Possible to add Powerwall to older Solar system?

[RayB]

Hello - I'm wondering if anyone else here has had a similar situation as us...

We are located on the SF Peninsula (Redwood City area) and are looking for a home backup system, which made us think about the Tesla Powerwall. Back in October 2007, we purchased (not leased) a smaller sized solar system from Solar City (now part of Tesla). 16 panels (2,840 W), see attached for details. It's suited us well, as we (two of us only) have no pool, or air conditioner.

We recently purchased a Tesla Model Y, and charge the car during the night. Since we don't drive to an office each day, we don't need to charge it up every night, but even so, we see our annual True-up amount owed to PG&E will be more than previous years.

We would like to better understand the following...
1) Is it possible to add a Powerwall to our current system?
2) If needed, is it possible to increase the amount of Solar panels we have or swap them out for more efficient panels? This will increase the energy generated, and can be used to draw power from, and store excess energy in the Powerwall and act as power backup during PG&E power outages.
3) Would updating the inverter help at all? Sorry...I'm not very well versed on how this all works....

Should we work with Tesla Energy directly, or use one of their partners? Any recommendations?

Thank you in advance.

 

[Kbreezy92]

Hello - I'm wondering if anyone else here has had a similar situation as us...

We are located on the SF Peninsula (Redwood City area) and are looking for a home backup system, which made us think about the Tesla Powerwall. Back in October 2007, we purchased (not leased) a smaller sized solar system from Solar City (now part of Tesla). 16 panels (2,840 W), see attached for details. It's suited us well, as we (two of us only) have no pool, or air conditioner.

We recently purchased a Tesla Model Y, and charge the car during the night. Since we don't drive to an office each day, we don't need to charge it up every night, but even so, we see our annual True-up amount owed to PG&E will be more than previous years.

We would like to better understand the following...
1) Is it possible to add a Powerwall to our current system?
2) If needed, is it possible to increase the amount of Solar panels we have or swap them out for more efficient panels? This will increase the energy generated, and can be used to draw power from, and store excess energy in the Powerwall and act as power backup during PG&E power outages.
3) Would updating the inverter help at all? Sorry...I'm not very well versed on how this all works....

Should we work with Tesla Energy directly, or use one of their partners? Any recommendations?

Thank you in advance.

For questions like this, you should really just call Tesla or the installer directly.

From my understanding you can get powerwalls for any reason (such as charging straight from the grid or just backup in general). But to pair with solar, you need at least 4kW for one panel, 8 kW for two panels, etc. Otherwise with a 2 kW system, it will take a while to charge the powerwall.

Also Tesla does not add on to existing panels that aren't built by them. They only install new systems because of warranty issues.

 

[arnolddeleon]

Yes, it should be possible to add a Powerwall to your existing system. I added Powerwalls to a fairly complicated existing set of systems (one owned, one leased from Tesla, nee Solar City)

Yes, you can buy more solar. Probably the easiest path to more solar if you have the roof space. Almost not worth touching the existing system unless you are roof space restricted.

A newer inverter might be a tiny bit more efficient but it won't be worth it unless your current inverter is dead.

Tesla Energy has some of the best solar prices. They're not the most flexible/customizable but when they work their watt/$ is pretty hard to beat.

 

[patrick40363]

Yes you can add a powerwall. If you increase the size of your system you will knock yourself off the E-6 program you are on.

 

[cassiopeia]

Hi RayB,
I’m your neighbor (live in Emerald Hills) and had an existing, non-Tesla solar system. I just added Powerwalls a little over a month ago, so yes, it is very possible. They have a process where you work with them to understand your needs and then fill out an extensive site evaluation that includes photos of your system to make sure that they can work with it.
Good Luck!

BTW, it turns out I completely misunderstood some things about PGE billing and now realize that the Powerwalls will take a VERY LONG time to pay for themselves, however, given that the real reason I got them was to avoid the power shutdowns, I’m quite happy with them anyway.

 

[getakey]

one big surprise is that adding PWs to existing solar triggers a True Up bill out of your cycle
All evens out in the end, but you need to expect that

 

[RobbL]

Very helpful information provided already which matches my experience. I’m in the Oakland Hills, have a 2.5 kW system installed by Solar City about 8 years ago, and just added another row of panels and a Powerwall a few months ago. I wanted to work with Tesla, but they couldn’t install until sometime in the fall and they had no SGIP rebates. Instead, I worked with Infinity Energy who did an excellent job, and all is working well. Definitely worth giving them a call and getting a quote. PM me and I can give you more contact info.

 

[JPP]

We have 16kW of SolarCity (now Tesla Energy) PV solar on a 2013 Power Purchase Agreement (20 year plan). Just had Tesla install 2 Powerwalls (long convoluted story--not relevant here). No issues adding Tesla installed PWs. And, yes, you get a true up but should not be swapped from NEM1 to NEM2. You might want to revisit your PG&E rate plan and see if there is a better one. YMMV.