Tesla Powerwall or Enphase 5P

[CA_Paul_PV]

Hi. I'm in SoCal, and looking to expand our existing 3kW system by adding 11kW of Panels and 10kWh of Battery storage.
I'm considering either:
27 400w Panels w/ IQ8 uInverters and 2 Enphase 5P Batteries or
27 400w Panels w/ 1 Powerwall3 Battery and integrated Inverter
I will need to move to NM3.0 w/ TOU rates, and there's not much credit for overproduction. Eventually, I will double the storage size, but will do that in a second phase, hopefully as battery prices decrease.
We are not too concerned about grid outages in our area, but Grid down backup is a plus.

The pricing is fairly similar between the two options, but there are some major differences in technology and installation.
1. Enphase uInverters have the benefit of optimizing by panel, but my roof has full sun w/o any shade, so I'm not sure this is a big issue. Thoughts?
2. The enphase solution requires a transfer switch, Controller, and a SubPanel for the backed up loads. Whereas the Tesla Solution uses a backup interface switch between the main panel and the POCO meter and the entire panel is backed up. The Tesla solution seems cleaner from a wiring and install point of view. Also, I have a 200A Bus Bar in my Panel so w/ Enphase I may need to derate my Main Breaker to 175A to add 25 more panels and that would be close to my total Load of 170A.
3. Does either have a benefit regarding future expansion of Panels or Batteries? The Enphase 5P Batteries seemed quite straightforward to add later, and I could probably do that on my own for $3500 each, whereas the Tesla requires a certified installer and would be 10-13k each additional.

Existing system is (16) 200W Panels w Sunny Boy string Inverter.

It seems like there are some real experts on this Forum, with lots of experience, so I'm looking for your feedback and advice on the better long term solution. Thx

[Rade]

Start by asking yourself "How much of this do I really want to manage in the long run?"

When we were looking at solar options, we looked at who was manufacturing and servicing the components. We watched every YouTube video we could find. Talked with neighbors about they solar experiences, sent out for numerous proposals. We looked at at the "Door knocker" and regional "Mom & Pop" solar installers who cobble together parts from different vendors, and we looked at Tesla and Generac. Neighbors who went with the "Door Knocker" (Can we lease your roof?") and "Mom & Pop" installers (they were considerably cheaper) got what they paid for - the installations look awful on the houses and service has been dubious at best. Here in New England, Tesla does no have much of a footprint, and the regional installation / servicing has been deemed unacceptable by the early adopters. As I posted elsewhere - that is here; in your region Tesla may be far better. We opted to go with a Generac solar solution; the installation looks incredible and the service has been quite acceptable (one phone number to call / text if we have an issue) and we have a 20+ year warranty on all of the Generac installed components. Net: I don't have to go up on the roof to trace wiring or look at the inverters LINUX code if something goes sideways.

I would go the route of talking with folks in your region, your neighbors, etc. who have used either of the vendors and find out what their experiences have been, and look at sites like your local BBB website on the companies who would ultimately be supporting any warranty work. I hear Tesla is quite good in areas where it's well established. The solar shingles had us intrigued, but it came down to the overall regional servicing and support in the long run.

If you are kicking the tires on Tesla, one Vlogger I like is Marques Brownlee. He went all in on the Tesla Powerwall and has a pretty good YouTube video on his experience (https://youtu.be/UJeSWbR6W04?si=ASDCJNSBUgW_qUG1) Might be worth a look-see.

Rade

[solardreamer]

Many pros and cons between Tesla and Enphase. Both are closed proprietary systems (can use only their batteries) that allow little third-party integration/compatibility. So, you are much stuck to their ecosystem.

Tesla pros/cons:
+ Full integration with Tesla EV's (e.g. charge on solar) and integrated app/monitoring.
+ Cheaper usually.
+ Better support for existing third-party solar (i.e. Sunny Boy).
- Terrible customer support.
- Less equipment reliability.
- No generator integration.
- Limited customer control of battery charging from grid.

Enphase pros/cons:
+ Modular, more flexible expansion.
+ Better for shading.
+ Good customer support.
- Worse support for existing third-party solar.
- Expensive and limited generator integration.
- Limited real-time/local monitoring and reliable comms.
- Fast obsolescence of product models with little backwards compatibility (i.e. no easy expansion for earlier generation products).


Frankly, if you don't have shading issues then a better (expandable/backward compatible) long term solution could be a less proprietary hybrid string inverter (e.g. Schneider, etc.) system that allows open integration and compatibility with third-party batteries and existing solar inverters.

[CA_Paul_PV]

Thanks Rade. Good feedback
Thanks Solardreemer. I think that's a fair comparison. I haven't considered Schneider, but I'll look into them. What 3rd party batteries would be worth considering? To Rade's point, I don't mind doing some upfront install work, but I don't really want to be a slave to servicing/managing on a daily basis. But I'm open to less expensive options if it makes sense.

One of the real challenges with the new TOU and NM3.0 agreement is to have it make financial sense without adding a ton of really expensive batteries.
Essentially, you need to store at least enough energy to make it through the Peak 4-9pm $.68/kWh rates. Which in our case is 11kWh.
Then if your commuting w/ an EV and need to charge it at night as well then you would need another 15-20kWh of storage or your paying $.25kWh to charge your car even though you have an expensive solar and battery system.
For 25kWh of Battery storage alone your talking 20-30k with either solution.

[Rade]

One of the real challenges with the new TOU and NM3.0 agreement is to have it make financial sense without adding a ton of really expensive batteries.

We opted for the Generac 18kW battery system (not the propane generator). We've lived in our home for nearly 20 years, and experience one or two power hits a year lasting nor more than a few hours (though one went for 2 days during a blizzard). We had a sub-panel installed off the inverter that has 6 "critical" circuits on it; refrigerators, freezer, mini-split, a couple of kitchen outlets. Since the solar installation, we had one outage of about 10 minutes. The outage used all of 2% of the battery storage (furnace was running). The upside there was that, where several of our neighbors have propane or gasoline generators, we had PEACE AND QUIET during the outage. Unfortunately, we still had to listen to what sounds like a fleet of lawnmowers firing up when their generators kick on.

Where we really appreciated the advantage of the batteries were for about 8 weeks this past summer, when the sun was high, days were long and the weather was cooperating, we kept our inverter in "Self Supply" mode. The priority for power usage was Solar => Battery => Grid. The house was fully powered off the panels by day, After sunset, the inverter swapped over to battery power until we reached out minimum power reserve (I kept that set to 30% of battery power), then swapped over to grid power. For those weeks, even with the central AC running, we never hit that 30% minimum power. I'd catch it in the morning with the batteries in the mid-30% remaining power before the arrays would pick up the morning light and begin recharging the batteries and powering the house. Net: We were off-grid! Loved that!

We maxed out our battery cabinet, it set us back just under $23k installed.

[solardreamer]

but I don't really want to be a slave to servicing/managing on a daily basis.

Nobody wants to do that but given what's available you will likely need to check/monitor from time to time. Just look at all the forum posts of frustrated owners wondering why their solar systems is not working as expected. The reality of having your own power plant is that you become a power plant operator ... like it or not.

One of the real challenges with the new TOU and NM3.0 agreement is to have it make financial sense without adding a ton of really expensive batteries.

It's futile in general to expect break-even under 10 years with NEM3. CPUC just recently approved POCO requests to further limit the value of excess (solar & battery) energy exported to grid by only allowing it to offset the generation portion of the monthly electricity bill which is small. So, the change means you can't get fast payback even with batteries contrary to what the CPUC claimed when touting battery under NEM3. If 10+ year break-even is acceptable to you then solar can make financial sense under NEM3.


You can find Schneider inverter and cheaper batteries from places like AltE and Current Connected. BTW, the Generac PwrCell system uses the Schneider inverter.

[Rade]

It's futile in general to expect break-even under 10 years with NEM3.

Spot on. We figure we're in our house for the next 15-20 years, expect to break even perhaps as early as 8 years out, conservatively 12.

[CA_Paul_PV]

What is everyone's opinion on Tesla solution with string inverter + Powerwall3 vs Enphase micro inverters and Enphase 5P Batteries regarding the wiring and install?
It seems like there is a lot of extra components and wiring required with the Enphase solution vs the Tesla.

[solardreamer]

What is everyone's opinion on Tesla solution with string inverter + Powerwall3 vs Enphase micro inverters and Enphase 5P Batteries regarding the wiring and install?
It seems like there is a lot of extra components and wiring required with the Enphase solution vs the Tesla.

Don't really like either. A better combination could be Enphase iQ7's and Tesla Powerwall 2 which is a pretty common and proven combination. Tesla string inverter seems less reliable based posts I have seen but Powerwall is a better battery in terms of simpler setup and compatibility with multi-vendor solar systems. Enphase battery setup is more complex but the microinverters are more flexible and have a more reliable record than Tesla inverters.

[Rade]

What is everyone's opinion on Tesla solution with string inverter + Powerwall3 vs Enphase micro inverters and Enphase 5P Batteries regarding the wiring and install?
It seems like there is a lot of extra components and wiring required with the Enphase solution vs the Tesla.

Sorry, Paul, the answer is "It depends". Here in Rhode Island, we looked at all the regional installers and product vendors, and it came down to the warranty and long-term service / support. Tesla, here, has an absolute abysmal reputation for those who went that route, and no comprehensive presence in the region. In other areas of the country, it's a lot better. For us, the "Best of breed" was Generac. This is New England, Generac has a large footprint here (with propane and gas generators). Offered a long warranty on their solar components, fairly good customer service and (for me) most importantly, ONE number to call if there is an issue with any component. In your region, how do your vendors fare up?