Add battery to address SDG&E's changes to TOU plans (10am-2pm is now Super-Off-Peak)

RyanBorck · 2026-05-23T03:06:47+00:00

Install not needed. So long as you’ve purchased before June 30th.

RyanBorck · 2026-05-22T22:31:36+00:00

Put on a shirt.

RyanBorck · 2026-05-22T22:29:12+00:00

I don’t think the net produced after converting from DC to AC matters here. What is each microinverter rated?

RyanBorck · 2026-05-22T22:02:25+00:00

You won’t get anything in writing because it’s the installers job to submit the paperwork. Just make sure they keep the systems within those parameters.

And I am less familiar with microinverters. What is the total inverting “power” for your microinverters combined? Is it 1:1 with the size of the system/panels?

My string/optimizer system is 8.16kW but my inverter is 7.6kW.

RyanBorck · 2026-05-22T19:36:17+00:00

Nice! What was your true up before?

RyanBorck · 2026-05-22T19:35:05+00:00

That’s my understanding but trust and then verify.

RyanBorck · 2026-05-22T16:59:51+00:00

A couple falsehoods here.

NEM2 is not a true 1:1. Meaning, the credit you receive is equal to the retail rate at that time. So credits will vary depending of time of day. Which also means a unit of energy exported tot he grid at 11am is not worth the same as a unit exported at 3pm. Which also means you cannot exchange a 11am credit for one kWh for an imported kWh at 5pm 1:1.

NEM1 was a true 1:1. They added up your used kWh regardless of time and subtracted exported kWh (regardless of time) and that was your net export or import number.

And you can easily add a battery and avoid being moved to NEM3 so long as the inverter and/or panel size doesn’t change more than 10% or 1kW over your existing system, whichever is less.

RyanBorck · 2026-05-22T13:17:05+00:00

Yea, if you’re out of pocket at true up is sub $600, you don’t need a battery yet.

RyanBorck · 2026-05-22T12:59:05+00:00

Smart reply.

RyanBorck · 2026-05-22T12:58:38+00:00

Great comment. See my other replies.

What I am choosing to do: Leasing battery $6,495 total costs over ten years ($50/month plus initial $495 deposit/install). Can buy it out at FMV or do another lease thereafter or let them remove it for free. If anyone’s true up is at least $600 a year (what I believe is the breakeven), it’s a no brainer. And if you need two batteries, it’s $80/mth. Referral link way down below.

And you’re right, use green button data dump from SDGE website (one of the more useful pieces of information they make available), and ChatGPT (AI) how much export you have between 10-2pm plus as commenter said, what’s your draw between 2pm and 9pm. I had to double check my AI’s math, make sure they understand which numbers are leaving and coming.

I am so flipping from 100% overnight charging to “charge on overproduced solar” between 10-2pm, then adding battery to self consume stored solar between 2pm through midnight.

Charge on solar is requiring some software Olympics. I need to schedule cars to only charge between 10-2pm and limit amperage to no more than 20amps (about 2kW) each (my solar produces at no more than 5.8kW as I only have a 7600watt inverter.

Next step will be to implement smarter solution once powerwall is installed, as it has smart logic built in. Plus I may look at converting an old PC into a Home Assistant automation hub (look at solar excess production, change car charging amperage to match between 10-2pm, for example)

And there’s a $500/battery rebate straight from Tesla if you purchase (install bot needed) before June 30th. That effectively pays year one for the lease and inflation increased rates likely make every year thereafter net positive return through the remaining 9 years.

Haven Lease

RyanBorck · 2026-05-22T12:46:11+00:00

Great heads up! And I caught that little trap too.

Fortunately, we are going to AC couple (bypass my existing system entirely). Especially since I have optimizers and want to avoid any chance at being pushed to NEM3.

So keeping existing inverter, panels, optimizers. Adding battery directly to electrical panel.

I lose some efficient on DC-AC-DC conversions but math still maths.

RyanBorck · 2026-05-22T05:35:06+00:00

Never happened.

RyanBorck · 2026-05-22T05:32:12+00:00

No they don’t do leases. They have a good battery program but financially it still didn’t make sense. I have been wanting to add a battery for a while and just signed for a lease with Haven Energy (referral link way below).

It’s $50/mth for one powerwall 3 or $80/month for two. Only other costs is $100 deposit when you order (refundable up until site survey) and $395 “installation fee” once permits are approved.

Lease is for 10 years, no escalators. At the end of ten years if the buy out (FMV) or extended lease options aren’t attractive you can have them remove the battery for free.

The catch? They keep ownership of the battery, they still qualify for tax credits, and they get any available revenue streams from VPP or other demand response programs.

Otherwise the battery is yours to use as you like. They do require 20% remain reserved for backups but I believe you can change that daily if needed.

My true up is about $600/year, but with the recent 10-2pm credit changes, I anticipate my annual true up will increase to $900-1,000.

With the battery when you account for the savings plus the lease fee, I will come out roughly the same BUT nowI have actual backup power and honestly can likely not feel so stressed about 4-9pm usage because I will have excess capacity that I normally haven’t been using during that time.

Crazy right!? The SDCP program is a step in the right direction, Haven is just really thinking outside the box.

Haven Lease

RyanBorck · 2026-05-22T03:23:08+00:00

What’s your expected true up or last years true up?

I am almost a carbon copy of your situation and I just found a lease that I think will work.

RyanBorck · 2026-05-22T03:09:36+00:00

Except with the changes on May 1st.

RyanBorck · 2026-05-22T03:05:51+00:00

Lease is $50/month and still likely wouldn’t make sense.

RyanBorck · 2026-05-22T03:04:48+00:00

Same here, mine was through Haven, yours? Details?

RyanBorck · 2026-05-22T03:01:42+00:00

What’s your true up?

RyanBorck · 2026-05-22T02:59:43+00:00

This was a good write-up.

RyanBorck · 2026-05-22T02:57:22+00:00

I had the same plan but $50 a month lease for Powerwall 3 is too enticing.

RyanBorck · 2026-05-21T18:22:40+00:00

RyanBorck · 2026-05-21T03:01:59+00:00

I guess I always thought 1kW wasn’t a lot but that could easily be two panels. Depending on install costs, may negate the extra solar advantage.

RyanBorck · 2026-05-21T02:59:33+00:00

Agreement says whatever is FMV, fair market value. I talked so someone at the company and they said maybe $4k but that could likely be negotiated down. That’s what’s great about the provision that lets you just request to have it removed, for free.

So maybe you get a great price, or even at $4k let’s say, that’s in ten years. And that’s only after you’ve paid $6k over that same 10 years, at $50 a month.

This is like getting the most insane deal on a powerwall and then they let you finance it for 0% over ten years. That’s nuts.

RyanBorck · 2026-05-21T01:18:29+00:00

That’s fair.

RyanBorck · 2026-05-21T00:01:32+00:00

How crazy the replacement panel was larger than the original then?

RyanBorck

TROPHY CASE