[Sierra Sam]

Several people have mentioned the use of paddles or shifter to avoid braking. The main benefit would be to extend the life of the brake pads. Does anyone know what parts wear faster when you 'downshift'?

FYI, you don't need to be in S mode to downshift - it works equally well to do so in D mode and use the paddles.

 

[chuckles70]

Does anyone know if the battery management software in the Rav4 Prime, contains code to shut down EV mode automatically and switch to HV mode, if the battery temp rises to some pre-defined maximum safe temperature? If so, what is that temperature?

I don't think anybody knows. I can tell you that I live on top of a tall, steep hill, and when I launch out at anything above a medium SOC the engine kicks in. I don't think it's temp related though. If anything temp is too low, not too high.

Remember that Tesla vehicles precondition batteries for supercharging, and the temps they achieve to soak the charge current would scare you. Higher temp is not inherently bad.

Also note that your observation of 68kw being an incredible amount of energy in a climb, is in the realm of 3.5C discharge rate on our 18kw pack. That is actually a relatively small load for Li chemistry. I have batteries that are rated for 45C in hobby applications. (15x that rate).

 

[eugenepowers001]

I love my 2021 RAV4 Prime, but there are some quirks that bug me ...

• The vibration in the steering column cover molding that drives me crazy because I can't get it to shut up!
• The way the door frames drip big drops of water or globs of snow on my seats when the doors are opened (instead of deflecting it)
• The high passenger seat and low door opening, so that my (medium height) passengers repeatedly bump their heads getting into the vehicle
• The Toyota Cruise Control system (I'm a long-time Honda driver) that requires multiple buttons to be pressed (while keeping eyes on the road...!) and half the time I switch off instead of on! (With Honda, you can leave the cruise control system on, and just set/accelerate/decelerate/resume/clear as needed. You don't have to switch cruise control ON every time you drive.)
• The way the interior knobs and switches are all pitch black in the dark.

I'm sure I have forgotten a few. Anyone else? Maybe Toyota designers will pay attention some day?

A lot of these were fixed in 2023.
The only thing remains is the APP.

 

[eugenepowers001]

OK, so on that first bullet point… At least on my car, if I press my finger against the plastic right before the flappy pedal area on the steering wheel, it stops the buzzing noise. If it’s the same one you’re talking about.

Agreed to the other quirks, with the slight exception that you can get lighted switches pretty cheap online. I did that mod myself first thing. Still wish the overhead buttons were lit, though.

My main issue that you didn’t note, is how many times this car BEEPS at you! When you’re getting in, getting out, opening a door, it’s just endless. I would like some peace and quiet, please 🙏

Get a cable and software to change the beeps.

 

[chuckles70]

Several people have mentioned the use of paddles or shifter to avoid braking. The main benefit would be to extend the life of the brake pads. Does anyone know what parts wear faster when you 'downshift'?

FYI, you don't need to be in S mode to downshift - it works equally well to do so in D mode and use the paddles.

I guess the paddle buttons wear. Seriously- there's no real difference. The brake pedal does the same thing. Use of the brake starts with regen, until you've exhausted that capability and the friction brakes come in.

 

[eugenepowers001]

For a second I thought you were serious! Then I realized you're being sarcastic here. Agree 100% that the Hybrid Synergy Drive is wonderful to begin with, and the S1-S6 controller for the regen braking system is a GREAT feature.

Last week, I drove home from Death Valley National Park, and if you've never been there, the only paved roads (Highway 190, Highway 178, and Daylight Pass Road through Beatty, NV) all involve climbs over mountain passes with 3,600 to 5,000 feet of elevation gain and descent. My route was over Towne Pass on 190. You climb from sea level at Stovepipe Wells to the summit of Towne Pass at 5,000 feet: 16.7 miles at an average grade of 5.7%. Then the descent into Panamint Valley is 9.4 miles at an average grade of 7%, but with several sections that are up to 2 miles long, at 9%. Daylight Pass Road between Beatty and Stovepipe Wells Junction has sections just as steep. Controlling your speed on these crazy-steep descents is so easy in the Rav4 Prime! Plan your route and usage of EV mode so as to arrive at the top of the pass with the traction battery somewhere between 14% and 35% State of Charge, then start the descent in S4 mode at 35 mph (that's about as fast as you want to go on these hills). If the car starts to exceed 35 mph, shift down to S3 or S2. Unless the car is carrying a very heavy load, or you're towing a trailer, S2 and S3 will almost certainly hold your speed around 35 mph, all the while pumping 16 ~20 kilowatts of regen braking energy into the traction battery. This is why you want to plan to arrive at the top of the hill with the traction battery low, so that it can accept a lot of charge. If the hill gets so steep that S2 mode regen can't hold the speed at 35 mph, the computer will spin up the ICE in compression braking mode. This wastes potential energy that could be going into the battery. If this happens, stop the car (if you won't block traffic), so that the ICE will shut down, then start again in EV mode with S2 set. You should easily make it to the bottom of this 9 mile descent having regained up to 30 miles of EV range, and without ever having to use the friction brakes except to stop and reset the ICE to get it out of compression braking mode.

NOTE: DO NOT climb long, steep up-grades like Towne Pass in EV mode; you could overheat the traction battery. The car will let you do this, but if you are running an OBD-II scanner app like Torque Pro or CarScanner, and you are monitoring the traction battery maximum temperature, you will likely see it rise VERY fast, in this real-life example, from 70°F to 118°F in just the first couple of miles. Climbing a 9% grade in EV mode at 35 mph, the MG2 motor will be pulling up to 180 amps out of the battery (that's 63 kilowatts), and while the powertrain controller will let you do this, I can't imagine that it's good to push the battery and inverter this hard for several miles continuously, based on how fast I saw the battery temperature climb in just the first 5 minutes before I switched to HV mode. I don't know what Toyota considers to be the maximum safe battery temperature, and I also don't want to find out the hard way. So be careful climbing steep hills in EV mode if they are more than maybe 1/4 mile long.

I have been in the DV many times but always in the January or end of February because I go to LV afterwards. Does battery heat up in the cold too?

 

[wscan]

Does the a/c heat pump have to be switched on by the driver in the cabin for the battery cooling system to do this, or will the car's computer controls automatically run the heat pump in a/c mode to cool the battery? The only other time I've ever seen the battery get really hot was during a 3-day visit to a friend in Las Vegas last July during a heat wave, when the daytime high temp in the city hit 116°F every afternoon for a full week. My battery temp was 115°F with the car just sitting in the parking lot at the apartment complex. When we drove it to dinner, it did gradually cool down to about 100°F after several miles of driving. It kind of worries me that the Rav4 Prime has no gauges on the instrument cluster for temperature of any of the components. CarScanner has PID's available for several temperature sensors at various places in the powertrain. I keep 5 of them active on the display: ICE Coolant Temp, ICE Oil Temp, Traction Battery Max Temp, and both the Primary and MGR Inveter Coolant Temps. I'd like to display the stator temps for MG1, MG2, and MGR, but CarScanner doesn't yet have a dedicated Vehicle Profile for the Rav4 Prime, and the equivalent stator temp PID's for the 2019 Prius Prime don't work in the 2023 Rav4 Prime. On my trip out of Death Valley last week, climbing Towne Pass, the ICE Coolant Temp maxxed out at 204°F (average is 198°F cruising on the freeway at 55 mph). ICE Oil Temp maxxed out at 220°F, and the traction battery and inverter temps only increased by about 5° since I used HV mode for the ascent. On the descent, I started with 40% SOC at the top of the pass. By the bottom, 9 miles later, the SOC had increased to 74%. Surprisingly, the battery temp hardly rose at all, despite very aggressive use of regen braking: the average power being pumped into the battery was 18 kW, 3 times higher than the 6 kW maximum you can get from an L2 EVSE. Battery temp started at 70°F at the top of the hill, and rose to 76° at the bottom of the hill. Apparently, charging the battery via continuous full-power regen braking, generates a lot less internal heating than does rapid discharging when climbing a steep hill in EV mode.

Does anyone know if the battery management software in the Rav4 Prime, contains code to shut down EV mode automatically and switch to HV mode, if the battery temp rises to some pre-defined maximum safe temperature? If so, what is that temperature?

The car will automatically run the HVAC system to cool the battery when necessary, regardless of the settings for the cabin.

For your question about maximum battery temp switch to HV mode, I do not have a definitive answer, although I would expect Toyota has some protection built in to the system.

On your comment about battery temperature, the regen power of 18 kW is substantially less than a discharge rate of 180 of so amps, which is roughly 68 kW. This is over 3.5 times the recharge rate, so I would expect roughly 3.5 times the heat generated, although I do not know if discharge heat is symmetric with charge heat.

 

[Laura-Ann]

I have been in the DV many times but always in the January or end of February because I go to LV afterwards. Does battery heat up in the cold too?

Here are the specific environmental factors during my trip:
On Sunday Nov. 26, I climbed Towne Pass on CA-190, eastbound from Panamint Valley Road, at about 2:00pm, the ambient air temp was about 65°F. I had the cruise control set at 35 mph. The traction battery had 80# SOC at the start of the climb. For the first three miles up the alluvial fan, the grade was about 3%, typical of fans in the area, and the battery temperature was rising slowly enough that I wasn't worried. It was about 70°F at the start, and 78°F after those first three miles. But then the grade increased to about 7%, and the power demand from the battery shot up to nearly 60 kilowatts, and the battery temperature started rising fast, hitting 118°F after only 6 or 7 minutes. At that point, I was still not even halfway to the summit of the pass, and I switched to HV mode rather than risk damaging the battery. This is why I really take issue with Toyota not putting a temperature gauge on the instrument panel for critical component temperatures. After I reached the summit and started back down the east slope toward Stovepipe Wells, the battery was charging up again in regen braking mode, and the temperature began to drop, reaching 95°F when I stopped at Stovepipe Wells to top off the gas tank.

A week later, I left to go home, reversing the route, except that I did not try to climb Towne Pass in EV mode. There was no significant increase in battery temperature while climbing in HV mode. At the summit, I switched to EV mode for the descent, and by the bottom of the hill, the battery temperature had risen only about 5% from regen brake charging.

So the takeaway from my real-life experience, is that rapid battery discharge during long, steep hill climbs in EV mode, produces a lot more internal heat in these Rav4 Prime batteries, than does even very aggressive (near maximum) regen braking on a 9% downgrade. To answer your specific question, YES, even in relatively cool California winter weather (with temperature in the low to mid 60's), climbing steep hills in EV mode can heat up the battery alarmingly fast, far more so than charging it either by regen braking, or with a 6 kilowatt Level 2 EVSE.

I've been trying to find specs on the Internet for maximum safe operating temperature of the LG branded gel-electrolyte lithium-ion battery cels used in the Rav4 Prime, but haven't found any specific numbers. Some websites suggest that these batteries best charging performance is between 75°F and 95°F, but that's not the same as actual operating temperature when discharging. Maybe someone here who is a Certified Toyota technician knows the answer?

 

[Laura-Ann]

The car will automatically run the HVAC system to cool the battery when necessary, regardless of the settings for the cabin.

For your question about maximum battery temp switch to HV mode, I do not have a definitive answer, although I would expect Toyota has some protection built in to the system.

On your comment about battery temperature, the regen power of 18 kW is substantially less than a discharge rate of 180 of so amps, which is roughly 68 kW. This is over 3.5 times the recharge rate, so I would expect roughly 3.5 times the heat generated, although I do not know if discharge heat is symmetric with charge heat.

Thanks for your reply here. It's good to know that the BMS will run the heat pump automatically to cool the battery. When I was climbing that long steep hill, it was kind of a shock to me, how fast the battery temperature rose. It was a learning experience for sure, and I definitely won't do another hill climb in EV mode. By downshifting to S2, and squeezing the brake pedal a little to force an increase in regen braking, I've observed the regen braking power hit 40 kilowatts for brief periods, up to maybe 6 or 7 seconds, but the car seems unwilling to allow that for any extended period; after 10 seconds or so, if the car is still moving at more than about 20 mph, the ICE aotomatically spins up in compression braking mode and the friction brakes might engage even if you don't want that to happen. Trying to force a sustained high rate of charge (more than about 15 kilowatts) by deliberately manipulating the regen braking system, seems to trigger the BMS to simply not allow you to do this, presumably to protect the battery from damage or overheating.

 

[chuckles70]

It kind of worries me that the Rav4 Prime has no gauges on the instrument cluster for temperature of any of the components.

Toyota's design ethos in the Hybrids (from which the Prime is derived) is much closer to an appliance than a C130 cockpit. You'll find as many temp gauges on your toaster as you will on the Prime. That is intentional. They built this platform so the consumer doesn't have to worry. I have personally towed a 2300lb load up a sustained 20+% grade, and on a normal day my climb home draws > 100kw. Between 315 and 340 A @ 355v bus voltage.

Like you, I get a kick out of all of the data you can stream out of the OBD. It's interesting. But I have to trust that the engineers have done their job, and being on this forum for over 2 years now and as passionate as anybody about the platform, no one to my knowledge has yet cooked a battery or an inverter. I have to think we'd heard about that by now. There are plenty of hot, steep places these cars have been (as well as extreme cold), and the platform seems to be holding up. It's just not something I'd worry about.

 

[FKHeath]

FYI, you don't need to be in S mode to downshift - it works equally well to do so in D mode and use the paddles.

Not all RAV4 come with paddles. Mine does not. Perhaps the Prime, but I have an XLE Premium hybrid.

The RAV4 will automatically downshift to provide engine braking when the computer thinks it is needed to keep speed in check. For example, there is a very long (5+ miles) steep down hill, high speed (55 MPH speed limit) near my home. Every time I go down that hill, the RAV4 first starts with regeneration. Then if regeneration does not keep the speed in check, the ICE will come on and the transmission "shifts" to a lower gear. I have see ICE RPMs as high as 4000 going down that hill.

 

[Laura-Ann]

Toyota's design ethos in the Hybrids (from which the Prime is derived) is much closer to an appliance than a C130 cockpit. You'll find as many temp gauges on your toaster as you will on the Prime. That is intentional. They built this platform so the consumer doesn't have to worry. I have personally towed a 2300lb load up a sustained 20+% grade, and on a normal day my climb home draws > 100kw. Between 315 and 340 A @ 355v bus voltage.

Like you, I get a kick out of all of the data you can stream out of the OBD. It's interesting. But I have to trust that the engineers have done their job, and being on this forum for over 2 years now and as passionate as anybody about the platform, no one to my knowledge has yet cooked a battery or an inverter. I have to think we'd heard about that by now. There are plenty of hot, steep places these cars have been (as well as extreme cold), and the platform seems to be holding up. It's just not something I'd worry about.

Thanks for this reply! Can I ask what you are towing with your R4P? I am looking at an Aliner pop-up camping trailer. I know someone in Las Vegas who is towing an Aliner with a Rav4 Prime and was thinking about getting one myself, but have been worried about overstressing the Prime's powertrain, especially climbing long freeway upgrades.

 

[chuckles70]

Thanks for this reply! Can I ask what you are towing with your R4P? I am looking at an Aliner pop-up camping trailer. I know someone in Las Vegas who is towing an Aliner with a Rav4 Prime and was thinking about getting one myself, but have been worried about overstressing the Prime's powertrain, especially climbing long freeway upgrades.

It’s a StarCraft tent camper similar to an Aliner. It’s probably @lutey that you mentioned? He tows an Aliner with his Prime and has a YouTube channel that talks all about it.

Note this drivetrain is derived from the Sienna / Highlander (sans battery), both of which are rated 3500 LB.

Now in full disclosure my jeep rubicon is a better match for the trailer, but it gets less than half the mpg (~12 vs ~26 or so). My preference is more about platform stability and additional cargo than frying the drivetrain.

 

[Laura-Ann]

It’s a StarCraft tent camper similar to an Aliner. It’s probably @lutey that you mentioned? He tows an Aliner with his Prime and has a YouTube channel that talks all about it.

Note this drivetrain is derived from the Sienna / Highlander (sans battery), both of which are rated 3500 LB.

Now in full disclosure my jeep rubicon is a better match for the trailer, but it gets less than half the mpg (~12 vs ~26 or so). My preference is more about platform stability and additional cargo than frying the drivetrain.

Yes, it was in fact Darrel Lutey I was referring too. I've been following both his comments here and his YouTube videos regarding the R4P and the Aliner camper for several months, trying to decide if I want to get an Aliner myself. If you've ever camped in Death Valley National Park, you maybe know about the crazy wind storms they get there a few times a year, where it can blow 50 mph or more for maybe 36 hours strait. Not ideal conditions for tent camping, so I am looking into some kind of hard-sided camper trailer that can stand up to a Death Valley windstorm. D.V. is my favorite place to go camping in the winter months, so I am there at least once almost every winter, some years twice, November and February.

Like your Jeep, I also have a secondary vehicle that's much more capable for trailer towing than my Rav4 Prime: a 1998 Dodge Ram 2500 pickup truck with a Cummins diesel and 5-speed manual transmission. I've used it to tow an 8,000 pound sailboat + trailer on 2,000 mile round trips to Bellingham, WA a couple of times. It does this job wonderfully, as you would expect, but this particular truck isn't a 4WD one - not ideal for driving the backcountry dirt roads in Death Valley, and of course it's fuel economy sucks; about 14 mpg, and this in an era when diesel fuel costs $1.00/gallon MORE than the regular gas that mu R4P uses. So I rarely use the truck anymore except when I need to haul plywood or lumber home from Lowes, or I need to tow a trailer.

Towing the Aliner cuts the fuel economy for Darrel's R4P from 40 mpg down to about 25 mpg. Not ideal, but still not as bad as my Dodge diesel pickup. And the R4P would give me an AWD vehicle with which to explore the backcountry roads, at least the Class 1 to Class 3 ones. I'm not crazy enough to take a Rav4 on Lippincott Mine Road or through Steele Pass and Dedeckera Canyon Road; that's where you really need that Jeep Rubicon!

 

[fay.bosman]

A lot of these were fixed in 2023.
The only thing remains is the APP.

Nice!

 

[ptom]

On my '21 Prime anyway, the most annoying thing so far is the over head light switch, wherever it is. It was quicker this morning to get my cell phone flashlite out than try and find the switch. Bad design, no doubt done when in a well lighted room! I'd love to put one of the engineers in the car and have them quickly find it while driving down a twisty mountain road with spots of black ice, in the dark, while scanning for deer. Note to self: look at the switch's location in the daytime, something I keep forgetting to do.

Speaking of towing trailers: I was looking at this jet ski all aluminum trailer yesterday, only 380 pounds! Take off the not needed stuff and with a few mods it'd be the ultimate super light weight trailer for carrying a few sheets of plywood (54" between the wheels), or some longer than 10' lengths of lumber, red flagged if need be. 10'ers fit in side of course, like in my Prius. Like others here, I have a big fire breathing 4x4 1 ton truck for when I REALLY need it, but no way am I am driving it into town for minor loads.

 

[chuckles70]

On my '21 Prime anyway, the most annoying thing so far is the over head light switch, wherever it is. It was quicker this morning to get my cell phone flashlite out than try and find the switch. Bad design, no doubt done when in a well lighted room! I'd love to put one of the engineers in the car and have them quickly find it while driving down a twisty mountain road with spots of black ice, in the dark, while scanning for deer. Note to self: look at the switch's location in the daytime, something I keep forgetting to do.

Speaking of towing trailers: I was looking at this jet ski all aluminum trailer yesterday, only 380 pounds! Take off the not needed stuff and with a few mods it'd be the ultimate super light weight trailer for carrying a few sheets of plywood (54" between the wheels), or some longer than 10' lengths of lumber, red flagged if need be. 10'ers fit in side of course, like in my Prius. Like others here, I have a big fire breathing 4x4 1 ton truck for when I REALLY need it, but no way am I am driving it into town for minor loads. View attachment 201533

I've had some variant of one of these for 30 years now. Cheaper than a truck, easier to load, you don't have to worry about tearing them up, convenient to loan to friends, etc. etc. In the rare event that I need to move something heavier, that's when UHaul or delivery comes into play. On the newer models the ramp unbolts or will fold flat.

5X8G - Carry-On Trailer

www.carry-ontrailer.com

 

[ptom]

My homebuilt one is similar, small enough to move around by hand, nothing there that doesn't need to be there, but still made of carbon steel. The all aluminum ones just appeal to the weight weenie in me!

 

[Laura-Ann]

I agree, it's nice to come to this site and learn from other Prime owners experiences with tips & tricks and whatever else about owning this Rav4, I especially like it when people share all the Positive stuff they love about it like how you feel so good driving it, effortless cruising, no hesitation coming off the line, all the safety features, ETC... I could go on forever, I just love ALL the nice stuff that over powers the little stuff that could get in the way of enjoying driving this wonderful RAV4 PRIME.

There's no such thing as a "perfect" car. There will always be some little quirk in a car that you will wish wasn't there. The beauty of the Rav4 Hybrid and Prime is that these cars are SO well made, and so versatile, that's it's easy to ignore a couple of minor annoyances and just enjoy the car for what is has to offer: excellent fuel economy for such a large and heavy box-on-wheels, a wonderfully smooth and quiet driving experience that lets you have a conversation with your passenger(s) without having to shout. A reasonably informative display of driving data on the instrument panel, reasonably good seats (wish they were a bit larger and more comfortable). HUGE interior volume and carrying capacity, for a vehicle that's actually only about the same length and width as a Corolla.
It's extremely well thought out, too. Adding a trailer hitch receiver myself, in my own garage, was far less difficult than it might have been: I didn't have to remove or cut into the bumper or drop the muffler to do it. Same with the roof cross bars: they were very easy to add myself.

The Rav4 Prime: It's such a pleasure to drive this car, both in EV and HV modes. It will creep along at 2 mph in a traffic jam, or scoot along at 75 on the freeway, with equal aplomb. Acceleration away from a stop can be as gentle or as aggressive as you want it to be, and the car handles it either way with no sense of discomfort. I've never used even 1/2 of the total 302 horsepower capability of the power train, either to get away from a stop light, or to climb a steep hill. Climbing long 6% upgrades on the freeway, the car has enough power to do this without needing to rev the engine past about 3200 rpm, so it's never obtrusively loud; my 2019 Prius Prime did have to rev to 4200 rpm to climb 6% hills on the freeway, and that was noticeably quite a bit louder than the engine in my Rav4 Prime.

 

[Prime Grip]

There's no such thing as a "perfect" car. There will always be some little quirk in a car that you will wish wasn't there. The beauty of the Rav4 Hybrid and Prime is that these cars are SO well made, and so versatile, that's it's easy to ignore a couple of minor annoyances and just enjoy the car for what is has to offer: excellent fuel economy for such a large and heavy box-on-wheels, a wonderfully smooth and quiet driving experience that lets you have a conversation with your passenger(s) without having to shout. A reasonably informative display of driving data on the instrument panel, reasonably good seats (wish they were a bit larger and more comfortable). HUGE interior volume and carrying capacity, for a vehicle that's actually only about the same length and width as a Corolla.
It's extremely well thought out, too. Adding a trailer hitch receiver myself, in my own garage, was far less difficult than it might have been: I didn't have to remove or cut into the bumper or drop the muffler to do it. Same with the roof cross bars: they were very easy to add myself.

The Rav4 Prime: It's such a pleasure to drive this car, both in EV and HV modes. It will creep along at 2 mph in a traffic jam, or scoot along at 75 on the freeway, with equal aplomb. Acceleration away from a stop can be as gentle or as aggressive as you want it to be, and the car handles it either way with no sense of discomfort. I've never used even 1/2 of the total 302 horsepower capability of the power train, either to get away from a stop light, or to climb a steep hill. Climbing long 6% upgrades on the freeway, the car has enough power to do this without needing to rev the engine past about 3200 rpm, so it's never obtrusively loud; my 2019 Prius Prime did have to rev to 4200 rpm to climb 6% hills on the freeway, and that was noticeably quite a bit louder than the engine in my Rav4 Prime.

I agree, I had a 2017 & 2021 Prius Prime, which were great cars and had great gas mileage but didn't have the get up and go. Traded the 21 PP for this WONDERFUL piece of machinery.
This RAV4 PRIME XSE is what i was MISSING from the Prius Prime. What an UPGRADE.
If any body has any complaints about this POWER PRIME, they should give it back and let some else enjoy it