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RAV4 Prime power adequate for sustained uphill climbing

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Chris B.

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Discussion starter · #1 ·
I am considering buying a 2023 RAV4 Prime but am concerned about power for passing during long uphill drives. We frequently drive from the San Francisco Bay Area to Lake Tahoe in CA. The steepest part of this drive is from Auburn to the Donner Summit, an elevation gain of 5900 feet that takes about an hour at 65-70mph. There are only 2 lanes, and every few minutes we encounter and need to pass a slow-moving semi tractor-trailer in the RH lane.
Twenty years ago, I hated the engine noise and lack of passing power when making this climb in our 160 HP Honda CRV. Will the RAV4 Prime sustain those speeds, AND have power to spare when I need to pass semi tractor trailers?
 
#2 ·
In short: yes.

Now, it may sound like the engine is revving a lot harder than it needs to be, but you will not be lacking for any power. The day I got my RAV4 Prime, I began a 700mi+ drive home that included some moderately-mountainous roads and interstates. It had no issues whatsoever.

And before someone suggests this: no, the battery does not need to be charged, and no, you definitely do not need to drive in Charge Mode before the climb. Set it, forget it, and enjoy the car.
 
#4 ·
I remember this was an issue with the BMW i3 Rex - on a sustained climb the engine output didn't generate enough electricity to stay at highway speeds, so it started to at 50mph when the battery was flat. Happened to me once.

But that's a 950cc scooter engine working in series with an electric motor.

The rav4 has a 2.5l engine and a nifty gearbox that seamlessly switches between series/parallel modes, so it won't suffer from the same issue.
 
#5 ·
Same concern here but we have the hybrid with its much smaller battery. We will be driving through Tahoe in August as part of a long road trip to Utah. Our 4.3 Rav v6 had no problems maintaining 70+ MPH going uphill and we anticipate that the gas engine in the 4.5 hybrid/prime can do the same. The problem is how much reserve battery capacity and gas engine horsepower is there for acceleration bursts when needed? I think it's a much better bet the prime wil be able to provide the full 302 HP during repeated passing maneuvers. I have a suspicion the hybrid won't be able to do the same as each burst will drain the battery that then has to quickly recharge from excess capacity of the already straining gas motor.

Probably the strategy with the prime may be to set it so the battery starts at 80% prior to climbing the mountain passes when you anticipate having to do a lot of passing. There's no such setting in the hybrid unfortunately.
 
#7 · (Edited)
When I used to live in California and people made that climb over the peak summer, you would always see cars pulled over to the side of the road due to engine temperature issues (overheating). A lot of them would try to put water in their radiator as a temporary measure. The RAV4 Prime has plenty of power to go up the hills, overtake on the hills, and even pull a trailer up those hills.. just do the basics, make sure your radiator coolant is topped off, you don't have obstructions near your radiator cooling fans, and you keep an eye out your engine temperature (there is a sensor that will warning you with a dash light if your engine starts to overheat beyond the normal range or you can get a tool like the ScanGauge that connects to your OBD-II port).

~ im2bz2p345 :)
 
#9 ·
RavForTwo said:
Same concern here but we have the hybrid with its much smaller battery. We will be driving through Tahoe in August as part of a long road trip to Utah. Our 4.3 Rav v6 had no problems maintaining 70+ MPH going uphill and we anticipate that the gas engine in the 4.5 hybrid/prime can do the same. The problem is how much reserve battery capacity and gas engine horsepower is there for acceleration bursts when needed? I think it's a much better bet the prime wil be able to provide the full 302 HP during repeated passing maneuvers. I have a suspicion the hybrid won't be able to do the same as each burst will drain the battery that then has to quickly recharge from excess capacity of the already straining gas motor.

Probably the strategy with the prime may be to set it so the battery starts at 80% prior to climbing the mountain passes when you anticipate having to do a lot of passing. There's no such setting in the hybrid unfortunately.
Click to expand...
The clever engineers at Toyota are ahead of you. The "Hybrid Synergy" setup with M1 and M2 and the funky planetary variable gear ratio allows for some amazing tricks. The one that you folks embarking on a sustained climb will like is this: Its NOT just regenerative braking that can charge the battery. When the battery capacity gets so and so low, the car knows that could potentially need the battery for acceleration, so it starts to use M1 or M2 (that part escapes me right now) to generate electricity to charge the battery. No braking involved. This will result in the little 2.5l 4 banger running pretty much constantly, BUT it will have a reserve charge in the battery to handle periods of additional acceleration.

Now, could you overdo it? I suspect at some point, especially if you were to try to maintain say 85 mph going up a mountain, or you were towing at high speed up same mountain, well then at some point the 4 cyl engine has no reserve left to charge the battery. Then the battery could start to get less and less charge. HOWEVER, I suspect Toyota has made this impossible. Why? Because the traction battery MUST keep a certain amount of charge always, since it functions as the starter as well, the engineers would probably throttle your speed before they let you deplete the battery. This is an educated guess on my part, but I bet its true.
 
Discussion starter · #10 ·
cdherman said:
The clever engineers at Toyota are ahead of you. The "Hybrid Synergy" setup with M1 and M2 and the funky planetary variable gear ratio allows for some amazing tricks. The one that you folks embarking on a sustained climb will like is this: Its NOT just regenerative braking that can charge the battery. When the battery capacity gets so and so low, the car knows that could potentially need the battery for acceleration, so it starts to use M1 or M2 (that part escapes me right now) to generate electricity to charge the battery. No braking involved. This will result in the little 2.5l 4 banger running pretty much constantly, BUT it will have a reserve charge in the battery to handle periods of additional acceleration.

Now, could you overdo it? I suspect at some point, especially if you were to try to maintain say 85 mph going up a mountain, or you were towing at high speed up same mountain, well then at some point the 4 cyl engine has no reserve left to charge the battery. Then the battery could start to get less and less charge. HOWEVER, I suspect Toyota has made this impossible. Why? Because the traction battery MUST keep a certain amount of charge always, since it functions as the starter as well, the engineers would probably throttle your speed before they let you deplete the battery. This is an educated guess on my part, but I bet its true.
Click to expand...
Thanks for the input, and for the educated guess--it does make sense. Now I'm grappling with the $10k dealer markup. I wonder when production will have ramped up to reduce that. I'll check for threads on that topic but your view on that is welcome here.
 
Discussion starter · #11 ·
Im2bz2p345 said:
When I used to live in California and people made that climb over the peak summer, you would always see cars pulled over to the side of the road due to engine temperature issues (overheating). A lot of them would try to put water in their radiator as a temporary measure. The RAV4 Prime has plenty of power to go up the hills, overtake on the hills, and even pull a trailer up those hills.. just do the basics, make sure your radiator coolant is topped off, you don't have obstructions near your radiator cooling fans, and you keep an eye out your engine temperature (there is a sensor that will warning you with a dash light if your engine starts to over heat beyond the normal range or you can get a tool like the ScanGauge that connects to your OBD-II port).

~ im2bz2p345 :)
Click to expand...
Good idea to check radiator fluid and fans unobstructed, especially for the summer drives to Tahoe.
 
#12 ·
Chris B. said:
Good idea to check radiator fluid and fans unobstructed, especially for the summer drives to Tahoe.
Click to expand...
And make sure the fans are plugged in. There have been instances where recalls required the fans to be unplugged during the process and the service people have forgotten to plug them back in. In particular, the VSC recall.
 
#13 ·
I tried this in my Prius years ago. Triple digits going up a mountain. I got it down to one or two bars (can’t remember). Never could tell that it ran out of power. I don’t think there’s a road steep enough and high enough for this to be a real problem. There is plenty of headroom with ICE alone. (BTW im older and wiser now).
 
#14 ·
The engine sounds very, very stressed going uphill for extended periods, it’s one of my biggest annoyances with the Prime, but with the horses onboard you should have no issues teleporting past anyone in your way.
 
#15 ·
cdherman said:
The clever engineers at Toyota are ahead of you. The "Hybrid Synergy" setup with M1 and M2 and the funky planetary variable gear ratio allows for some amazing tricks. The one that you folks embarking on a sustained climb will like is this: Its NOT just regenerative braking that can charge the battery. When the battery capacity gets so and so low, the car knows that could potentially need the battery for acceleration, so it starts to use M1 or M2 (that part escapes me right now) to generate electricity to charge the battery. No braking involved. This will result in the little 2.5l 4 banger running pretty much constantly, BUT it will have a reserve charge in the battery to handle periods of additional acceleration.

Now, could you overdo it? I suspect at some point, especially if you were to try to maintain say 85 mph going up a mountain, or you were towing at high speed up same mountain, well then at some point the 4 cyl engine has no reserve left to charge the battery. Then the battery could start to get less and less charge. HOWEVER, I suspect Toyota has made this impossible. Why? Because the traction battery MUST keep a certain amount of charge always, since it functions as the starter as well, the engineers would probably throttle your speed before they let you deplete the battery. This is an educated guess on my part, but I bet its true.
Click to expand...
Agree with you, and is why I wrote that my suspicion is that the hybrid will be hard pressed to recharge its quickly depleted and small battery in between bursts of speed with an already straining gas engine. The 176 HP the ICE makes should be sufficient to have some excess capacity because that level of power should be enough for high speed, steady state mountain pass climbing, but the engine will not be very melodious about it. We will know on our road trip in August.
 
#16 ·
RavForTwo said:
Same concern here but we have the hybrid with its much smaller battery. We will be driving through Tahoe in August as part of a long road trip to Utah. Our 4.3 Rav v6 had no problems maintaining 70+ MPH going uphill and we anticipate that the gas engine in the 4.5 hybrid/prime can do the same. The problem is how much reserve battery capacity and gas engine horsepower is there for acceleration bursts when needed? I think it's a much better bet the prime wil be able to provide the full 302 HP during repeated passing maneuvers. I have a suspicion the hybrid won't be able to do the same as each burst will drain the battery that then has to quickly recharge from excess capacity of the already straining gas motor.

Probably the strategy with the prime may be to set it so the battery starts at 80% prior to climbing the mountain passes when you anticipate having to do a lot of passing. There's no such setting in the hybrid unfortunately.
Click to expand...
I've never seen any info that suggests that the hybrid uses the battery for extra power. ???? Anyone?
 
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#17 ·
The car can be kind of amusing going up long hills. We have some roads that are mostly 2 lane, but there is a "slow" lane for some of the long hills. I typically do the speed limit +10mph, but there are still folks who end up backed up behind me. So while they could pass me on the uphills, they often cannot, because I can go uphill without slowing down, while they are falling behind. Anyway, no lack of power
 
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