Hypermiling the i-MiEV

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I was asked by one of our new members to summarize my current approach to hypermiling and thought I'd post my answer to him -


Need to separate the hypermiling discussion into three categories:

1. City and suburban driving
Featherfoot, always accelerating gently. ECO mode is good for this. Plan ahead and coast whenever possible (I have the car in N as much as 30% of the time if I'm hypermiling) - cars around you won't even realize you're doing this. Pay attention to the lights and traffic way ahead of you and coast if you can. When needing to slow down, play with the shift lever, adjusting between N-D-ECO-B to smoothly slow down and only apply the brake when the car is below about 9mph when the regen cuts out.

2. Highway driving
Keep your speed down to 55mph (in the right lane!!). If possible, get behind a truck and draft - don't need to be really close to get the effect. Being in the lane to the right of the truck's rear also works, but not as well. Coast whenever possible: play with the shift lever between D and N, popping it into N on every downward undulation of the highway (e.g., coming down an overpass, and don't push the accelerator to keep your speed constant when going up the overpass). Beware of headwinds, in which case really do try to latch onto a truck.

3. Mountain driving
Even though our i-MiEVs are very sprightly and can zip up the hills better than many cars, don't do it. Keep in the right lane and follow some trucks going up the hill at 30mph and just go really easy on the accelerator. Going downhill, it's a matter of fluctuating between D and N and keep your speed down to minimize aerodynamic drag and maximize regeneration - there's a long technical discussion on this forum as to which is better.

It really requires patience and willpower to ignore the cars around us if we're serious about it, always remembering to be in the right lane. In California, the slowest speed allowed on a freeway is 45mph unless climbing - I do not go that low, but if in trouble it really is much better than 55mph. Often it's better to avoid the interstate and stick to smaller roads and lower speeds if you really need the range.

Sadly, external influences prevent us from driving efficiently:

In city/suburban, when you're coasting because you see a red light 1/8-mile ahead, there will invariably be yahoos who will pass you, jump into your lane, and stop in front of you in what would have been a smooth brakeless transition as the light turned green.

In mountain driving, when you're trying to optimize your downhill run by keeping the speed down, those 18-wheelers breathing down your neck make it impossible and possibly deadly - best to get in behind one.

That said, nowadays I'm a leadfoot and very rarely hypermile. When I started out with the i-MiEV I came from the Gen1 Honda Insight culture where fuel efficiency was king (my lifetime was over 77mpg over 95K miles!). Nowadays, I rarely am in a situation whereby I have to hypermile and thus have reverted to my teenage leadfoot ways... :)

The other non-hypermiling significant effects are:

HVAC - avoid using the heater (use the heated seats) by dressing warmly and only use the HVAC to demist the windows with the combination of heat and a/c, intermittently if possible. Pre-heat the car before every trip while it's plugged in at home using the Remote.

Tire pressure - keep as high as you are personally comfortable with.

Rain and snow and headwinds - make a big range hit on the car, so plan accordingly.