timselectric
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What transformer?
L1 and L2 output from 5000?
5000ES + Autotransformer (my specific setup) input
- Thread starter Shale MacGregor
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L1 and L2 output from 5000?
timselectric
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Should have a breaker or fused disconnect between. But, the overload protection of the inverters output is much lower than what the transformer is rated for.
So, it's really a matter of convenience and piece of mind.
Ah yes, having a disconnect makes sense. Just trying to simplify things. I want to do the same layout as shown on the schematic, but I want to also include grid connection along with a bypass should I ever have any failure with the inverter and/or transformer.
timselectric
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Something else to be mindful of.
If the transformer is connected with the grid, it will be in parallel with the grids transformer. If there's a problem with the neutral from the grids transformer, your transformer will be trying to carry all loads connected to the grids transformer. Which could be a few of your neighbors.
If the transformer is connected with the grid, it will be in parallel with the grids transformer. If there's a problem with the neutral from the grids transformer, your transformer will be trying to carry all loads connected to the grids transformer. Which could be a few of your neighbors.
Do you know much about the victron transformer? I was following another thread where a fellow mentioned how this transformer can solve those issues when connecting to grid. You may have seen it back then, but take a look and let me know what your opinion is about it. Unfortunately I'm one of those who jumped on the 5000es bandwagon early on with the thought that using the grid as back-up wouldn't be an issue. Now I'm in limbo trying to safely put this system together.
timselectric
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I'm running a 5000 with no issues.
Per my own modifications.
I posted a thread on my build.
Not good with technology, so not sure how to post a link to it.
Was about a week ago.
timselectric
If I can do it, you can do it.
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Growatt SPF-5000-ES AT and N/G solutions
First, let's point out the issues with this inverter for use in a split-phase system. 1) this inverter was designed for use in a 230v grounded installation. (European standards) It's input and output are L1 and "N". This input "neutral" is expected to be grounded by the grid, and at the...
diysolarforum.com
I'll check it out, thanks.Figured it outGrowatt SPF-5000-ES AT and N/G solutions
First, let's point out the issues with this inverter for use in a split-phase system. 1) this inverter was designed for use in a 230v grounded installation. (European standards) It's input and output are L1 and "N". This input "neutral" is expected to be grounded by the grid, and at the...
timselectric
If I can do it, you can do it.
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Not sure if it will help you with your situation. But, it will give insight into the issues.
Hello, I'm in the process of putting together a system similar to yours, but only with 1 inverter. How did you determine the breaker size for the inverters. I would think since the victron already has a breaker, can you use any size so long it does not get close to 100Amps?
timselectric
If I can do it, you can do it.
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The SPF-5000-ES can take up to 40a input. (Size wire according) the manual recommends #8 wire and a 50a breaker for the output. (Per unit)
Ok, Thanks! Just might get this system finally running.
Shale MacGregor
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My understanding is use the breakers to protect the wires, size according to system
RCinFLA
Solar Wizard
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Victron is one of the few autotransformer setups that is safe. It has its own controller board that keeps tabs on autotransformer temp. The controller trips the CHiNT S9 solenoid trip assist attachment to CHiNT double pole breaker if autotransformer overheats from too great 120vac phase load imbalance.
The setup looks fine. It shuts down all power to panel if autotransformer overheats. Shutting down all power to panel is required so floating neutral in breaker panel is prevented.
SolarEdge has a K type thermocouple mounted against autotransformer core but works with SolarEdge inverters that have thermocouple input to shut inverter down if autotransformer gets too hot.
Growatt's autotransformers have nothing to protect transformer from phase imbalance overload.
Although SolarEdge and Growatt sell them as 5kW autotransformers they are actually only 2.5 kVA continous imbalanced load transformers.
Believe SolarEdge has discontinued their autotransformer since they now produce a spit phase inverter model.
The setup looks fine. It shuts down all power to panel if autotransformer overheats. Shutting down all power to panel is required so floating neutral in breaker panel is prevented.
SolarEdge has a K type thermocouple mounted against autotransformer core but works with SolarEdge inverters that have thermocouple input to shut inverter down if autotransformer gets too hot.
Growatt's autotransformers have nothing to protect transformer from phase imbalance overload.
Although SolarEdge and Growatt sell them as 5kW autotransformers they are actually only 2.5 kVA continous imbalanced load transformers.
Believe SolarEdge has discontinued their autotransformer since they now produce a spit phase inverter model.
Yes you are correct, wire size does need to be taken into account. I'll keep that in mind as well.
burgerking
New Member
Can ES handle assymetrical L1 L2?
Because if it cannot, then you might find yourself in a situation wherein a small deviation from Grid's L1, L2 might cause your ES to overload trying to balance the whole grid...
Because if it cannot, then you might find yourself in a situation wherein a small deviation from Grid's L1, L2 might cause your ES to overload trying to balance the whole grid...
GXMnow
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I found a Victron PDF for the "100 amp" auto transformer.
It is rated to handle a maximum neutral current of 32 amps for up to 30 minutes, and 28 amps continuous. What that means is you could have up to 3,360 watts of imbalance between the two phases. With one 5,000 watt inverter, that probably won't be an issue, but with 3 x 5,000 watt inverters, 15,000 watts total, I could see that becoming a huge problem. The "100 amp" version only makes sense if most of the loads are 240 volt, and there is little chance of running more than 3,000 watts of unbalanced 120 volt loads.
When I am off grid with my Schneider inverter (it has a built in split phase transformer), I had to move a few loads to keep my phases balanced better. It turned out my Toaster, microwave, and refrigerator were all on the same phase initially. If all three are on at the same time, it comes close to 3,000 watts of 120 volt load. I moved the microwave over to the other phase, so it is now closer to 1,500 watts on each leg. While on grid, I also have the clothes washer and dryer on one leg, and had to swap the dishwasher to the other leg. Again, all three come close to 3,000 watts. Phase balance is not quite as important on grid, since while on grid, the utility transformer is forming my neutral, but I still didn't like seeing one leg exporting 2,500 watts while the other leg was importing 2,300 watts. That was a 4,800 watt imbalance. By moving the dishwasher over, as well as the microwave, the legs rarely exceed about 6 amps out of balance. I still see one leg importing 340 watts while the other is exporting 380 watts, but it is far less neutral current now.
While I am "Grid Tied" my system is basically acting like it is off grid now. I have the Schneider Inverter "Export" enough power to the grid side to cover all of the loads in my house main panel, unless it exceeds the 6,800 watt maximum. The same happens when the sun is up and the solar is producing. The solar produces 240 volts and feeds across L1 and L2. And the grid transformer is again the autotransformer. Until I added the Schneider hybrid inverter, I had no idea how out of balance my loads were. As it turns out, there were times I had as much as 6,000 watts of imbalance. So when my solar was producing, it was basically only exporting on one leg, and importing even more power on the other leg. The grid can take it, but off grid this is a serious problem.
Whenever you are working with split phase (or 3 phase) power, you should measure all your loads and try to evenly spread them across the phases. The closer you can balance the loads, the less neutral current you will have. When running from any inverter, this can be a big deal. Most high frequency inverters are basically half the power on each leg. The Sol-Ark units are a good example of this. The 12K can only put out about 5,000 watts on either leg. The low frequency Schneider XW-Pro with the giant transformer does a little better with imbalance, but since it is only a 6,800 watt inverter, the 120 volt single leg power still falls around 5,000 watts. And using the Victron auto transformer, a single leg (or the total imbalance) can only be about 3,360 watts.
It is rated to handle a maximum neutral current of 32 amps for up to 30 minutes, and 28 amps continuous. What that means is you could have up to 3,360 watts of imbalance between the two phases. With one 5,000 watt inverter, that probably won't be an issue, but with 3 x 5,000 watt inverters, 15,000 watts total, I could see that becoming a huge problem. The "100 amp" version only makes sense if most of the loads are 240 volt, and there is little chance of running more than 3,000 watts of unbalanced 120 volt loads.
When I am off grid with my Schneider inverter (it has a built in split phase transformer), I had to move a few loads to keep my phases balanced better. It turned out my Toaster, microwave, and refrigerator were all on the same phase initially. If all three are on at the same time, it comes close to 3,000 watts of 120 volt load. I moved the microwave over to the other phase, so it is now closer to 1,500 watts on each leg. While on grid, I also have the clothes washer and dryer on one leg, and had to swap the dishwasher to the other leg. Again, all three come close to 3,000 watts. Phase balance is not quite as important on grid, since while on grid, the utility transformer is forming my neutral, but I still didn't like seeing one leg exporting 2,500 watts while the other leg was importing 2,300 watts. That was a 4,800 watt imbalance. By moving the dishwasher over, as well as the microwave, the legs rarely exceed about 6 amps out of balance. I still see one leg importing 340 watts while the other is exporting 380 watts, but it is far less neutral current now.
While I am "Grid Tied" my system is basically acting like it is off grid now. I have the Schneider Inverter "Export" enough power to the grid side to cover all of the loads in my house main panel, unless it exceeds the 6,800 watt maximum. The same happens when the sun is up and the solar is producing. The solar produces 240 volts and feeds across L1 and L2. And the grid transformer is again the autotransformer. Until I added the Schneider hybrid inverter, I had no idea how out of balance my loads were. As it turns out, there were times I had as much as 6,000 watts of imbalance. So when my solar was producing, it was basically only exporting on one leg, and importing even more power on the other leg. The grid can take it, but off grid this is a serious problem.
Whenever you are working with split phase (or 3 phase) power, you should measure all your loads and try to evenly spread them across the phases. The closer you can balance the loads, the less neutral current you will have. When running from any inverter, this can be a big deal. Most high frequency inverters are basically half the power on each leg. The Sol-Ark units are a good example of this. The 12K can only put out about 5,000 watts on either leg. The low frequency Schneider XW-Pro with the giant transformer does a little better with imbalance, but since it is only a 6,800 watt inverter, the 120 volt single leg power still falls around 5,000 watts. And using the Victron auto transformer, a single leg (or the total imbalance) can only be about 3,360 watts.
If the imbalance does become an issue for 3 inverters, can adding a second autotransformer remedy that issue?
GXMnow
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That would be a good question for Victron.
In theory, two auto transformers in parallel should be able to handle twice as much neutral current, but the windings in the two transformers would need to match exactly. If one side is off by a single turn, it could cause a hug amount of current to flow due to the small voltage difference between the two neutrals. So it comes do to how accurate their center tap is. If they are exact center taps, they should share the current equally. I would connect the L! and L2 leads first, leave the neutrals open, and measure the voltage between the two neutral leads to make sure you get basically zero volts. Even a few millivolts at no load is not good. If the voltage is really low, then connect the neutrals together through an ammeter and that should also read zero. Any current you get doing that will be wasted power being drawn from the inverter(s) driving the transformers.
