Optimizers... what are they good for?

[Willy3]

I’m a bit suspicious of Tesla low balling production estimates/guarantees. This combined with the reports of difficulty with customer service makes panel level monitoring attractive to me, which in turn makes optimizers attractive. I don’t even have shade on my roof.

Edited: okay, I just saw your post above mine right after I got done writing this one. Point taken

 

[nwdiver]

I’m a bit suspicious of Tesla low balling production estimates/guarantees. This combined with the reports of difficulty with customer service makes panel level monitoring attractive to me, which in turn makes optimizers attractive. I don’t even have shade on my roof.

Edited: okay, I just saw your post above mine right after I got done writing this one. Point taken

I do agree that Tesla is offering a killer deal right now. If your options are Tesla solar with Solar Edge and optimizers for $2.01/w or a local installer for $2.50/w with a regular string inverter then it's hard to argue against Tesla. I think there's a good chance Tesla is installing these systems at or possibly below cost to regain market share.

I just wouldn't add optimizers or module level monitoring to my list of 'must-haves'. They're barely on my list of 'nice-to-haves'.

 

[CrazyRabbit]

panels manufactured today have diodes where they didn't always.

 

[nwdiver]

panels manufactured today have diodes where they didn't always.

Maybe in the early. early. early days like ~1980ish. But you kinda need bypass diodes. It doesn't just increase production if there's shade. It also decreases fires if there's shade.

I built my first array from laminates and didn't know what a 'bypass diode' was. I discovered how necessary they are the hard way. With one cell shaded and no bypass diodes that cell quickly heated up to >200F.

 

[niveknow]

That's kinda my point with this thread. You may not see it on your invoice but it costs ~$60 per panel for optimization + monitoring or ~$30 just for monitoring. That adds up quick. So for a 10kW system that's ~$1800 for optimization or ~$900 just for monitoring. And for all that added expense there's really no added value.....

Panel failure is exceedingly rare. In >10 years I've never seen a broken panel that was working when installed aside from an obvious mechanical failure like broken glass from stress or an impact but even in that case the panel was still working. Panel failures can be spotted from a decrease in production then the exact panel can be narrowed to the string. IMHO $900 on module level monitoring isn't worth the <1% chance there will be a panel failure in the life of the system OR the ~20 minutes of additional troubleshooting required to find a bad panel absent module level monitoring.

Adding optimization also makes a failure FAR more likely. While I've never seen a panel fail I have seen several optimizers fail.

Hello - How did you arrive at the ~$30 for monitoring? The optimizer are coming standard with Tesla these days which may be what you suggested by the single all-in price. I'm still not clear on how to get visibility to a panel or optimizer failure besides seeing a production drop. Imagine again a brand new system where a single unit was not working correctly from the start. These would be no baseline to see production drop. Is there a way maybe through the SE inverter to see failures?

 

[nwdiver]

Hello - How did you arrive at the ~$30 for monitoring? The optimizer are coming standard with Tesla these days which may be what you suggested by the single all-in price. I'm still not clear on how to get visibility to a panel or optimizer failure besides seeing a production drop. Imagine again a brand new system where a single unit was not working correctly from the start. These would be no baseline to see production drop. Is there a way maybe through the SE inverter to see failures?

I arrived at $30 for monitoring because that's the cost of the equipment per panel;

In my OP you can clearly see the production of each panel if you have module level monitoring. Even without module level monitoring it's not hard to narrow down the failure to a string and from there find the panel.

 

[niveknow]

I arrived at $30 for monitoring because that's the cost of the equipment per panel;

In my OP you can clearly see the production of each panel if you have module level monitoring. Even without module level monitoring it's not hard to narrow down the failure to a string and from there find the panel.

How does one enable module level monitoring if the $30 optimizer per panel are already installed? Is it a setting or view in the Tesla app?

 

[nwdiver]

How does one enable module level monitoring if the $30 optimizer per panel are already installed? Is it a setting or view in the Tesla app?

The optimizers are ~$60 not $30.

To see module level production you may need to contact Tesla. That data isn't available on the Tesla app as far as I'm aware. It needs to be accessed through the solar edge app and you need certain permissions. Some 'roles' only allow visibility of the system.

 

[niveknow]

The optimizers are ~$60 not $30.

To see module level production you may need to contact Tesla. That data isn't available on the Tesla app as far as I'm aware. It needs to be accessed through the solar edge app and you need certain permissions. Some 'roles' only allow visibility of the system.

View attachment 569499

Perfect. I guess I need to let Tesla know that I'm concern about some inefficiencies in couple of the panels and would like for them to enable access for SolarEdge app so I can investigate. Thank you.

 

[gavine]

I don't get why they don't just go for microinverters to be honest.

I recall seeing an interview with Lyndon Rive, the former CEO of SolarCity where they asked him about microinverters. His response was that inverters have a certain failure rate and in terms of warranty/support costs, to him it made sense to have one or two inverters per install instead of 20+. With micros, there's a higher probability that they would need to service more systems.

 

[BrettS]

I recall seeing an interview with Lyndon Rive, the former CEO of SolarCity where they asked him about microinverters. His response was that inverters have a certain failure rate and in terms of warranty/support costs, to him it made sense to have one or two inverters per install instead of 20+. With micros, there's a higher probability that they would need to service more systems.

It’s an interesting thought, but they are putting optimizers on each panel as it is. Maybe optimizer failure rates are lower than microinverter failure rates, but it doesn’t really seem like there would be that much of a difference.

 

[gavine]

It’s an interesting thought, but they are putting optimizers on each panel as it is. Maybe optimizer failure rates are lower than microinverter failure rates, but it doesn’t really seem like there would be that much of a difference.

Maybe the interview was before they started using optimizers? Not sure. I have just been assuming that optimizers are more-reliable than microinverters. But again, I really don't know.

 

[BrettS]

Maybe the interview was before they started using optimizers? Not sure. I have just been assuming that optimizers are more-reliable than microinverters. But again, I really don't know.

Yeah, that’s possible. I believe they were using delta string inverters with no optimizers for a while.

Honestly, from all the research I’ve done it seems like optimizers and microinverters really have very similar benefits and efficiency levels. I’m not sure that there are very strong reasons to choose one over the other. (And if you ask @nwdiver there’s little reason to get either of them)

I’ve also found that a lot of installers that use microinverters are hard selling them and even using disinformation and scare tactics to make people believe that microinverters are some sort of miracle gift from god and you would be crazy to even think about using anything else. If you look at the data you will find that their claims really aren’t true, but it does explain why we get a lot of messages on here asking why on earth Tesla doesn’t use microinverters.

 

[nwdiver]

It’s an interesting thought, but they are putting optimizers on each panel as it is. Maybe optimizer failure rates are lower than microinverter failure rates, but it doesn’t really seem like there would be that much of a difference.

There's A LOT less going on in an optimizer vs a micro inverter. An optimizer has tracks the MPP curve and adjusts output voltage up or down. It's basically just a smart boost-buck converter. A micro-inverter does that AND tracks grid frequency AND converts DC-AC.

 

[BrettS]

There's A LOT less going on in an optimizer vs a micro inverter. An optimizer has tracks the MPP curve and adjusts output voltage up or down. It's basically just a smart boost-buck converter. A micro-inverter does that AND tracks grid frequency AND converts DC-AC.

Yeah, I realize that they function in completely different ways, but what I’m saying is that if you look at the ‘advantages’ that installers keep talking about then you get those same ‘advantages’ from optimizers as well. “Well, our microinverters won’t let your whole system suffer from one shaded panel”, or “Well, with our microinverters you’ll get panel level production data”.

 

[nwdiver]

Yeah, I realize that they function in completely different ways, but what I’m saying is that if you look at the ‘advantages’ that installers keep talking about then you get those same ‘advantages’ from optimizers as well. “Well, our microinverters won’t let your whole system suffer from one shaded panel”, or “Well, with our microinverters you’ll get panel level production data”.

My understanding is that the reduced complexity lowers the failure rate. I agree the selling points are essentially the same.

It's a little amusing that this topic has become somewhat 'tribal'; I've conversed with people that think ALL systems should be 'optimized'. Why? For example; I installed a 22.77kW ground mount recently consisting of 66 panels. No rapid shutdown required because it's a ground mount so using optimizers would have increased the material cost (66)($60) = $3940. What am I getting for ~$4k aside from 66 additional failure points?

I have a 'toy' 4kW system I play with just to get the feel for how panels 'behave'. Due to a charge controller failure I had to lower the DC Voltage recently so I was running a string of 7 panels in parallel with 8, so differing voltages in parallel (far from optimum). Surprisingly the output loss wasn't much more than 1/16th. MPP is a curve. There's often not much difference between multiple points on that curve. Adding electronics to a panel to enable that panel to more precisely find it's individual MPP is simply not beneficial.

 

[pdx_m3s]

One thing to think about is that Tesla is on the hook for system repairs/maintenance for 10+ years. Having optimizers may reduce the troubleshooting time and effort such that the optimizers pay for themselves over the long term.

For me, do I need optimizers? No. But I'm getting them at no additional cost and I'll be able to view individual panel performance.

 

[mckemie]

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.

 

[mckemie]

Incidentally, I've had good success using inverters (both string and micro) that do "double duty" with both east and west facing panels.

 

[nwdiver]

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.

There's no good solution. SE inverters need optimizers, the inverter doesn't have MPPT, that's a function delegated to the optimizer. You could probably pickup a cheap SMA or Fronius string inverter for less if you keep an eye out.