The Guess-o-meter (GOM) provides you with an estimate of the range available to you. The GOM updates its estimate (or guess) based on the energy consumption of the current and previous trips. Driving fast and accelerating hard and your GOM will show a lower figure, cold weather so using the heater will also affect this. A reasonable temperature of around 20 degrees Celsius and urban driving and the estimate will be higher. Based on a Nissan Leaf 2022 40 kWh, less than a year old.
So, roughly how wrong is the GOM?
The following was based on data when the temperature was about 15-20 degrees Celsius, no use of the heater or air-conditioning and a mixed driving usage, of urban (20-30mph) mixed with dual-carriageway speeds (60-70mph).
I took a reading of the mileage, GOM and percentage of battery remaining.
Battery Remaining: 20%
Distance Covered (since full charge): 113.5 miles
Guess-o-Meter (remaining range): 34 miles
80% of the charge got me 113.5 miles, so 113.5/80 = 1.4 miles per percent.
So assuming I used the complete remaining 20% of the range at a similar driving style, that would be 20 * 1.4 = 28 miles remaining.
So we’re talking 34 miles on the GOM vs. a 28 miles based on the consumption, that’s about 19-20% difference in real observed range and what the GOM is saying.
When I had a full charge the GOM said 170 miles, so assuming its wrong by 20%, then 20% of 170 miles is 34 miles.
So, finally, 170 – 34 = 136 miles of real range.
As a final check, at 20% charge, i’d covered 113.5 miles, let’s add the 28 miles I calculated from above and we’re at: 141.5 miles.
Essentially when it says 170 miles on the GOM, you only really get 136-141.5 miles.
Conclusion
So how wrong is the GOM? Based on my very rough estimates.
The GOM is about 20% (or a fifth) wrong, i.e. you only get 80% of the range it says (typically).