Zonneplan formula in DESS is incorrect

Q&A and troubleshooting DESS
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1

I think the Zonneplan formula in DESS is incorrect, it gives the formula (p+0.01653+0.1088)*1.21 while I think it should be ((p+0.10154)*1.21)+0.02

2

I agree that Victron’s standard formula is incorrect.

I use this: (p*1.21)+0.02+0.12286

Then the price on Victron is exactly the same as in the Zonneplan app.

3

There is (an attempt to keep) a list of updated formulas on GitHub:

I say attempt because it’s mentioned on that list that tibber (NL, DE?) will switch to 15 minute pricing per June 2025 which I know has been delayed to September (at least).