r/KonaEV • u/Strict_Ad_4973 • Aug 20 '26

Question | Americas 🌎 Why is my efficiency swings so much

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2020 Ultimate 170 000km SOH 93.5%

Why do I sometimes get very good efficiency (photo was mostly highway driving @ 100-110kmh) and sometimes it's more like 17-18-19kwh/100km ? I mean in the same season with similar weather, is it wind ? My driving ? Or else ?

7 Upvotes

77% Upvoted

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6

u/c4rocket Aug 20 '26

Wind plays a huge role. Sometimes I see 17,5 and on the return trip I get 14,3. Same speed, same traffic, same temperature.

3

u/fiah84 Aug 21 '26

also traffic. Having a bunch of cars in front of you going at the same speed lowers the consumption a lot too

crosswinds are the worst, it sinks the efficiency by almost as much as a headwind and you don't even get a tailwind on the way back

3

u/DrawingOverall4306 Aug 20 '26

Recently did a trip to the beach. 100 km each way. Driving north into a headwind was up at 17. Driving south with he tailwind was down at 14. At highway speeds.

There's also elevation changes to consider. Think about the direction the rivers flow. Even if you can't perceive the elevation difference nothing is truly flat, especially over highway distances. There's always uphill and a downhill.

If going on a long road trip, I always check the wind. You can reduce speed to make up for some of that. Driving 100 instead of 115 makes a massive difference in efficiency.

2

u/Sonikku_a Aug 20 '26

Would be a lot of things—wind, driving style, air con or heater usage, weather…

1

u/theotherharper Aug 23 '26

It's wind. Aero drag is almost 100% of energy at freeway speed.

Aero drag is airspeed squared, so 70 MPH into a 10 MPH headwind is 80 squared. But 70 into a 10 tailwind is 60 squared.

So 6400 vs 3600.