Charge-Mode for Prius Prime

Wow. That's some serious praise.

 

I would add to @john1701a that CHARGE mode is an option we did not have before and worthy of experimentation, not a blanket condemnation. Let me share an example.

On a recent trip to Knoxville, on the way back I stopped at Whole Foods in Chattanooga for a biology break and plugged into Blink ... who nicked my card. I paid more for that charge than if I had used CHARGE. Which reminds me to put a comment in PlugShare:

• $0.68 for ~30 minutes, barely enough to cover the distance back to the Interstate.
• ~$1.00 of gas in CHARGE mode would have given ~20 miles EV range and a wider selection of food and service.

If approaching a dinner/lunch stop, enable CHARGE mode about 20-30 minutes out from the exit and use the EV mode to go to an upscale rest stop.

Bob Wilson

 

Yep, people understimate the value of the CHG mode... unless you're charging for FREE or at HOME, it's hard to beat the CHG mode ;-)

 

I'm not sure how to interpret OPs video without knowing how much fuel would have been used in regular HV mode

E.g., say regular HV mode would have been 60 MPG
Then fuel consumption would have been 5/6 gallons (0.833) for 50 miles

Instead 1.25 gallons was used to charge up the battery to 80% and travel 50 miles.
In Charge mode 5.6*0.8 kWh was put into the battery, using 1.25 - 0.833 = 0.417 gallons
Since a gallon has 33.7 kWh of energy, Charge Mode efficiency would work out to be (5.6*0.8)/(33.7*0.417) = 31.9%
That would be an impressive result for a generator, but likely inferior to just using the fuel in HV mode to move the car.

Or put another way, would you choose one gallon of gasoline or 10.75 kWh of battery energy ?

 

I've wondered this. My non-scientific experience indicates that by leaving some charge on the battery, I get better hybrid mileage than if I let the EV mode run down to zero miles (still ~25 or 30% battery on gauge). Even with 1 mile left, I get about 5 MPG better in hybrid mode than if no EV range left. Very odd.

 

I am new to this. I have just under 1000 miles on my new Prime. I have been utilizing the B on steep hills. It seems to keep the speed more steady than riding the brake. Plus it seems to charge more--according to the dash board graph--than using Drive and the brake. I really am liking the MPG!!

 

Have you tried using the two types of cruse control you have to get the same effect?

 

Usually in the city so not using cruise control. You say 2 types? Can you explain?

 

Normal type like on any non hybrid car and the radar cruise control(DRCC). You have both. Many use the DRCC in urban traffic as it can work all the way down to a stop. Slows you down as the car in front slows. Tries to maintain a certain distance to the car in front up to your maximum set speed. Lots good reading in that big book that came with your new Prime.

 

Oh. I thought there was something I was missing. I just consider it all the same. I always have the radar on. Yes, I have read the manual from front to back. Probably one of the few. However, I have slept since then...lol.

 

DRCC and "constant speed mode". The constant speed mode is like the old style cruise control. To set it, press the cruise control ON button and HOLD it in for about 2 seconds. Now you're in cruise without the radar control.

 

Hm... sounds like further study is needed on this...

 

This makes a lot of sense to me. warmup cycle = low-(est) efficiency + EV = high efficiency

Something to be aware of with dyna radar cruise control (DRCC) is, if the sensor(s) get covered sufficiently ( messy driving conditions ) the feature stops working to the drivers surprise ( at least the first time it happens ). Unless the ECO dash warning "Clean Radar Sensor" pops up in a timely way. It popped up for me 10 miles later in the driveway.

 

Lots of interesting arithmetic in this thread. But I did not see anything that dialed in the efficiency of the electronics at each transition: my Level 2 charger gets warm when charging at home - so there is energy loss. The DC-to-DC converter to charge the EV battery, and another converter to charge the tiny 12v battery give off heat - in fact, owners are warned to not block the cooling vents beside the back seats. More energy loss. In other electronics, I am used to 80-90% efficiency in a power supply . . . Does anyone have specifics to plug into these analyses? By the way, great discussion - love these forums!

 

Best *commuter* car for me, yes. And, much more responsible in terms of it's carbon footprint. But the "best car" of the almost 50 I have owned so far? My '95 BMW M3. Lightly modified, and enthusiastically tracked. But comparisons without parameters are like pulled pork vs. fresh-squeezed grapefruit juice - not exactly fair. ;~)