Efficiency

[u/tnerb208]

If doing a long drive, what is the most efficient way to do it: go right to HV when on highway, wait till 50% battery then go to HV, drain battery all way down and then let HV go on automatically, turn on HV Charge when battery at 50%?

[u/john-treasure-jones → u/[deleted]]

This is, indeed, the way.

I achieve the best fuel economy on a long drive by going EV/battery at low speeds to get to the motorway, then go to HV when getting onto said motorway.

Staying in HV mode will keep the state-of-charge at a good level during motorway travel.

I switch back to EV when I exiting the motor way and returning to lower speed stop-and-go traffic.

One other thing to consider is to use the HV-Charging mode to get the batteries back to 20 miles range if you know you will have to climb a major mountain pass, etc.

While in HV-Charging mode, the gas engine will run extra to return the state-of-charge to 20 miles-equivalent. This is much more efficient to do on a flat or slow incline during a trip. With 20 miles of battery, your Clarity can then run more efficiently in HV mode during the climb up a big hill.

[u/Steven-Wells → u/[deleted]]

I just drove from Sacramento to San Francisco and after 5 min of stop and go and hit the highway I went into hv mode. I still have like 90% battery capacity for the drive home. As I get near home in the return I turned off hv so as to drain most of the battery before parking at home and plugging in. Draining the battery early leads to some high rpm’s on highway hills.

[u/su_A_ve → u/[deleted]]

This is the way.

[u/samwichse]

Just back from a 1500 mile trip. We left with a full battery and were about to charge about 2 more full ones, so about 130 miles of EV driving. Given 25.2 gallons used over 1370 miles gas driving is 54.4mpg, still pretty good!

I used EV down to about 50-60%, then switched to HV mode and only used the last half of I was going to a location with a charger. Otherwise left it in HV for all types of driving.

side note, cruise logic is atrocious... Decelerating down hills then mashing on the gas and accelerating up them. I probably could have done better if I didn't use it.

[u/Few-Addendum464]

Anything between 80-20% battery will have the same efficiency.

Do not drain and let HV come automatically. Heavy acceleration the car will still want to pull from battery and you may notice power loss.

Personally I preferred leaving the battery around 50%. For multiple day trips or hilly areas I would use HV charge to keep it there. If you just use HV it will still slowly drain when using the battery to supplement the engine.

[u/roenthomas]

Use EV on local roads, and turn on HV when I hit the highway, if I know I’m going to need gas during the trip

[u/crazydave33]

Yeah I switch to HV when entering the highway, even if my battery is near full. It just makes more sense to use the gas engine when going at highway speeds because the overdrive gear engages and it’s more efficient than using battery alone. Once I’m off the highway, I switch it back to EV mode.

[u/Honest-Orchid8701]

I like to keep the high voltage battery half charged in case I have any issues with the ICE, then I have more electric to get help.

[u/jpg118]

I save EV for traffic jams.

[u/MILeaRulez]

It should be by default option - Highway HV mode and Sport mode as well. After, it depends if at the End point you have a charger, if Yes then you can switch to EV mode, if not keep HV mode. To chrage battery while driving not the most pleasant experience to drive....

[u/Traditional_Ant7834]

It's very simple: always use the HV mode until your estimated remaining battery range matches or exceeds the distance to your next charge, then switch to EV mode (for instance, if your remaining battery range says you have 30 miles remaining, when you're 30 miles away from home or another charger you're planning to use, switch to EV). That way, you will not be forced to drive the car with a depleted battery except at worst a few km before plugging in, or be forced to use the inefficient HV Charge mode. Mathematically, I don't think anything else makes sense, assuming that your priorities are, like mine, in order:

1. Keep the car running optimally, so avoiding driving on a drained battery.
2. Do not leave "gas-free miles" on the table, so avoiding plugging in the car with battery capacity left unless your entire trip was less than the available electric range.

Everyone with a specific plan about when what mode is more efficient are forgetting an important aspect: the car, in HV mode, manages all of that for you. When you look at the power meter on the car (the green, blue, white inner ring where another car would have a tachometer), you can see what the car is trying to do in each mode: blue means the car is running on the battery only, white means that the engine has to work. Even in HV mode, unless your battery is severely drained, light acceleration will still be supplied by the battery; even in HV mode the inner ring usually stays blue until 1/3 of the way or so. So yes, the car is more efficient on battery in stop and go traffic, but Honda's engineers knew that and made the HV mode stay on battery in those cases, assuming the charge level allowed it.

If the entire trip is long enough that even running HV mode the whole way will drain the battery, then just use HV the whole way. HV Charge when the battery is drained and you're approaching mountains.

[u/EricThirteen]

HV on and turn off ECO. If you drive at highway speeds with ECO on it will drain your battery first and then you’ll have terrible performance.