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Optimizers... what are they good for?

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This is a topic of high interest to me right now. Some 5kw surplus SE inverters have come on the market recently for <$400. I BADLY need to learn how to use them without the expensive optimizers. Any suggestions? I have a test inverter which I have not been able to get to work. The next test will be to put one or two optimizers in the string.

So it’s my understanding that modern solaredge inverters require optimizers. However, they do allow two panels per optimizer if you get one of the larger optimizers, so that might save some cost. There was also someone who posted recently about tesla calling for a SolarEdge string optimizer, model number SO5000. The data sheet for this device was posted here:

The latest systems components y'all getting from Tesla these days?

I have never seen or heard of this device before and I spent a bit of time googling it and I couldn’t even find any references to it anywhere. But it appears that it is a single optimizer that will handle a whole string of panels. If you can figure out where to get such a thing then it might be an option for you as well.
 
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Thanks but I don't "a" inverter. I need 10+. I've tried quite a few and found the old transformer inverters are trouble free compared to the newer transformerless. There has been a good supply of 4kw SMAs on the market but I did not buy enough and they seem to be no longer available. If you can point me to a good reliable old 4-6kw in good quantity, I would be grateful.
 

Hmmm... that would be interesting. String level
optimization has some benefits but I wonder how they would comply with rapid shutdown. I guess that could be used on carports or ground mounts where rapid shutdown isn't required.

Honestly, I’d love to know more about it, but I wasn’t able to find anything at all in my google search or even looking on SolarEdge’s site. The only official (or even unofficial) documentation I’ve seen is the data sheet that was posted in the other thread and that has very little info.
 
Thanks but I don't "a" inverter. I need 10+. I've tried quite a few and found the old transformer inverters are trouble free compared to the newer transformerless. There has been a good supply of 4kw SMAs on the market but I did not buy enough and they seem to be no longer available. If you can point me to a good reliable old 4-6kw in good quantity, I would be grateful.

You might be out of luck there. I had seen ~4kW inverters going for $400 to clear the inventory, it looks like it's all been cleared now. But if you're looking to install ~40kW of solar you definitely don't want to stick a $60 optimizer on every panel if your objective is to save $$$.

Transformerless inverters aren't that bad. The newer ones have fewer problems than the earlier ones. As with any technology transition there were some teething problems. The cost difference is profound. My first 8kW inverter cost >$3k in 2010 and weighed ~100#, 1 MPPT channel and no wifi connectivity for monitoring. I bought a new 7.6kW inverter a month ago for ~$1200 with 3 MPPT channels and built-in wifi.
 
You might be out of luck there. I had seen ~4kW inverters going for $400 to clear the inventory, it looks like it's all been cleared now. But if you're looking to install ~40kW of solar you definitely don't want to stick a $60 optimizer on every panel if your objective is to save $$$.

Transformerless inverters aren't that bad. The newer ones have fewer problems than the earlier ones. As with any technology transition there were some teething problems. The cost difference is profound. My first 8kW inverter cost >$3k in 2010 and weighed ~100#, 1 MPPT channel and no wifi connectivity for monitoring. I bought a new 7.6kW inverter a month ago for ~$1200 with 3 MPPT channels and built-in wifi.

Do you have suggestions on less troublesome transformerless? Something with variable isolation threshold or defeatable?
Using ground mount and cheap used panels, there is a lot of safety stuff that I just don't care about.

I can live with a single tracker.

My newest project is installing a 50kva transformer for the sole purpose of selling energy to my utility.
 
Do you have suggestions on less troublesome transformerless? Something with variable isolation threshold or defeatable?
Using ground mount and cheap used panels, there is a lot of safety stuff that I just don't care about.

I can live with a single tracker.

My newest project is installing a 50kva transformer for the sole purpose of selling energy to my utility.

SMA inverters should work. I know you can disable most of the protections with a 'guid guard' code. They also make a large 3 phase inverter that would be perfect if you're making a mini solar farm.
 
SMA inverters should work. I know you can disable most of the protections with a 'guid guard' code. They also make a large 3 phase inverter that would be perfect if you're making a mini solar farm.

I have a transformerless 7kw 3 tracker SMA that worked pretty well for a while. It quit working and I never devoted myself to dealing with it's software access; I just hooked it up and observed production. I'd like to know more about SMA grid guard. I'll try googliing up.

I had high hopes for using the surplus SolarCity/Delta H6s that have been on the market for ~$600. They would be ideal for my application if they did not have the isolation fault problem. I may still pursue them. I bought an insulation tester which I hope to learn to use to identify panels that the Deltas do no like. My old 4kw SMA transformer inverters are happy with ANY panels.

I've already elected to install a spilt phase transformer since I don't have any three phase experience and no 3 phase equipment. This project is likely to take nearly a year to complete. If I can identify cost effective 3 phase equipment, my next project could be 3 phase. Using split phase, I've got my installed cost well below $.50/watt excluding labor. Perhaps as low as $.30.

Can you identify some online resource where the elusive SE "string optimizer" might be tracked down?
 
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I think Tesla is using optimizers not necessarily to guarantee or otherwise maximize production, but in flexibility of installations. They just need to throw up the panels and string the panels together. No need to worry about all the panels in a string facing the same way, or occasional shading. Looking at the layouts thread has really shown me how Tesla has a more "throw the panels anywhere" approach to this, and optimizers make it possible.

You've just underscored one of the many benefits of optimizers and that is it provides more flexibility in panel positioning for installs that don't thousands of square feet of south facing roof space.
 
Why? Micros are even worse than optimizers from a cost vs performance perspective. They're also less flexible than optimizers..

And I prefer MIs even of optimizers especially for a DIY install. There is no single point of failure with MIs. One MI goes out and your system is still mostly up and you replace it with the spare you have lying around. If the inverter goes out, you're whole system is down which is catastrophic if you're off grid.
 
My Tesla Solar setup is using optimizers per the technical design plans. 33 panels (2 strings - 16/17). All west-facing. Zero shading. SolarEdge 10kW. Perhaps optimizers are used because of the uneven string length?

Not all installations will benefit from optimizers. Still cool to have the per panel generation data but if you have no shading and everything is in the same direction, you don't really need them...except to point out a panel failure or partial failure which can happen.
 
And I prefer MIs even of optimizers especially for a DIY install. There is no single point of failure with MIs. One MI goes out and your system is still mostly up and you replace it with the spare you have lying around. If the inverter goes out, you're whole system is down which is catastrophic if you're off grid.

I mean if you’re in a situation where something catastrophic happens if your inverter goes down and you would have a spare MI then there’s no reason that you can’t have a spare inverter on the shelf either. Of course that spare inverter is going to cost $2500 instead of $150 for an MI, but that’s not so high that it’s cost prohibitive to avoid a ‘catastrophic’ outage.
 
I mean if you’re in a situation where something catastrophic happens if your inverter goes down and you would have a spare MI then there’s no reason that you can’t have a spare inverter on the shelf either. Of course that spare inverter is going to cost $2500 instead of $150 for an MI, but that’s not so high that it’s cost prohibitive to avoid a ‘catastrophic’ outage.

The MIs are WAY cheaper than a full on inverter. I wouldn't have a spare inverter just lying around.
The other thing about MIs is that it's so much simpler to expand your system. You don't even have to use the same panels or MIs, They're completely self contained generation units.
 
The MIs are WAY cheaper than a full on inverter. I wouldn't have a spare inverter just lying around.

Yeah, I agree, and I don’t think most people would. But again, in your example where you someone is completely grid and if in inverter goes down they have no power, then it probably makes sense to keep a spare inverter on hand. My point was simply that it is possible to avoid the catastrophic situation where you have no power for 3 weeks while you’re waiting for a warranty inverter.
 
Yeah, I agree, and I don’t think most people would. But again, in your example where you someone is completely grid and if in inverter goes down they have no power, then it probably makes sense to keep a spare inverter on hand. My point was simply that it is possible to avoid the catastrophic situation where you have no power for 3 weeks while you’re waiting for a warranty inverter.


..or even a whole day. Even if you have a spare inverter lying around and even if it takes the same amount of time to swap and inverter vs swapping a micro inverter(like if it's under a panel that is hard to access), if you lose the MI, your sytem stays up generating power minus one panel. If you're main inverter goes down and it takes you the better part of a day to swap it out, you end up up not charging your batteries that day and may run out of power entirely.
 
And I prefer MIs even of optimizers especially for a DIY install. There is no single point of failure with MIs. One MI goes out and your system is still mostly up and you replace it with the spare you have lying around. If the inverter goes out, you're whole system is down which is catastrophic if you're off grid.
If you're off grid, you're more likely to have solar charge controllers connected directly to the battery pack. AC Coupled systems are much less common in true off-grid situations.