I’m building WattsMyRange — an EV app for real-world range estimation, battery health and efficiency tracking
One thing I’ve been thinking about as an EV owner is how much we rely on the dashboard’s estimated range, even when actual efficiency changes with driving conditions.
wattsmyrange.com
So I’ve been building WattsMyRange, an app that uses recorded driving data to help EV owners understand their real-world efficiency, estimate usable battery capacity, and make more informed range decisions — without requiring an OBD scanner or proprietary OEM APIs.
Here’s what it currently offers:
1. Range Estimator
Estimate how far you can travel using your current battery percentage and working efficiency. You can adjust the efficiency in Wh/km to see how the estimated range changes, with a configurable reserve to avoid depending on the last few kilometres.
2. Battery Health Estimate
Estimate usable battery capacity and state of health from accumulated real-world driving observations, with confidence levels that improve as more qualifying data is collected.
3. Can I Reach?
A practical feature for estimating whether you can reach your destination with the available charge.
4. Real-world Efficiency & Drive History
Record driving data and build a longer-term picture of efficiency across city, highway and mixed driving.
The idea is to get more useful insights from ordinary driving data rather than needing specialist hardware or trying to interpret raw BMS readings.
Battery capacity and health figures are estimates, not diagnostic-grade measurements, and their reliability depends on the quality and quantity of the recorded data.
I’d genuinely like feedback from EV owners:
Which of these features would you actually use?
Would you trust a battery-health estimate built from real-world driving data?
What’s missing that would make an app like this useful to you?
I’m building and testing this independently, and I’m interested in honest feedback from the EV community.