Questions on Tesla Solar Inverter vs. Enphase Microinverters

[jjrandorin]

I have A 2015 solar city (now Tesla) install. If I were buying now, the choice for me would be between Tesla and Third party, with Tesla being a purely cost consideration. If I was going to go with a third party install, I would also likely go with microinverters.

The biggest reasons reasons would be the ones that @BGbreeder already laid out, which were:

1. If one of your microinverters goes out, you might lose 2% of your production until it is fixed. If one of your inverters dies, you are out closer to 50%.
2. Microinverters warranties are 25 years or so. Inverter warranties are 7-10 years. The manufacturers know the longevity of their products, and we don't. To me the warranty length difference is a reflection of the manufacturer's expectations for how long they expect the item to last.

There generally is a cost difference going with a third party vs Tesla directly, but if I was already going with a different supplier than Tesla, I would probably want microinverters. Maybe not the priciest iQ8s or something, but whichever ones would work with powerwalls (IQ7? IQ7+? I dont know these model numbers and features).

I dont have any specific issue with Tesla solar, my system has worked well, and they have addressed issues I ended up having with my powerwalls to my complete 100% satisfaction, however it did take quite a bit of time and quite a bit of "gentle, polite prodding" for that to happen. If I was already going with a third party, I would look hard at microinverters, and also upgraded panels, but thats just my own personal opinion. No wrong answer here at all.

 

[h2ofun]

I have A 2015 solar city (now Tesla) install. If I were buying now, the choice for me would be between Tesla and Third party, with Tesla being a purely cost consideration. If I was going to go with a third party install, I would also likely go with microinverters.

The biggest reasons reasons would be the ones that @BGbreeder already laid out, which were:



There generally is a cost difference going with a third party vs Tesla directly, but if I was already going with a different supplier than Tesla, I would probably want microinverters. Maybe not the priciest iQ8s or something, but whichever ones would work with powerwalls (IQ7? IQ7+? I dont know these model numbers and features).

I dont have any specific issue with Tesla solar, my system has worked well, and they have addressed issues I ended up having with my powerwalls to my complete 100% satisfaction, however it did take quite a bit of time and quite a bit of "gentle, polite prodding" for that to happen. If I was already going with a third party, I would look hard at microinverters, and also upgraded panels, but thats just my own personal opinion. No wrong answer here at all.

I paid for 25 year warranty on my inverters

 

[JMGNC]

I have my technical site survey Monday. I’ll ask about microinverters. Thanks for the advice.

 

[TomServo]

I'm just starting on the SOLAR journey, being retired we have to do this in two phases. This fall we are having 31 Q Cell 405-watt panels and 31 Enphase IQ8A Inverters installed on a GRID-TIED system. Our first On-Visit is tomorrow and then they will finalize my design but all along I have told them we will be adding battery backup next year. So the technical solution for the PV system needs to support that. I don't want to pay for equipment that will be replaced next year. I told them my first choice of batteries will be the Tesla Powerwall 3 (will wait) followed by Enphase 5Ps (probably 4).

So with the new Enphase nomenclatures being thrown around IQ Combiner 5C and IQ System Controller 3 that they could use. Are these components compatible with a Tesla Powerwall? Or will I need additional gear? Also with the Tesla app can I monitor individual panel performance/status or will I need to use BOTH the Enphase and Tesla app?

More to follow after my Site Visit tomorrow.

And One More thing: Our average power consumption for the last three years since I retired has averaged 11,600 kWh/yr (electric averages $121/mo) which includes our Model Y. I oversized my system to account for:

1. Reduce power bill to ZERO (my utility offers onto-to-one Net Metering)
2. Charging the battery and powering the house
3. Future system degradation

In preparation, I added these components:

1. Having a Soft-Start device installed on our 3-ton 14 SEER AC
2. Installed a water-powered sump pump backup to my electric sump pump (I can switch that off during outages reducing the load)

Our 1800 sq ft home is 5 years old and highly efficient (added more insulation during construction) with gas heat/range and fireplace)
2. Faces EAST/WEST

I figure 2 Powerwalls (27 kWh) is overkill and 4 Enphase 5P's at 20 kWh is just about perfect.

Appreciate your thoughts/comments

 

[cali8484]

I'm just starting on the SOLAR journey, being retired we have to do this in two phases. This fall we are having 31 Q Cell 405-watt panels and 31 Enphase IQ8A Inverters installed on a GRID-TIED system. Our first On-Visit is tomorrow and then they will finalize my design but all along I have told them we will be adding battery backup next year. So the technical solution for the PV system needs to support that. I don't want to pay for equipment that will be replaced next year. I told them my first choice of batteries will be the Tesla Powerwall 3 (will wait) followed by Enphase 5Ps (probably 4).

So with the new Enphase nomenclatures being thrown around IQ Combiner 5C and IQ System Controller 3 that they could use. Are these components compatible with a Tesla Powerwall?

Short answer is NO. Tesla and Enphase each have their own proprietary battery support equipment (e.g. Tesla Gateway, Enphase iQ System Controller, etc.) that's only compatible with their battery. If you go with Powerwall then you don't need the Enphase iQ8A's since you won't be able to use the extra features in them. You can get the iQ7A's and avoid paying premium for features you won't be able to use.

I figure 2 Powerwalls (27 kWh) is overkill and 4 Enphase 5P's at 20 kWh is just about perfect.

You will likely need 2 Powerwall's for the power (rather than capacity) to run your A/C and remember the typical US household daily consumption is ~30kWH so 27kWH is not really overkill especially with A/C.

 

[jrweiss98020]

I strongly recommend you install the battery backup from the start, even if it is less than you will eventually get. That is the ONLY way you can ensure everything will work together. Also, without the battery backup (& Tesla Gateway) installed, you cannot use your solar when the grid goes down.

With the 10.8 kW continuous / 11.3 kW peak output of those inverters, you will likely be told you need a minimum of 2 Powerwalls (general rule of 1 PW for each 7 kW solar output). With ~3 kW draw from the AC unit, 2 PW will run them for less than 9 hours.

I started with 27 panels with IQ7s, and 2 Powerwalls. I later expanded to 35 panels, and am looking at a 3rd Powerwall. Talk to your installer about any limitations on future expansion.

 

[smjacobs]

Hello, I live in Phoenix, AZ and plan on getting solar installed soon. My energy provider is APS. I have been working with a few Tesla Certified companies that I found through energysage.com and through the Tesla website. I prefer to work with local contractors for service reasons. Right now, I’m looking to install about a 110% production system that comes out to 13KW.

Anyways, I’ve been happy with my last couple of bids but am completely torn on which type of inverter to choose. I have read many positives and negatives about both types – Tesla String Inverter vs. Enphase Microinverters. The plan is to add a Tesla Powerwall or two in the coming years. One company seems totally fine with installing the Tesla inverter as it would be a 1:1 replacement if there are any issues, but have also made it very clear they don't sell many of them. Both companies have shared thier most common sale are Enphase Microinverters plus Tesla Powerwall.

I wasn’t aware that I could even use Enphase microinverters until I did some research. Does anyone else have some other opinions on this choice? I have zero shade on my roof but also don’t like the fact that if the Tesla inverter goes down, so do I. But, what is the actual failure rate? Should I not be confident in their product? Are there any other things I should be investigating prior to my decision? As a Tesla FanBoy, I want to get the String Inverter but the downside seems quite risky...

All opinions and thoughts are welcome. Thank you in advance!

Go w the Enphase microinverters. This is coming from someone who's had a failed Tesla inverter that knocked down my system for over 5 months while it took forever for Tesla to finally fix their failed inverter. If I knew what I know now I would have done Enphase microinverters for SURE.

 

[WilliamG]

I have 10 kW of LG panels, Enphase microinverters, and 2 Powerwalls, installed by a local (Seattle) company. Initial install is a bit more expensive, but I think it's worth the peace of mind NOT having a single point of failure for the whole system. Also, when I wanted to expand, it was seamless.

If you can afford it, get the Powerwalls with the initial install. Without them and the Gateway, you cannot use the solar panels during a grid outage. You will also be assured the entire system works as advertised from the beginning, obviating some of the horror stories seen elsewhere in this forum.

Sent you a PM!

 

[WilliamG]

Anyone in Seattle use Northwest Electric and Solar?

 

[jrweiss98020]

Nope. A&R Solar here.

 

[furuike]

The cost of solar panels have fallen so much that microinverters now represent a significant part of the solar install. If you have little shading (true for me), then an inverter with 4 MPPT string trackers is often a way easier install and fewer materials.

Microinverters are also another item that can break. Yes if they break you only lose a small portion of your output, but it's very inconvenient that they break in the first place!

I agree the monitoring is nice, but I would not be willing to pay much extra per watt for microinverters or optimizers. I'd rather spend that money instead on more panels.