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4cyltacomaguy

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Hi, I'm new to this world and considering a purchase. I have a question about the 2021 Toyota RAV4 Prime PHEV - How does the vehicle perform on a long drive when the battery is depleted? Is the performance notably more sluggish? I read a review about the Subaru Crosstrek PHEV and it said that once the battery is depleted the vehicle performance is diminished most notably with more difficulty in climbing hills. TIA
 
IMO, its the opposite way around, in economy mode its kind of pokey when I need to pass someone, I usually switch it to Sport mode, once it goes to hybrid mode its decidedly quick but if you watch the fuel economy gauge, there is no such thing as free lunch, those fast passes slurp the fuel.
 
I think this used to be an issue on some hybrids but like my last PHEV which was 300bhp across the 3 motors it reserves battery for hard acceleration and when not accelerating it works the ICE slightly harder to generate charge for the battery so it constantly ensures the reserve of the battery is topped up. You can still deplete this reserve however but not in any normal driving conditions. Going up steep grade for a very long time at high speed possibly towing might do it. Not sure anyone has managed this though.

Whereas on the Mitsubishi Outlander SUV PHEV a few years back once you ran out of battery a turtle (technically a tortoise) symbol would appear on the dash and things went altogether slow. Neighbour had one. He was constantly moaning about it.

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Whereas on the Mitsubishi Outlander SUV PHEV a few years back once you ran out of battery a turtle (technically a tortoise) symbol would appear on the dash and things went altogether slow. Neighbour had one. He was constantly moaning about it.
That was not my experience with a 2018 Outlander PHEV. I ran it out of battery all the time and never once saw the turtle.
 
That was not my experience with a 2018 Outlander PHEV. I ran it out of battery all the time and never once saw the turtle.
This was a little while before. 2014 or 15. Early model. Long 75mph highway drives on business sapped any reserve of there was one. According to my Tesla owning neighbour anyway.

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That was not my experience with a 2018 Outlander PHEV. I ran it out of battery all the time and never once saw the turtle.
Here's some discussion...


I suspect the issue was that there was a reserve but because the battery was so small (hence very small reserve) you could deplete that reserve on a long high speed drive or whilst towing faster than it could be topped up.

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When Prime runs out of EV range it does not flash a turtle icon. It flashes a rocket icon.
Be interesting to see how the EV range can be completely depleted. But I suspect that Toyota has selected an upper EV speed limit based upon maintaining balance between generator input to the battery (to maintain the reserve) and energy flow out the battery for sea level, straight and level driving (at max 84mph). It is how I would engineer it.

If the above is true then I suspect a long drive up a not too steep grade at just below 84mph might actually deplete the reserve, especially if towing. Wonder what symbol you might get on the dash? Turtle, slug, or snail? Still, if the ICE is kicking out 180hp that's most likely pretty good enough for such rare circumstances.

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Be interesting to see how the EV range can be completely depleted. But I suspect that Toyota has selected an upper EV speed limit based upon maintaining balance between generator input to the battery (to maintain the reserve) and energy flow out the battery for sea level, straight and level driving (at max 84mph). It is how I would engineer it.

If the above is true then I suspect a long drive up a not too steep grade at just below 84mph might actually deplete the reserve, especially if towing. Wonder what symbol you might get on the dash? Turtle, slug, or snail? Still, if the ICE is kicking out 180hp that's most likely pretty good enough for such rare circumstances.

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The System won’t let that happen.
 
The System won’t let that happen.
Wondering how will it not let that happen? Laws of physics are the laws of physics? What would it do when you're at high constant speed going up an inclined road possibly towing a trailer? A lot of power required. Certainly more than the 180hp ICE kicks out which means it's using the emotors and hence battery for any power required above the 180.

If it couldn't happen (because the system doesn't somehow allow it) why would Toyota put the blue lower region marker on the SOC gauge. No need. They'd have just run the gauge to cover the non reserved part of the battery. No need to let the user know about the reserve as that would be superfluous information and clutter.

I suspect what could happen is the overall power available for traction is reduced to allow for battery reserve top up?

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Wondering how will it not let that happen? Laws of physics are the laws of physics? What would it do when you're at high constant speed going up an inclined road possibly towing a trailer? A lot of power required. Certainly more than the 180hp ICE kicks out which means it's using the emotors and hence battery for any power required above the 180.

If it couldn't happen (because the system doesn't somehow allow it) why would Toyota put the blue lower region marker on the SOC gauge. No need. They'd have just run the gauge to cover the non reserved part of the battery. No need to let the user know about the reserve as that would be superfluous information and clutter.

I suspect what could happen is the overall power available for traction is reduced to allow for battery reserve top up?

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So you’re asking if the engine or transmission blows up before it stops charging the hybrid battery. I think you need to ask Toyota that question. Or hook up to a large tree and let us know the results 😎

I’m thinking it will choose the battery as it will almost double your HP. Where as if it stops charging the battery the HP goes down significantly.
 
So you’re asking if the engine or transmission blows up before it stops charging the hybrid battery. I think you need to ask Toyota that question. Or hook up to a large tree and let us know the results [emoji41]

I’m thinking it will choose the battery as it will almost double your HP. Where as if it stops charging the battery the HP goes down significantly.
Ha. I'll pass on the tree pulling. Although we did pull a tree stump out with my friend's land rover once. It had no problem.

I think my point is that some driving situations (admittedly rare) will require more power than the ICE (c.180hp) can deliver. In which case it uses the battery to supplement. If those conditions are sustained then the battery including its reserve will be depleted. At which point, no I don't expect the car to blow up, I just expect it to be limited now to 180hp from the ICE and therefore causing you to slow down a lot (only 60% power of max is available at this point).

A way to test this would simply be at a high speed going up an incline and check the rate of battery depletion. Question is how steep and how fast for how long before we reach the cross over point where more energy is coming out than going in the battery. I expect that we may need to add a small 500lb trailer and a reasonable grade and drive for tens of minutes before there is an issue. Nothing for free in physics.

My way of saying it is entirely possible (no way of avoiding it) but the conditions in which it occurs should be very very rare for us. It used to happen on early PHEVs. A bigger battery on the Prime simply means that you have to be in a much worse situation and for much longer to see the same problem.

It will all be solved when we get a compact fusion reactor in our cars.

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