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SInce I switched to driving EVs, I've become SO conscious of both Road gradients and different Road surfaces.
Inclines can quickly sap the battery at quite a rate, but has anyone noticed the apparent effect of Road surfaces?

The A41 has recently been re-surfaced with a rough surface between Hemel Hempstead and the M25. At 65 mph in my Ampera, it seems to work through my precious kWh at quite a rate - but I can speed around 10 miles on the northern part of the M25 hardly using any power at all..... Anyone else noticed this effect?
 

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Can't say I've noticed it but speed seems to be the biggest difference. Above 65 it drops considerably.
 

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Both are a factor. And in terms of road surface, wet roads will cause drag too. It's noticeable in heavy rain. Wind too... in fact that+speed are perhaps the biggest factors, but at least good feedback helps in adjusting driving according to range (I'm in a leaf)
 

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You need to make sure you have AB rated tyres, I hope soon the Michelin EV tyres will soon be available to all EV's as mine tyres are AA rated, as I think it's selfish of Michelin to make a deal with only Renault, as at the end of the day it's about saving the world and making it a better place for our kids, if every one got 10% better range, the more miles everyone drives on electric the better.
 

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Bridgestone Ecopia EP001S are already AA rated. My tyre fitter is a Michelin dealer and he couldn't believe it!
Bridgestone claim a 16% rolling resistance reduction on OEM Leaf tyres Ecopia 150s, they also claim an 11% improvement in wet braking. Having fitted only 2 so far I can tell the difference. They are slightly more harsh a ride though which you only notice on day 1. Just done 360 miles on motorways at 70 indicated and 60 indicated on A roads and at 4.2 miles per kwh:). Looking forward to fitting 2 more.

AS far as O.P. is concerned, it makes sense that rough stone chip surface would use more energy, more noise is more energy lost and any small pointed objects like stones require the tread rubber to deflect more and there will be little energy recovery from that other than in friction and heat. Another way of looking at it is that it will cost energy wearing the road surface smooth. Of course in proper road construction that is done by a proper road roller but surface dressing is all we get in most of rural England where we are meant to do 20mph and roll the road for the council and then fix the broken windscreens and paint chips:mad::rolleyes:.
 

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Maybe we should have altimeters fitted to our cars!
There is a page in the GPS that will display current position including elevation above sea level. It responds quickly enough to show gradients in real time.
There is a local stretch of the A3(m) that surprised me by being slightly uphill even though it appears downhill.
One of the biggest effects on MPW seems to be rain. The other is air temp. Looking back on Carwings my power useage was .25 to .27 kw per mile during the rainy season, it improved once the rain ceased, and dropped back again during the rain around Easter. During the warm dry summer months i normally attained .21kwM . Power usage was measured against a regular cross country journey with minimal variables.
 
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