When the Powerwalls Went to Zero: Turning a Tesla Recall Into a Home-Energy Upgrade

On September 2, 2026, we woke up to an unwelcome message in the Tesla app:

“Powerwall Disabled — Your Powerwall will be replaced.”

Finding Dad's Mille Miglia Photographs

For years, I knew that my father had been in Italy during his Army service in the mid 1950’s. While cleaning the family home this past year, I’ve had to sort through boxes and boxes of photographs, slides, family albums and ephemera from the Marstons and McMillans. 

Tucked away among old family photographs and negatives, was a small collection of 3x5” black and white pictures of old sports cars in what looked like a race.

When I started RaceCoach, my goal was simple: make better use of the telemetry I was already collecting during autocross.

Like many drivers, I was recording every run with RaceChrono Pro, a RaceBox GPS, and OBD data. I had plenty of information, but only a few minutes between runs to decide what to change. Looking at graphs and numbers wasn’t helping me answer the most important question:

What should I do differently on my next run?

That question has gradually changed the entire direction of the project.

The Original Idea

Progress at the PCA Zone 7 Autocross Weekend

I asked ChatGPT to summarize the results of the weekend as it related to the programming work we’re doing in RaceCoach.

The July 11–12, 2026 PCA autocross weekend at Salinas provided a useful test of both my driving and the RaceCoach analysis workflow I have been developing.

While at an event, RaceCoach outputs both a grid and latest report of the comparisons run (1 v 2, 2 v 3) done via run_analysis from the command line.

To read the background on this project, read through the repo’s files here:

https://github.com/peterm95018/Racecoach/tree/momentum-recovery

The grid report is here:

RaceCoach

This is an early draft of the project description. It has morphed during development so some of the points below have been altered.

RaceCoach started off as a personal autocross telemetry and coaching project built to help me get faster between runs. What is has changed into is a coaching engine that does this:

Observe → Diagnose → Coach → Improve

The goal is simple: after each run, RaceCoach should answer one question:

Well, it is April 2026. Here’s a summary of the events that have transpired.

2026

• 3/9/26 Laguna Seca GGLC 4 20 min sessions
• 4/6/26 Sonoma GGLC 4 20 min sessions (PB 1:59.07)

2022 Days (7)

• 3/5-6/22 Thunderhill East 
• 4/12/22 Sonoma Raceway
• 5/25/22 Laguna Seca 
• 5/26/22 Laguna Seca
• 8/26/22 Sonoma
• 9/28/22 Lagua Seca (PB 1:47.20)

2021 Days (11)

After hemming and hawing and interating with ChatGPT on various models, I bought a Specialized Levo Comp Alloy gen 3. Cycle sport had a few left in their inventory and had dropped the price to about half of MSRP and built it with an upgraded drivetrain and brakes.

I took it out for its maiden voyage and am continuing to study all its settings and setup options.

Letter from May 20, 1945

May 20, 1945

Dear Buster:

At long last the letter I've promised for so long.