Aloha, I purchased a 2018 Prius Prime 4 days ago and according to my gas gauge I’ve used a quarter of a tank driving maybe 45 miles a day. Caveat is I live on a mountain at about 3600 feet and work at sea level. I’ve been driving in “B” down the hill and charge mode up the hill. The first day I fully charged the battery before returning home and ran out of electric juice extremely quickly between 5 & 10 miles into the drive. I’ve been watching a lot of YouTube videos about this car, and realize I’ll learn more through experience. Several posts I’ve read imply that the gas gauge is notoriously inaccurate so I signed up for fuelly to help me track. Other than this glitch I think I’m falling in love with this car.
congrats! i think you're fine, but i would not use charge mode going uphill. that will kill your mpg's. in fact, don't use charge mode at all, unless you need to run on electric for some odd reason. also, running electric uphill is not going to be very efficient. all the best!
I agree with Bisco. Stop using charge mode. Also, I am not too familiar with B mode. You might want to try expirementing driving down the hill without B mode and see if you get better EV range or mpg on your commute to work. Just start braking as lightly as possible as early as possible and I think you might charge the battery even more and end up using less electricity and/or gas. Also I am not sure how far you actually drove to use up a 1/4 of the tank. If you drove all 4 days at 45 miles a day, that's almost 64mpg. If you only drove 1-2 days and fully charged the car each time, then maybe there is an issue. If you are getting close to 10 miles of range going up a steep grade, that may not indicate a problem. It takes me 10% of my range to go 1.3 miles with a 234 ft elevation gain at 35 mph. That's about 180 ft elevation gain per mile, which is fairly similar to your average elevation gain of 160 ft per mile. If you were going a lot faster than 35 mph, I think it would be perfectly normal to get well less than 10 miles of range on a full charge, especially if that part of your drive was as steep or steeper than the average elevation change for your entire trip. In contrast, I can drive 35 miles at 57 mph without any gas with an 800 ft drop in elevation. Slope, weather, tires and speed makes a huge a difference on efficiency for this car.
One other thing - due to the elevation, if you were running the heater at all it will drop your EV charge level faster than just about anything else.
Mahalo for the info. All the math makes my eyes cross. I’ve only fully charged once. A major portion of my drive is a highway and I’m definitely going faster than 35 miles an hour. 64mpg is awesome! Thanks your response makes me feel reassured. Have a great day!
Did you use the equivalent B-mode (D-2 or D-3) on on the other cars you've owned on the same commute? I haven't had any issues with my gas gauge and it's pretty accurate. I know people with gen2 and gen3 had issues, but they're much older cars with a bladder tank. Placing the car in 'charge mode' while going up steep grades will rob the power-train of power need to climb the grade. Using charge mode or locking the cruise control speed down hill would put more power into the traction batteries. Traveling up steep grades will also prematurely deplete your traction battery. Your not going to get the EPA rated 25 miles in EV mode climbing steep grades; in fact it messes up the onboard CPU calculations. On day trips up to Lake Tahoe and back, sometimes my calculated EV shows 25 miles/KwH - my normal range around town, on the flats is 3.8-4.5 mile/KwH. I don't baby the car or drive like grandma either. That's been my experience. YMMV.... PS: USE your A/C, traction battery pack cooling air is being drawn in from the cabin. So if your cabin is 85F, the air cooling your traction battery is at least 85F.
