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A year of posts about this system — payback maths, solar scoreboards, a metric I invented to keep myself honest — and the question underneath all of them is simpler than any of it. Am I actually winning? Fair question. One word answer, then the evidence: yes.
The timing. The charge planner's whole job is choosing when to buy, and in July it bought 9p under the market — 13.8p a unit against a 22.8p average, in the dearest July Agile has offered me yet. The battery itself filled at 6.5p. My control group is July 2025, when I bought without looking: dead level with the market. This is a learned skill, and the machine learned it.
The bill. 56p a day this July against 99p last — down 43% while the market went up 11%. Beating a falling market is luck. Beating a rising one is the hard version.
The trend. When I picked the cheap windows by hand I captured about 5.3p a unit below market. Since the planner took over: 8.3p, and climbing — with a commit log that tracks the improvement month by month. This is a slope, not a plateau.
The estate. £246 ahead of the price cap in year one. 29 days so far this year when seven panels on a garden fence out-produced my entire grid draw. A battery that will die of calendar age long before it runs out of rated cycles.
Now the honest proportions, because winning needs a denominator. July's entire grid bill was £15.71 — the planner's cleverness saves pounds, not fortunes — and the £2,203 the system cost takes years to walk back. But even that number is losing gracefully: my first winter estimate said eleven years, the lifetime average now says 9.3, and at the last two months' run-rate it is closer to 8. May proved the market can simply withhold the spread, and no amount of code can buy a trough that isn't there. Winter will do to the solar numbers what winter does.
But here is the part that compounds. Most people with a battery own a gadget. This one measures itself, catches its own bugs, publishes its own evidence, and gets a little cheaper to run every month it is worked on. That is not a gadget. That is a strategy with a paper trail — and the paper trail says yes.