More EV=higher mpg=lower battery longevity?

In Gen4 there is more EV time because the battery and the power electronics are more efficient, that is they convert more electricity into torque at the wheel, than heat somewhere else.
The batteries in the Prius have been used in a conservative way (i.e. never charged to 100% and discharged to 0%) exactly to avoid lifetime charge/discharge lifetime issues.
In case of NiMH like the Prius 3 and the Prius 4 sold elsewhere than Japan and USA (in EU only the NiMH version is sold - why it is not clear), the technology is extremely well established. Some Gen2 Prius have done hundred of thousands of miles (see taxis), on the same battery.
For the Li-Ion versions sold now on the Gen4, and BTW also in the Prius v/Alpha/+, Toyota has been testing Li-Ion batteries and strategy of usage for quite some time (about 5 years), before selling them actively on the market.
I would not really worry about the battery lifetime on a Prius.
BTW, in the USA you have extremely generous warranties lasting 5+ years on hybrid components, if it ever would fail, they will have to change it under warranty.

 

In the US, per the 2016 warranty and maintenance guide, the hybrid system is warranted for 96 months or 100K miles.

 

I'd say that is plenty of time to use the car beyond its useful life. If the battery fails after that, it is really worth to get a new battery? For sure yes, unless in 8 years we will probably need to drive automated cars and full electric.

 

Forcing the EV mode limits the computer's ability to choose the best way to make power, I do not recommend it for general use. (Save it for moving a car in a parking lot, or sneaking home late without waking others) However, in many cases, the computer will use EV as the most efficient way to get power. Letting it do so will not negatively effect your car.

As you are in California, (California, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island and Vermont are full CARB States for a 2016 model Prius. The 2014 list of CARB States in the US | PriusChat ) your HV battery has a 150,000 miles ten year warranty, not pro-rated.

With the exception of Eco which alters A/C use, the Eco, Normal, Pwr modes are User interface buttons, they do not choose how the car runs, they choose how it interacts with your right foot. Pwr mode makes the throttle twitchy initially and slows it down near the floor. Eco is the opposite, you have to push farther for more power initially but is abrupt near the floor. Normal is the most linear. (None have any effect in cruise control)

 

can you explain 'battery to run power mode' statement? never heard of it.

 

The computer on the Gen 4 will override the forced EV selection if it disagree with the driver's demands, therefore, it cannot be forced into EV.

 

Hmm.... I bought mine in CA and my dealer told me 8 years or 100k miles when I made the purchase. It would be nice to have a longer warrantee.

 

8 X 12 = 96

 

cali is 10 years, 150,000 miles on hybrid components. this does not include the ecvt., but the battery is usually the biggest issue.

 

have you heard of pulse and glide?

 

that is a plug in thread, irrelevant to lift back. power/normal/eco modes simply re map the gas pedal so it takes more or less pedal travel to accomplish the same thing. you may feel like the engine comes on more in poet mode, but it's only because you aren't pushing the pedal as far. the only other difference is that hvac is suppressed in eco mode to save fuel.

 

exactly. that will get you the best mileage when done properly. it's not easy to hold it with no regen though, usually i have to stay a bit to the right so it doesn't slip into regen, which kills your mileage.

 

If you are thinking using EV will give you better overall mileage, think again. Unless you have a PIP or Prime, which you can charge by plugging in, you have to replace the charge you use in EV mode by running the engine mostly. You -can- charge the battery by descending a long hill, but you need to use a lot of fuel to get to the top of that hill. So the inefficiencies of charging by running the engine come into play. It has been estimated on this forum to be about 50%. That is, about 50% of the energy you use to charge the battery with the engine can be reused to power the car later. That's a lot, considering the engine alone can only put about 35-40% of the energy in fuel to the wheels, but that inefficiency also applies to charging the battery.

The most efficient way to drive a Prius in a safe manner is to use a light foot on the accelerator, let the car figure out how to utilize the system, and relax. In either "eco", "normal", or "power" mode, depending on your taste for accelerator pedal response.
To get even more from the car read up on "hypermiling". In my opinion, this type of driving is not safe for regular use in traffic, but rather to set bragging points and/or contest numbers.