when running normal household loads). We added another 4pv and 32 kwh in batteries and another solark. Are you running a autotransformer? How often are you having to run that generator? We are trying to go 100% off grid but have a long way to go, I'm afraid. We still need to address a generator purchase that makes sense as the one we have is a Champion from Home Depot. Pretty sure that's not going to work.
When using a transformer on a split phase output you can get all the L1+L2 power to a single phase if the transformer is rated for the total power you have for a single phase. So if you have an inverter rated for only 6kW on L1 and 6kW on L2 and that your inverter limit the power to 6kW on L1 or L2 it is now possible to get all that 12kW to L1 or L2 because the iron core of the transformer dont matter with that... the magnetic field of L1 +L2 input together can be used to output on a single phase. the only CONS is the efficiency loss and phantom power....
Is your post a response to my question above or how is what you are saying related to this video, sorry, am new to Sol-Ark and trying to decide if it can replace my Victron or Schneider equip, thanks
Relevant NEC on the use of AT's. Circuits Derived from Autotransformers. Feeders shall not be derived from autotransformers unless the system supplied has a grounded conductor that is electrically connected to a grounded conductor of the system supplying the autotransformer. This means so long as the supply power is the same grounding system, AT's are good to go. This has been a long conversation on the diy solar power forum.
Thanks for the video. I bought a solar edge auto transformer for a different purpose. I am a mobile DJ and some venues have a 240v receptacle but they are the kind that don’t have a neutral. I got the auto transformer to have a neutral allowing me to be on an isolated 24Ov circuit and make 120v. I wondered if I could use the auto transformer in parallel with the buildings neutral when available and I think you have answered that for me. Again thank you
you need to remove the neutral from the SOLARK to fully make the transformer do it's job.You need to make the SOLARK basically provide ONLY 240 v to the system
Great videos thank you for producing I'm very intuitive quick question for you I am running a grid-tie inverter on my main panel and I have a sub panel with a off-grid inverter growatt I am hooking a Auto Transformer to the subpanel to give me a neutral because the inverter does not have a neutral it's a 220 I have an AC coupling breaker between the main panel and subpanel if the off-grid inverter dyes I can flip the breaker on and feed the subpanel do you think it's okay to leave the neutral hooked up from main panel to subpanel along with an auto Transformer on the sub panel I believe the law of physics will follow the path of least resistance and go to the auto Transformer instead of the city neutral
Good video! Quick question- Is your Service panel bonded to Ground? Trying to get my head around the Neutral/Ground bond in relation to the floating neutral of the Autotransformer balancing L1 and L2.
Hi Dan, yes the neutral and ground are bonded in the main service panel. The autotransformer actually doesn't have a floating neutral like an isolation transformer does. It uses a common neutral for the input and output. If you were to feed a panel with an isolation transformer, you'd need a new neutral go ground bond as that's considered a separately derived system and neutral would have no reference to ground without that bond. With no reference to ground, you could touch a hot wire to ground and it wouldn't have a path back to the source, so wouldn't trip any breakers and cause very dangerous situation.
@@benssolarandbattery Thanks Ben! I am setting up my system and will use a Growatt SPF5000ES for my 10KW battery bank AC coupled to 3 Danfoss 3.8KW Grid tied with 10KW of panels on my shed with the same Autotransformer for the Neutral. That way I can use the Growatt as a UPS and drive the Grid Tied panels with it when power is out.
Hey Ben, I got a question about SolArk that’s kinda unrelated to this video. When the inverter is in line to home grid tie mode, does it send power (to the main panel) out of its grid input?
Yes, it does. You can use the CTs that come with it to limit the power that it pushed back to the grid side to prevent if from selling back to the grid as well.
Still wondering why you did this, was it for reduction of inrush for motor loads, balancing would require going through the trans not just hooking it across... fill us in man.. thank you..
I have a similar setup and my question is this: When the inverter is bypassing grid power, then the auto-transformer is in parallel with the grid transformer - although a much higher resistance path - So do imbalances on L1/L2 with all the houses behind the grid transformer also flow into your house on one side, through the autotransformer, and back out on the other side, while burning a little power in the transformer windings? I bet they do, albeit a small amount. You should turn off all your house power so it's just the grid to the autotransformer and see if there is any current through it.
I would have to wager that the higher impedance would mostly prevent it, but you're right, it definitely could happen, especially if there was an issue at the main transformer. I don't get a lot of opportunity to shut off power to my house, but next time I do, I'll definitely check! Very important to tie the autotransformer in with a breaker, just in case.
Victron has a 100amp autotransformer with a fan and breaker built in . Might be a another option with more capacity and less chance of tripping breaker. Don't know if it would balance better though without trying it.
So the Victron unit is more encompassing because it has a 100a pass through current, with that tied to the breaker that powers the autotransformer. It is about the same size autotransformer as the SolarEdge, but you run all of the current though it, so if it overloads only on the autotransformer side, everything shuts off. The fan is definitely a nice touch too.
In your scenario (grid-tie with battery backup), there is no advantage to adding the autotransformer and it actually introduces a couple issues. First issue is unnecessary idle draw - no big deal, but wasted power nonetheless. Second issue is that the neutral current will be split between the main conventional dual winding transformer from the grid tie power and the autotransformer. Depending on impedances, under phase imbalance conditions, you may draw power from the autotransformer and overload it. The street transformer can handle that more than 30A imbalance, the autotransformer cannot. You will see that auto transfer switches do not connect an autotransformer while the grid is active - only in backup mode for both these reasons. Same thing happens in the SolArk - until it switches to off-grid. If you only run off-grid, what you have done could help with surges for 120V heavy loads and supporting large loading differences between the two 120V phases. Otherwise, the autotransformer should really be disabled - switched with a contactor or something similar to only connect when grid down.
Good point Bill. I will most likely leave it off while I'm grid tied and only turn it on manually when I'm off grid. I figure worst case it will trip the breaker, nothing more. However you're right and it shouldn't be used and definitely isn't needed when grid tied. This is basically a proof of concept to help my off grid customers, but also myself when I do go off grid eventually. Thanks for the feedback!
@@benssolarandbattery It will be interesting to find some 120V loads that tripped the SolArk alone and see if that issue is indeed improved with the added auto-transformer. SolArk claims good surge performance, but you were certainly able to get it to trip. It really depends on the duration and magnitude of the surge, as high-frequency inverters can typically handle brief surges but not somewhat longer ones. May be a good followup to see if the auto-transformer helps.
@Bill Johnson What if the inverter only outputs 240v. Would it still be a bad idea to use the auto-transformer? He in the Philippines we have 240v/60hertz from the grid but I have some motors and things from the US that us 120v/60hertz and I would like to use them here. I don't know nearly enough about electricity. I think it's actually 230v/60 but as best I can tell it's close enough. I would like to connect a separate panel that the auto-transformer is connected too.
If this is true, how do LF inverters get away with it? They would have the same issue in passthrough mode. To prevent my autotransformers from becoming overloaded, I derated the breaker sizing for my AT's. 5kva == 20 amp breaker by my math.
I imagine to make this do something significant you'd have to overload one of the legs enough to cause it to fail to provide the desired voltage, in which case the autotransformer would try to help. Or you'd have to use the autotransformer neutral completely and not the solark one so that it would ballance both sides and L1 would always equal L2.
Ben, am I correct in assuming the auto transformer only assists with items that draw 220V of current? Also, the biggest benefit is assisting the surge of power that is required to start the motor of the item, such as a compressor, well pump, etc.? Once in a while, my wife has had complaints about getting her large hair dryer to start, which has been my only complaint about my Sol-Ark 12K.
Actually its the opposite. It's there to help with the 120v loads. It basically works in parallel with the Sol-Ark and balances out any 120v loads to a certain degree, allowing for more available power on each leg.
@@benssolarandbattery Then, by balancing the two, it would eliminate the problem that I am experiencing? I meant to say 120V. Gotta Typo I missed. My wife's hairdryer is 120V, not 220V
roughly how many Ah Capacity (20hr): 186 6 volt batteries will i need to pull the water up 400 feet on 2 hp 220 pump. so far i hav 7 100 watt panels and 4 Ah Capacity (20hr): 186 batteries. i figure im about 40% thare. dose that sound right?
I think I finally got it! Because the Sol-Ark 12K is a transformerless inverter it doesn't balance heavy lopsided loads on one leg. Adding the auto transformer helps stabilize the lopsided leg by adding more power to the opposite leg. What would happen if you paralleled each leg with an auto transformer, one connected to each side?
You need the autotransformer to be attached to both legs and neutral so it will balance out the neutral (120v) current using the opposite leg. I'm not sure that it would work with one on each leg separately.
I was wondering about using the autotransformer on the AC INPUT side. I have a Growatt 5000 and an auto transformer coming. I would like to be able to charge the batteries with my 2 Honda eu2200's in parallel, since I already have those. I figure I could run like 3500 to 4000w with the 2 generators. My question is could that transformer work the other way? Can you put in 120 and get 240 single phase out? I would love for you to dig into this. Im thinking if you land the AC input onto a breaker in a sub panel, which has 2 additional breakers (one for the auto transformer and a single pole 30 for the generators) What are your thoughts on this? Thanks Ray
Hi Ray, Yes, the autotransformer works both ways. The limiting factor here is the line in. I believe it would be rated for around half or 2.5kva compared to inputting 240v. I don't believe solaredge posts those specs, but it you look at other similar autotransformers such as the Outback unit, it should be listed and you can extrapolate.
Haha, not too many people notice that down there. It's connected to a single west facing panel that I have bolted to the side of my house over one of the mini split air conditioners. It just feeds into the sub panel and is AC coupled with the rest of the system in a grid outage.
Do you think i can use this transformer to regulate the incoming grid voltage to around 230v? my grid fluctuates from 207v to 230v and shuts the grid tie inverters. Any suggestions how to solve this problem on the cheap? thanks
No, this won't help with that. In some places your power company may be able to help, in others not. I don't know off hand of a product that would help but I'm sure they exist.
Hi Ben, solaredge seems to imply that the autotransformer is what supplants the grid feed for your solaredge inverter, when the grid goes down. where does your system derive the ac to connect to your solaredge inverter so the solaredge will make AC power? Is it your hybrid inverter output AC power that convinces the solaredge to turn on? thank you
The hybrid inverter tricks the SolarEdge into thinking the grid is present, so it powers up. You need to be able to handle everything it can output when it fires up. The Autotransformer is there to provide a neutral in their system, but not absolutely required in other systems.
interesting comment about needing to sink all the solaredge output. where do you put your solaredge inverter output if it happens to be making maximum power? I have two 7600 inverters in parallel so might need to put 13kw somewhere. thank you
@@benssolarandbattery Hi Ben, that makes sense if the solaredge inverters cant throttle, which I assume they cant since they are normally connected to the grids black hole. Is there a logic level input on the solaredge inverter I can tap into to shut down just one inverter ? An input I can use to switch one inverter off, leave the other solaredge on with the hybrid inverter connected, for the case when the grid is down but I want to charge a reasonable battery and run the house load? Maybe I can make a current monitor on the battery that selects the second inverter depending on which way/how much battery current is flowing? I appreciate you thoughts, thank you, Mark
@Mark Rowland you may be able to get them to throttle with a different grid profile that accepts freq/watt commands. (As the frequency goes up, the output goes down) You can also tie one to a contactor that is held closed by the grid. Grid goes down, that inverter shuts down even if it's combined with the same output as the other.
I have another brand auto-transformer and both this and the 120 to 240 wiring schemes are documented for it. I use it to get 240v for a deep well pump. It has too much idle draw to leave it on all the time, plus it hums. So I only turn it on when I need to run the pump.
If this autotransformer works in parallel with another one (installed in inverter), I suggest, that direct parallel connection of this new autotransformer to the inverter's autotransformer will improve balancing performance of new autotransformer. Because wiring resistance (from autotransformer to panel) can affect balancing performance. But, for full balancing performance of new autotransformer, its neutral must be isolated from inverter's neutral. I.e., this new autotransformer must originate its own 240/120 V branch circuit with its own neutral. But, in this case, we cannot ground this neutral, because, it will have connection to the inverter's neutral through grounding conductors. The only way to see full balancing is to use isolation transformer with 240 V primary and 120+120 split-phase secondary. Is this case, we can successfully ground this new neutral.
Would it be possible to just feed the Sol-rk in with 240v and not the nuetral? That way all of the 120v current would be balanced through the transformer. This should be possible as the Sol-Ark will run two wire 240v equipment so the nuetral from the Sol-Ark is not essential.
@@mendohomepower7492 Many inverters will not accept just l1 and l2 and function those need to sense the neutral connection at least to accept the grid power they need to.
@@teekay1785 That's why the auto transformer should connect to a second subpanel that is downstream from the first critical load panel. That way the Sol-Ark or other split phase inverters can operate 240v three wire loads in the in the first load panel and then the L1, L2 and ground can feed to the second load panel that carries the transformer connection with the 120v circuits. The only glitch could possibly be in the ground but it wouldn't be bonded in the second sub panel.
Question: viewing a signature solar video using european 240v with the solar edge transformer indicated that US split phase 240 volt appliances like HVAC units that only use 240v can be run directly from european style 240 v inverters that are not split phase. Do you know or have an opinion on whether or not this is true?
Yes, it will work perfectly*. The only difference between the US 240 and euro 240 is US 240 is 120v L1 and 120v L2 which equals 240v. Euro 240 is 240v L1 and N. Appliances don't care as long as they run on straight 240v. *If they need a neutral as well to operate (usually for a control circuit) they won't work.
@@benssolarandbattery Thats certainly what I thought but wasn't as confident as I wanted to be. I somehow thought that maybe the split phase sine wave pattern helped "push" a 240 v motor at 2 different points of a revolution etc.
@@mendohomepower7492 good point. All of the inverters I've worked with have that setting adjustable between 50 and 60hz, but definitely something to check for! Thanks for watching!
Well, you want to give the autotransformer some sort of overcurrent protection, so could move to the main panel. It's connected in parallel with everything else, wouldn't want to double tap the breaker in the Sol-Ark really.
So I am confused I thought you were feeding the SolArk by AC coupling the grid tied Solar Edge which should fix the problem of inductive loads on start up the transformer is now fed by the Solar Edge grid tie and then ac coupled to your critical loads panel thus taking the load before it is satisfied by the SolArk which will work when the sun shines. I have done similar with Sun grid ties to beef up the Enphase although I never run it through a transformer I use batteries to produce the Ac for the Sun grid ties then AC couple that to the critical loads panel. When you kill the grid doesn't it take 5 minutes for the Solar edge to meld with the sine wave of the SolArk.
I see a BIG problem with that if the breaker on the Autotransfomer trips you can have 220 applied to a 120 appliance if the two are imbalanced I would not like a breaker there at all due to that problem. This problem will happen if you are off-grid.
Charles, this would only happen with a 240v inverter with no neutral. My inverter has a neutral as well so no issue if the autotransformer breaker trips.
@@Labeeman when on grid, you're correct. It serves no purpose. When off grid its there to assist the inverter with heavy inductive loads that the inverter by itself was having issues with.
@@benssolarandbattery Then the inverter is not supplying a true split-phase and it is desirable to have the transformer like a low-frequency inverter with a transformer. There are inverters that that transformer is required for 120 service as they are 240 only with no center tap (neutral) think overseas.
@@benssolarandbattery Nice. I was expecting more draw (40-50W?) The more I think about this addition, I'm assuming you'd really only want to use this off-grid and honestly any serious problematic loads should probably be 240V anyway.
Would it be possible to just feed the Sol-ark in with 240v L1 and L2 and not the neutral? That way all of the 120v current would be balanced through the transformer. This should be possible as the Sol-Ark will run two wire 240v equipment so the neutral from the Sol-Ark is not essential. If you could try that you should get a completely balanced load on the Sol-Ark. This could possibly be accomplished through a second sub panel where only the L1 and L2 leads plus ground enter it from the Sol-Ark via the first load panel and the transformer is connected in the second load panel.
Yes, it absolutely would be possible, but then all of the neutral current would be running though the Autotransformer and then I have to be able to shut then entire system down if the Autotransformer trips off due to overload, otherwise I fry things. I prefer to leave it this way, as the Autotransformer will help the Sol-Ark but not entirely take over the 120v loads.
@@benssolarandbattery I think I'll try it that way on one of my systems. The Sol-Ark is really finicky with pumps and things that are 120v. It hits that 4800w per leg ceiling much too often for my liking and reboots the system. The folly of high frequency systems. I may need two auto-transformers to pull it off but I think it would be worth it to have the sol-ark just feed the grid, charge the batteries and take care of 240v loads. The load balancing of the 120v end would be perfect as well.
Thanks for sharing
Good job. It is a cool move. I wish you didn't have to do that. Transformerless inverters are super efficient but have their issues.
It would be interesting to see a scope on both legs before and after the transformer was turned on
Hi Engineer.. have followed you forever... thanks for your videos... what do you suggest as an alternate to this Sol-Ark, I'm a Schneider and Victron person but am researching these for a 43' toy hauler build I'm doing and was going to go Quattro 15k EU with an AT on the output for balance, I'm knowledgeable on the DC stuff but still learning about the AC side.... Do you have a fave that you'd recommend instead? Thank you again sir... you ARE a great asset to our community...
No shit....for a 7k inverter you shouldn't have to do anything. IMHO solark is really nice but they are over priced.
A very valuable test. Thank you for spending your money and time to answer this for us!
Ben another great video, I've only installed these on StorEdge inverters. I would have never thought to install it for your purpose. I'm installing one as a backup for my 110 vac, 3.6 kw inverter generator while my standby generator is being overhauled. So I can feed it to the house and at least put 3600 of power back into my batteries. Thanks again for the videos.
Ben, really miss your videos. You always have such great content. Hopefully you can make more videos and build your channel. I'd love to see you have a 100K subscribers.
My parent's have the original Sol-Ark 8K and we quickly discovered it's limitations with 120Vac loads. We fried a small 120/24Vac transformer that was powering a HVAC control relay when the dishwasher heating element came on; the SCR switching circuit for the heating element wreaked havoc with the Sol-Ark and it must have briefly over-voltaged. Short story long, I installed a 5kVa 240/120Vac transformer and connected the 120Vac output to a new panel dedicated to the dishwasher. Works great other than the 50 Watts of idle draw.
Yeah it is unfortunate. The Sol-Ark has definitely gotten better since the 8k in that respect. The autotransformer definitely helps a lot with unbalanced loads. I have used a 240-120/240 isolation transformer on the output of a straight 240v inverter with good success.
4th day totally off grid! 20,600pv, 132kwh lfe battery (3 out of 10 batteries hooked up, 7 to go), 10 bms's/six brands, two SA 12K's, 10k honeywell lp gen with 2-wire start(Does GWatt have that?), 400 gal lp. After getting all the settings correct, it works like a charm. it powers three heat pumps 5.5 tons (vs compressor on one, soft starts on two), 80 gallon electric water heater (4.5kw), dryer, washing machine, electric range, fans, lights, all electronics. Love it! A full 40 space main 200A breaker panel, 100A sub in garage with a lot of breakers. That's the key to having balanced loads. Lots of breakers. Always run two Sol/Ark's for totally off grid. My old power bills showed 40-70 kwh. More in winter due to hp's. I use wood burner below 30F, have all electric heaters on a toggle switch for disabling. Defrost thermostat on one hp has nc spst switch to disable during dry cold weather when defrost is usually not needed. The other two hp's have demand defrost, too much electronics to mess with.
Curious, what state are you in and what batteries did you go with? I'm in SW Washington and in the process of upgrading our system from 10.8pv and 21kwh lifepo4 batteries with one solark (that kept tripping when running normal household loads). We added another 4pv and 32 kwh in batteries and another solark. Are you running a autotransformer? How often are you having to run that generator? We are trying to go 100% off grid but have a long way to go, I'm afraid. We still need to address a generator purchase that makes sense as the one we have is a Champion from Home Depot. Pretty sure that's not going to work.
NICE thanks for sharing brother.
When using a transformer on a split phase output you can get all the L1+L2 power to a single phase if the transformer is rated for the total power you have for a single phase. So if you have an inverter rated for only 6kW on L1 and 6kW on L2 and that your inverter limit the power to 6kW on L1 or L2 it is now possible to get all that 12kW to L1 or L2 because the iron core of the transformer dont matter with that... the magnetic field of L1 +L2 input together can be used to output on a single phase. the only CONS is the efficiency loss and phantom power....
Is your post a response to my question above or how is what you are saying related to this video, sorry, am new to Sol-Ark and trying to decide if it can replace my Victron or Schneider equip, thanks
The auto transformer is a great way to balance 120v loads back to a 240v source. So in the case of a solark, it should balance the phases. Good idea!
Relevant NEC on the use of AT's.
Circuits Derived from Autotransformers. Feeders shall not be derived from
autotransformers unless the system supplied has a grounded conductor that is electrically
connected to a grounded conductor of the system supplying the autotransformer.
This means so long as the supply power is the same grounding system, AT's are good to go. This has been a long conversation on the diy solar power forum.
Thanks for the video. I bought a solar edge auto transformer for a different purpose. I am a mobile DJ and some venues have a 240v receptacle but they are the kind that don’t have a neutral. I got the auto transformer to have a neutral allowing me to be on an isolated 24Ov circuit and make 120v.
I wondered if I could use the auto transformer in parallel with the buildings neutral when available and I think you have answered that for me.
Again thank you
you need to remove the neutral from the SOLARK to fully make the transformer do it's job.You need to make the SOLARK basically provide ONLY 240 v to the system
Great videos thank you for producing I'm very intuitive quick question for you I am running a grid-tie inverter on my main panel and I have a sub panel with a off-grid inverter growatt I am hooking a Auto Transformer to the subpanel to give me a neutral because the inverter does not have a neutral it's a 220 I have an AC coupling breaker between the main panel and subpanel if the off-grid inverter dyes I can flip the breaker on and feed the subpanel do you think it's okay to leave the neutral hooked up from main panel to subpanel along with an auto Transformer on the sub panel I believe the law of physics will follow the path of least resistance and go to the auto Transformer instead of the city neutral
Good video! Quick question- Is your Service panel bonded to Ground? Trying to get my head around the Neutral/Ground bond in relation to the floating neutral of the Autotransformer balancing L1 and L2.
Hi Dan, yes the neutral and ground are bonded in the main service panel. The autotransformer actually doesn't have a floating neutral like an isolation transformer does. It uses a common neutral for the input and output.
If you were to feed a panel with an isolation transformer, you'd need a new neutral go ground bond as that's considered a separately derived system and neutral would have no reference to ground without that bond. With no reference to ground, you could touch a hot wire to ground and it wouldn't have a path back to the source, so wouldn't trip any breakers and cause very dangerous situation.
@@benssolarandbattery Thanks Ben! I am setting up my system and will use a Growatt SPF5000ES for my 10KW battery bank AC coupled to 3 Danfoss 3.8KW Grid tied with 10KW of panels on my shed with the same Autotransformer for the Neutral. That way I can use the Growatt as a UPS and drive the Grid Tied panels with it when power is out.
I think my dad would have begged to differ about working in a life panel. We used to joke around about that's how he kept re-energized
Please do an update video in the near future.
I will try to!
Try turning off all loads, then check amp draw through auto transformer. Let us know. Thank you.
It has an 18W idle draw.
Hey Ben, I got a question about SolArk that’s kinda unrelated to this video.
When the inverter is in line to home grid tie mode, does it send power (to the main panel) out of its grid input?
Yes, it does. You can use the CTs that come with it to limit the power that it pushed back to the grid side to prevent if from selling back to the grid as well.
To make it more balance on both leg you must remove the neutral from the 12k sol ark inverter..
7:25 "Good, nothing bad happened" 😂
Still wondering why you did this, was it for reduction of inrush for motor loads, balancing would require going through the trans not just hooking it across... fill us in man.. thank you..
So what is the reason for this. How will this help with motor loads?
I have a similar setup and my question is this: When the inverter is bypassing grid power, then the auto-transformer is in parallel with the grid transformer - although a much higher resistance path - So do imbalances on L1/L2 with all the houses behind the grid transformer also flow into your house on one side, through the autotransformer, and back out on the other side, while burning a little power in the transformer windings? I bet they do, albeit a small amount.
You should turn off all your house power so it's just the grid to the autotransformer and see if there is any current through it.
I would have to wager that the higher impedance would mostly prevent it, but you're right, it definitely could happen, especially if there was an issue at the main transformer. I don't get a lot of opportunity to shut off power to my house, but next time I do, I'll definitely check! Very important to tie the autotransformer in with a breaker, just in case.
Victron has a 100amp autotransformer with a fan and breaker built in . Might be a another option with more capacity and less chance of tripping breaker. Don't know if it would balance better though without trying it.
So the Victron unit is more encompassing because it has a 100a pass through current, with that tied to the breaker that powers the autotransformer. It is about the same size autotransformer as the SolarEdge, but you run all of the current though it, so if it overloads only on the autotransformer side, everything shuts off. The fan is definitely a nice touch too.
@@benssolarandbattery Oh yeah , I see what you mean , That would make David's problem go away as well.
In your scenario (grid-tie with battery backup), there is no advantage to adding the autotransformer and it actually introduces a couple issues. First issue is unnecessary idle draw - no big deal, but wasted power nonetheless. Second issue is that the neutral current will be split between the main conventional dual winding transformer from the grid tie power and the autotransformer. Depending on impedances, under phase imbalance conditions, you may draw power from the autotransformer and overload it. The street transformer can handle that more than 30A imbalance, the autotransformer cannot. You will see that auto transfer switches do not connect an autotransformer while the grid is active - only in backup mode for both these reasons. Same thing happens in the SolArk - until it switches to off-grid.
If you only run off-grid, what you have done could help with surges for 120V heavy loads and supporting large loading differences between the two 120V phases. Otherwise, the autotransformer should really be disabled - switched with a contactor or something similar to only connect when grid down.
Good point Bill. I will most likely leave it off while I'm grid tied and only turn it on manually when I'm off grid. I figure worst case it will trip the breaker, nothing more. However you're right and it shouldn't be used and definitely isn't needed when grid tied. This is basically a proof of concept to help my off grid customers, but also myself when I do go off grid eventually.
Thanks for the feedback!
@@benssolarandbattery It will be interesting to find some 120V loads that tripped the SolArk alone and see if that issue is indeed improved with the added auto-transformer. SolArk claims good surge performance, but you were certainly able to get it to trip. It really depends on the duration and magnitude of the surge, as high-frequency inverters can typically handle brief surges but not somewhat longer ones. May be a good followup to see if the auto-transformer helps.
@Bill Johnson What if the inverter only outputs 240v. Would it still be a bad idea to use the auto-transformer? He in the Philippines we have 240v/60hertz from the grid but I have some motors and things from the US that us 120v/60hertz and I would like to use them here. I don't know nearly enough about electricity. I think it's actually 230v/60 but as best I can tell it's close enough. I would like to connect a separate panel that the auto-transformer is connected too.
If this is true, how do LF inverters get away with it? They would have the same issue in passthrough mode. To prevent my autotransformers from becoming overloaded, I derated the breaker sizing for my AT's. 5kva == 20 amp breaker by my math.
Works great for high frequency units also I sell the growatt version of that transformer
Imagine buying an expensive sol-ark inverter and having to buy another accesories to stop it from shutting down, insanity !
I imagine to make this do something significant you'd have to overload one of the legs enough to cause it to fail to provide the desired voltage, in which case the autotransformer would try to help. Or you'd have to use the autotransformer neutral completely and not the solark one so that it would ballance both sides and L1 would always equal L2.
It actually does help balance the two legs even without a heavy load. Not perfectly, but definitely noticeable.
Ben, am I correct in assuming the auto transformer only assists with items that draw 220V of current? Also, the biggest benefit is assisting the surge of power that is required to start the motor of the item, such as a compressor, well pump, etc.? Once in a while, my wife has had complaints about getting her large hair dryer to start, which has been my only complaint about my Sol-Ark 12K.
Actually its the opposite. It's there to help with the 120v loads. It basically works in parallel with the Sol-Ark and balances out any 120v loads to a certain degree, allowing for more available power on each leg.
@@benssolarandbattery Then, by balancing the two, it would eliminate the problem that I am experiencing? I meant to say 120V. Gotta Typo I missed. My wife's hairdryer is 120V, not 220V
@@fisherus very possibly!
roughly how many Ah Capacity (20hr): 186 6 volt batteries will i need to pull the water up 400 feet on 2 hp 220 pump. so far i hav 7 100 watt panels and 4 Ah Capacity (20hr): 186 batteries. i figure im about 40% thare. dose that sound right?
I think I finally got it! Because the Sol-Ark 12K is a transformerless inverter it doesn't balance heavy lopsided loads on one leg. Adding the auto transformer helps stabilize the lopsided leg by adding more power to the opposite leg. What would happen if you paralleled each leg with an auto transformer, one connected to each side?
You need the autotransformer to be attached to both legs and neutral so it will balance out the neutral (120v) current using the opposite leg. I'm not sure that it would work with one on each leg separately.
I was wondering about using the autotransformer on the AC INPUT side. I have a Growatt 5000 and an auto transformer coming. I would like to be able to charge the batteries with my 2 Honda eu2200's in parallel, since I already have those. I figure I could run like 3500 to 4000w with the 2 generators. My question is could that transformer work the other way? Can you put in 120 and get 240 single phase out?
I would love for you to dig into this. Im thinking if you land the AC input onto a breaker in a sub panel, which has 2 additional breakers (one for the auto transformer and a single pole 30 for the generators)
What are your thoughts on this?
Thanks
Ray
Hi Ray,
Yes, the autotransformer works both ways. The limiting factor here is the line in. I believe it would be rated for around half or 2.5kva compared to inputting 240v. I don't believe solaredge posts those specs, but it you look at other similar autotransformers such as the Outback unit, it should be listed and you can extrapolate.
Ben, what are you doing with that enphase hanging down under your panel? Very curious...
Haha, not too many people notice that down there. It's connected to a single west facing panel that I have bolted to the side of my house over one of the mini split air conditioners. It just feeds into the sub panel and is AC coupled with the rest of the system in a grid outage.
Can the autotransformer be used on any solar system?
Do you think i can use this transformer to regulate the incoming grid voltage to around 230v? my grid fluctuates from 207v to 230v and shuts the grid tie inverters. Any suggestions how to solve this problem on the cheap? thanks
No, this won't help with that. In some places your power company may be able to help, in others not. I don't know off hand of a product that would help but I'm sure they exist.
Hi Ben, solaredge seems to imply that the autotransformer is what supplants the grid feed for your solaredge inverter, when the grid goes down. where does your system derive the ac to connect to your solaredge inverter so the solaredge will make AC power? Is it your hybrid inverter output AC power that convinces the solaredge to turn on? thank you
The hybrid inverter tricks the SolarEdge into thinking the grid is present, so it powers up. You need to be able to handle everything it can output when it fires up. The Autotransformer is there to provide a neutral in their system, but not absolutely required in other systems.
interesting comment about needing to sink all the solaredge output. where do you put your solaredge inverter output if it happens to be making maximum power? I have two 7600 inverters in parallel so might need to put 13kw somewhere. thank you
@Mark Rowland you'll need a battery bank that can handle it, (over 300 amps at 48v) or shut down one of the inverters when the grid is down.
@@benssolarandbattery Hi Ben, that makes sense if the solaredge inverters cant throttle, which I assume they cant since they are normally connected to the grids black hole. Is there a logic level input on the solaredge inverter I can tap into to shut down just one inverter ? An input I can use to switch one inverter off, leave the other solaredge on with the hybrid inverter connected, for the case when the grid is down but I want to charge a reasonable battery and run the house load? Maybe I can make a current monitor on the battery that selects the second inverter depending on which way/how much battery current is flowing? I appreciate you thoughts, thank you, Mark
@Mark Rowland you may be able to get them to throttle with a different grid profile that accepts freq/watt commands. (As the frequency goes up, the output goes down) You can also tie one to a contactor that is held closed by the grid. Grid goes down, that inverter shuts down even if it's combined with the same output as the other.
Ben can it work with 110v for welding and compressor.. Im only doing 110 instead of 220 cause we are off grid
Yes you can input 120v plus a neutral and get 240v out of it. I'll have to double check the spec sheet to see how much you can load it that way.
I have another brand auto-transformer and both this and the 120 to 240 wiring schemes are documented for it. I use it to get 240v for a deep well pump. It has too much idle draw to leave it on all the time, plus it hums. So I only turn it on when I need to run the pump.
If this autotransformer works in parallel with another one (installed in inverter), I suggest, that direct parallel connection of this new autotransformer to the inverter's autotransformer will improve balancing performance of new autotransformer. Because wiring resistance (from autotransformer to panel) can affect balancing performance. But, for full balancing performance of new autotransformer, its neutral must be isolated from inverter's neutral. I.e., this new autotransformer must originate its own 240/120 V branch circuit with its own neutral. But, in this case, we cannot ground this neutral, because, it will have connection to the inverter's neutral through grounding conductors. The only way to see full balancing is to use isolation transformer with 240 V primary and 120+120 split-phase secondary. Is this case, we can successfully ground this new neutral.
Would it be possible to just feed the Sol-rk in with 240v and not the nuetral? That way all of the 120v current would be balanced through the transformer. This should be possible as the Sol-Ark will run two wire 240v equipment so the nuetral from the Sol-Ark is not essential.
@@mendohomepower7492 Many inverters will not accept just l1 and l2 and function those need to sense the neutral connection at least to accept the grid power they need to.
@@teekay1785 That's why the auto transformer should connect to a second subpanel that is downstream from the first critical load panel. That way the Sol-Ark or other split phase inverters can operate 240v three wire loads in the in the first load panel and then the L1, L2 and ground can feed to the second load panel that carries the transformer connection with the 120v circuits. The only glitch could possibly be in the ground but it wouldn't be bonded in the second sub panel.
Question: viewing a signature solar video using european 240v with the solar edge transformer indicated that US split phase 240 volt appliances like HVAC units that only use 240v can be run directly from european style 240 v inverters that are not split phase. Do you know or have an opinion on whether or not this is true?
Yes, it will work perfectly*. The only difference between the US 240 and euro 240 is US 240 is 120v L1 and 120v L2 which equals 240v. Euro 240 is 240v L1 and N. Appliances don't care as long as they run on straight 240v.
*If they need a neutral as well to operate (usually for a control circuit) they won't work.
@@benssolarandbattery Thats certainly what I thought but wasn't as confident as I wanted to be. I somehow thought that maybe the split phase sine wave pattern helped "push" a 240 v motor at 2 different points of a revolution etc.
Let's not forget the hertz difference. 50 in Europe and 60 here. Some equipment objects.
@@mendohomepower7492 good point. All of the inverters I've worked with have that setting adjustable between 50 and 60hz, but definitely something to check for! Thanks for watching!
@@benssolarandbattery Some of the Ebay and Amazon units are 50hz only
Sounds like you have a herd of elephants upstairs.
Could you have connected the autotranformer next to and inline with the Sol ark without the sub panel in between?
Well, you want to give the autotransformer some sort of overcurrent protection, so could move to the main panel. It's connected in parallel with everything else, wouldn't want to double tap the breaker in the Sol-Ark really.
Could you and how would you wire this autotransformer to step up 120v to 240v?
Yes, if you hook up 120v to L1 and neutral to N, L1-L2 is 240v.
Add another one ? Or two
So I am confused I thought you were feeding the SolArk by AC coupling the grid tied Solar Edge which should fix the problem of inductive loads on start up the transformer is now fed by the Solar Edge grid tie and then ac coupled to your critical loads panel thus taking the load before it is satisfied by the SolArk which will work when the sun shines. I have done similar with Sun grid ties to beef up the Enphase although I never run it through a transformer I use batteries to produce the Ac for the Sun grid ties then AC couple that to the critical loads panel. When you kill the grid doesn't it take 5 minutes for the Solar edge to meld with the sine wave of the SolArk.
This is basically to beef up the 120v load handling capacity of the Sol-Ark when we're off grid and the sun is down.
@@benssolarandbattery Where does the power come from to run it?
@@offgridwanabe batteries
@@teekay1785 so the solar edge can run from battery
I see a BIG problem with that if the breaker on the Autotransfomer trips you can have 220 applied to a 120 appliance if the two are imbalanced I would not like a breaker there at all due to that problem. This problem will happen if you are off-grid.
Charles, this would only happen with a 240v inverter with no neutral. My inverter has a neutral as well so no issue if the autotransformer breaker trips.
@@benssolarandbattery Then there is no need for the transformer and only serves to burn power.
@@Labeeman when on grid, you're correct. It serves no purpose. When off grid its there to assist the inverter with heavy inductive loads that the inverter by itself was having issues with.
@@benssolarandbattery Then the inverter is not supplying a true split-phase and it is desirable to have the transformer like a low-frequency inverter with a transformer. There are inverters that that transformer is required for 120 service as they are 240 only with no center tap (neutral) think overseas.
can anyone tell me why america can not move on from 120v system, many of these problem goes away by simply switching to 220v system.
America can't do a lot of things... this would apparently be one of them. It would take a very long time and be extremely costly.
Can two of these autotransformers be paralleled for added performance if needed?
Yes, you can parallel them.
So what were the results? Also, how much did the AT add to the draw?
It helped balance the load, enough to make a difference. Also helped with starting the compressor! Pulled about 18W idle.
@@benssolarandbattery Nice. I was expecting more draw (40-50W?) The more I think about this addition, I'm assuming you'd really only want to use this off-grid and honestly any serious problematic loads should probably be 240V anyway.
Would it be possible to just feed the Sol-ark in with 240v L1 and L2 and not the neutral? That way all of the 120v current would be balanced through the transformer. This should be possible as the Sol-Ark will run two wire 240v equipment so the neutral from the Sol-Ark is not essential. If you could try that you should get a completely balanced load on the Sol-Ark.
This could possibly be accomplished through a second sub panel where only the L1 and L2 leads plus ground enter it from the Sol-Ark via the first load panel and the transformer is connected in the second load panel.
Yes, it absolutely would be possible, but then all of the neutral current would be running though the Autotransformer and then I have to be able to shut then entire system down if the Autotransformer trips off due to overload, otherwise I fry things. I prefer to leave it this way, as the Autotransformer will help the Sol-Ark but not entirely take over the 120v loads.
@@benssolarandbattery I think I'll try it that way on one of my systems. The Sol-Ark is really finicky with pumps and things that are 120v. It hits that 4800w per leg ceiling much too often for my liking and reboots the system. The folly of high frequency systems. I may need two auto-transformers to pull it off but I think it would be worth it to have the sol-ark just feed the grid, charge the batteries and take care of 240v loads. The load balancing of the 120v end would be perfect as well.
@@mendohomepower7492 Nice idea. I have the same issues.
@@mendohomepower7492 Please let me know how that works out!!
@@raywarner8874 I am setting up one with a pair of 240v Growatt 5k units this next week. I will be doing the Sol-Ark next month or so.
I am curious if this is any better on the 15k.
I'd have to assume it is, but haven't installed a 15k yet.
Do you know whats the idle draw on that unit?
The autotransformer draws around 18W. The Sol-Ark 12k is around 70-80W.
without adding a lot of power on L1 or L2, it doesn't show much.
Don't work on ...zaaappp... Live wires 😂