Energy Efficiency over time

[EVangelist]

In recent weeks both my wife and I though the GOM was dropping faster than when we first got the car.  Since it is only 4 months old, naturally we started to worry a little bit, like whether the batteries were OK (12 bars still showing though) or whether there was some other problem.

So I downloaded the latest Carwings stats and plotted energy efficiency over time, as a rolling average of the previous 100 km driven, to see if anything had changed in recent months.  I wrote an Excel macro to process the raw data to do this calculation, it's not something than can be done directly.

The results were interesting (attached).  Efficiency declined significantly between mid and late January, even though the regen rate was good.  Since then it's been on the improve.  Energy efficiency (green line) has bounced between 0.12 and 0.16, averaging out at 0.14.  The regen rate (blue line) is in a tighter range between 35% and 40%.

I can't put my finger directly on a reason.  Possibly we started to drive it a bit more aggressively as we got used to it.  Maybe there were times I forgot to put it into "Eco".  After sensing we were burning up the kWh a bit faster, it seems we are back to driving a bit more efficiently.  I don't think hot weather was a factor, we keep the car in a garage.

I'll update this graph periodically as a "pulse check" on how our vehicle is operating.

[Phoebe]

All sorts of things affect it.  Whether the terrain is hilly or flat,  whether a wind is blowing and in which direction and how fast are just 2.

[gabzimiev]

most likely because you need need pump the tires and wax the exterior :-P (and yes while joke but will actually affect range)

[EVangelist]

Mar 1, 2015 21:24:36 GMT 11 gabzimiev said:

most likely because you need need pump the tires and wax the exterior :-P (and yes while joke but will actually affect range)

What would you recommend as the optimum tyre pressure?  I've read here from some that tyres should be pumped to quite high pressure - higher than manufacturer recommendation.

[hieronymous]

Mar 2, 2015 7:57:32 GMT 11 EVangelist said:

Mar 1, 2015 21:24:36 GMT 11 gabzimiev said:

most likely because you need need pump the tires and wax the exterior :-P (and yes while joke but will actually affect range)

What would you recommend as the optimum tyre pressure?  I've read here from some that tyres should be pumped to quite high pressure - higher than manufacturer recommendation.

Everyone has an opinion on this, but that's all it is - an opinion. No two drivers drive exactly the same (driving style, roads, conditions, speeds); useful recommendations only come from track testing, and the manufacturers have already done that.
Under-inflation is much more dangerous than over-inflation (my Leaf wallowed around corners when I bought it - 4psi under-inflated), but over-inflation can result in a harsh ride and uneven tyre wear.
The Leaf already has a firm suspension to stop all that weight tossing about, but many owners try an increase up to about 40psi. Try small increases to see if you find the harder ride acceptable, but you won't see quickly any undue tyre wear.
I add 1-2 psi to to counter any over-reading by my gauge.

[gabzimiev]

Mar 2, 2015 7:57:32 GMT 11 EVangelist said:

Mar 1, 2015 21:24:36 GMT 11 gabzimiev said:

most likely because you need need pump the tires and wax the exterior :-P (and yes while joke but will actually affect range)

What would you recommend as the optimum tyre pressure?  I've read here from some that tyres should be pumped to quite high pressure - higher than manufacturer recommendation.

Nothing wrong with the manufactures recommendation just need to adjust it for temperature and extra weight. it's the recommended pressure for like 20 degrees C and a empty car so i add some PSI if it's hot or loaded. And try and check them every 3 months.

[kris]

Tyre pressure definitely worth checking since our Leafs lack the electronic tyre pressure monitoring system. One of ours looked a bit low the other day so I put a gauge on, 29psi on one wheel & 30 on the other 3. I'm ashamed to say it's the first time I've checked since we purchased 18 months ago. Pumped them up to the recommended 36psi, ride not noticeably stiffer.