Honda CRV vs 2020 Prius Prime for trip to Rocky Mountains

Depleting it on the uphill ought not be a problem.

 

Unless one is going truly off-roading in the rockies, the Prime seems like a no brainer UNLESS everything you're bringing won't fit. A test fitting of everything now should answer that question. Don't forget room for possible extras obtained along the way.

Finally: is a spare tire important?

 

The spare tire is likely important if leaving paved roads.

 

I live near Denver, and I drive my Prime all over Colorado. I also have a 4runner, but since buying the Prime I'd rather drive that everywhere except rough dirt roads.

I've driven all over Rocky Mountain national park. There's nowhere that's "off the beaten path" in the park. All the paths are thoroughly beaten, and then beaten some more for good measure.

I've driven it up Old Fall River Road which is a scenic dirt road in the park. There were a few large ruts which take careful driving to get over, but the Prime was perfectly capable of doing that road.

It does great at altitude. You'll hear the engine a lot, but since the electric system is always ready to provide a boost, you'll always be able to accelerate if you need to. Highway passing will take a while, but that's no different than anywhere else with this car. The CVT is an advantage, because traditional automatic transmissions can be limited by gearing. Second gear usually runs out around 65mph (they have to optimize that 0-60 time, I guess), and then there's not enough power left to keep accelerating uphill in 3rd.

The most charge I've regained on the way down a mountain is about 80% coming down from Mt. Evans, and I think I hit 90% last time I drove home from RMNP, but I started with about 10% at the top. On higher speed mountain passes like Fremont pass you won't gain as much because the battery can only take charge at a certain rate. The engine will come on, but a lot of charge will still go into the battery. B mode for Regen works best in EV mode, so try to save some charge for when you reach the top of a pass. In HV mode it always runs the engine which is annoying.

Charging stations are lacking, especially in the mountains. But it charges so slowly it's not usually worth waiting.

 

Neither. If you plan on passing anybody in the passing zones you're going to need a turbo or a supercharger because the air is so thin. Naturally aspirated engines severely underperform in Colorado so much so that you won't be able to even pass anybody. Neither of those cars are going to work over there. My advice is fly in and rent something with a turbo.

 

I wonder how many Colorado residents would believe this.

Yes, compared to sea level, naturally aspirated engines do underperform at those elevations. But so do everyone else's naturally aspirated engines, which is the great majority of them. So it is still a fair 'fight' against the other vehicles. Even when passing.

 

There is a limit to how fast and how long the battery can charge. The limit is lower as the battery gets more full. For example cruising down a 6% grade highway mountain pass at 65mph requires around 17kW of regen in B mode to maintain your speed. That's a lot more power than the normal level 2 charging rate of 3.3kW. So at a certain point, the car will spin the engine (using no fuel) to waste energy with engine braking, like a non-hybrid would if you downshift. If you can avoid it, you can get more "free" energy into the battery.

 

All modern cars cut off fuel to the engine while engine braking. So it's just spinning, wasting energy as friction. It's like pulling the cord on a lawnmower that won't start, but in this case the fuel is shut off so it's intentionally not going to start.

I haven't found the best strategy yet for maximizing charge gained on long descents. Going slower is probably the most reliable way. At 65 mph the car might need to dissipate 17kW into the battery, but at 45mph it's more like 12kW, and the battery can accept that for a lot longer. My best trips for recovering a huge amount of energy are on 35mph and 45mph roads.

B mode in EV mode is pretty good at getting energy into the battery. If you don't want to overthink it, just do that. Even if the engine comes on, from what I've observed most of the energy is still going into the battery.

If you ride the brakes, the car will still send energy into the battery first, so it's not much different than B mode. Eventually the engine will still come on. If you you alternate between braking and coasting, sometimes you can keep the engine off longer, but you'll probably waste more energy as friction in the brakes. I'd suggest just using B mode so you don't overheat your brakes.

Once the engine starts, it won't stop until it warms up (which does waste a little gas, but it's very minimal). The only way to stop it early would be to park and turn the car off.

 

If you slow your descent, you'll eventually hit a rate where the car can convert & store all of that energy, at least until the battery is full. Because the charge rate drops off as the battery fills, this means you would be slowing down as you descend the hill. That's not really friendly towards traffic, so the first thing to realize is that "best strategy" has lots of possibilities and several contexts.

Second, don't get other drivers mad at you. Just don't. No fuel savings is worth that.

If you haven't already discovered it, shift the car to B mode on those long mountain descents. This tells the computer that you expect to be going down a long hill, and the computer can take this into account. It will charge the battery at a nice leisurely pace and divert excess energy into spinning the engine as needed. Importantly, the car won't try to "run away" and you'll have little if any need to hit the brake pedal. It improves your chances of hitting the bottom of the hill with a battery that is A) full and B) cool enough to use at full throttle for climbing the next hill.

The best way to minimize engine braking is to reduce overall speed but again, trying to eliminate engine braking may force you down to a speed incompatible with traffic. You're going to hear that sucker, no way out of that.

 

As they say a lot here, just drive it. The car pretty much takes care of itself. As @m8547 and @Leadfoot J. McCoalroller already advised, use B mode on the steep hills to help control speed. Sometimes B slows more than you want so it takes a touch on the accelerator pedal. If the battery gets too full or hot, the engine does not "come on." It turns into an air compressor that is powered by gravity and the weight of the car. No fuel gets used, as they already said.

Don't worry. Don't overthink. Do enjoy. It's probably a good thing I don't live close to the Rockies (or Cascades, or Sierra, or etc.). I would be sorely tempted to spend all my waking hours just driving this amazing Prime through the mountains. It's almost as much fun as a motorcycle, but in a different way.

 

How long have you been married ?
Regardless of the circumstances, it ALWAYS seems to be my fault !!!

 

The best strategy is to let the CAR take care of itself......and not worry about the engine sounding like a jet plane about to take off.
It is designed to do that.
First, the battery charging takes hold, which doesn't really supply much drag on a steep hill.
Pretty sure that the cruise must be engaged OR be in B mode to get max. charging.

Then the gas engine compression braking activates which uses NO gas.....or very little.
Sometimes that even isn't enough and a LITTLE intermittent braking is needed too.
YOU SHOULD NOT RIDE THE BRAKES, not even what you think is a little.

 

Yes, you can shift on the fly. It doesn't actually shift anything mechanical.

It will slow you down a little, but sometimes it's a little too weak and you might need to use the brakes too. It's like downshifting one gear in a regular car. Sometimes you might need to go down two gears, but there's no option for that in the Prius.

 

THIS.

BUT the resulting transition can be rather abrupt and startling.

I have found that leaving the cruise control ON accomplishes nearly the same thing......but it's better if you drop down to 5 MPH below the posted limit at the top of the hill because you will still gain a little speed going down a long, steep grade......B or not.
A little brake is often needed.

 

That's exactly what it's there for.

And Sam's recommendation of cruise control is excellent when you're on the road. Set the speed you want and the car will maintain it using the most efficient means possible. B mode isn't required for this. The car will regenerate if it needs to do so to keep the speed down. It's a wonder to behold.