PLEASE HELP! Home Charging Options for Prius Prime

That's why many point & shoot cameras rarely leave automatic mode. You have the option of choosing, and can indeed capture photos better, but are better off just leaving it alone in most cases.

btw, the "ONLY ON LONG TRIPS" is a kiss. It's a very easy to follow suggestion.

 

According the entry in the owner's manual, the EV button is there to prevent the ICE from coming on while shuffling parking spots, or the delay ICE operation so you don't disturb your neighbors with engine noise.

From Toyota statements, Charge Mode was installed mainly for markets where EV limited destinations might exist. Everywhere gets it because people also ask for it; that doesn't make it a good idea.

Judicious use of the EV button can help overall efficiency; same with Charge mode. But I suspect most people trying it will end up hurting their efficiency.

 

no doubt. the only reason they have it is because volt had it. they've become a me too, instead of a leader.

 

And it sounds like the only reason the gen2 Volt has it is because the gen1 had it, and not because of an actual need.

 

It takes about 30 kW to move a 1600 kg car up a 7% grade at 60 mph (27 m/s). If you mishandle the car and force battery recharging during the climb you may see something close.

 

I get 39.6kW. And the car weighs 1740kg, since it has four people and luggage. So that's 41.7kW. And it's above 3000m of altitude reducing available engine power by 25-30%.

Mishandle? I just set the cruise control at 60 (the speed limit), and that's it.

 

agreed, the whole thing is a sham.

 

Does your car have a carb ?

I calculated the vertical rise energy requirement:

60 mph = 29 m/s
-- about 1.88 m/s rise at 7%
Joules = 1.88 * 9.8 * 1600

Add another 12 kW or so for power draw on level ground at 60 mph.

That may be the problem. I get up to speed and 5 mph more before the ascent with high engine power, and then back off the fuel pedal a little the rest of the way. In an older Prius the car will rely on the engine when SOC is ~ 50-60% and the power draw is somewhere in the range of 20 - 50 kW. The range is approximate. As I said earlier, the 1.5L Prius takes driver effort to avoid SOC depletion on extended inclines, and it would not be surprising if your now 13 year old car has a substantially reduced pack capacity, giving you less room for battery use before the car goes into forced recharge mode.

In a Prime you will have a 70 kW engine, and if the traction battery was not depleted by EV driving before the ascent you will have ~ 3 kWh of battery reserve for the climb instead of ~ 0.1 - 0.3 kWh in your '04 Prius.

 

My car is a 2004 Prius.

 

Huh? There is about a 3% loss of maximum engine power per 1000' of elevation. The difference between a carburetor or fuel injection relates to the correct mixture, not to the lack of oxygen reducing max power at higher elevations.

I don't see the need for the charging option. Maybe if one knows of a long, steep, high speed uphill grade ahead, and knows that the engine isn't adequate. Otherwise, why? A gasoline engine is more efficient at wide open throttle. At part throttle power (efficiency) is wasted by pulling the intake air past the partly closed throttle plate. I'm defining efficiency measured as grams of fuel per horsepower-hour.

 

Yes, my mistake

 

What was the engine size in the Gen1 Volt ? Smaller than a 1.8L Prius IIRC

 

That makes no difference at all on a 7 mile long climb.

 

That's 41.5kW, using your numbers.

 

The gen1 had an off the shelf 1.4L, and the gen2 a 1.5L from a new engine family that was tweaked more for the Volt. IIRC, the new Volt is also a lighter car.

Mountain mode was for maintaining a higher SOC for climbing steep and long inclines, because the 1.4L was lacking in output and needed battery support in those cases. The mode could be used to charge the battery when the SOC was below that set limit. The new model doesn't have such power limits, so Mountain mode for that purpose isn't needed.

 

Yep, and this is my point as well, that it is probably true for the Prime except for corner cases or aggressive drivers on long climbs.

 

We'll see the first time I head up to the mountains after I get my Prime. Both sides of the Eisenhower tunnel approach and the East bound side of Vail Pass discharge the battery in my 2004 fully long before reaching the top, just at the speed limit. I hate that because, despite the fact that the engine has the power to maintain speed without battery assist, it doesn't have the power to accelerate at any reasonable speed. For example, if someone pulls out in front of me and slows me from 60 to 30, it can take 60 seconds or more to get back to 60 on engine alone at full throttle, whereas with battery available, that will take less than full throttle and only around 15 seconds.

 

Here's evidence of the battery range from my trip home tonight. All on battery with a couple of miles to spare on it.

 

you're running out of gas though. Quick question, was that all EV on flat surface or was any downward driving on hills involved?

 

does average mpg of 199.9 mean the engine came on? what was your average mph?