Oh Wow

Star Trek noise? Does it ask you to beam something up?

 

20% improvement, amazing!

 

If it's the same as the PiP, I always thought it sounded like the first War of the Worlds (movie) machine movement sound sped up...

Awesome particularly since it's 150kg heavier.


Unsupervised!

 

Very nice. Congrats

 

Which Prius has better acceleration, Prime or regular?

 

I just did a test drive on the first Prime in the Denver area. "Wow" is right.

The Prime is 4-5db quieter at 55 than my 2004 is (68-69db versus 73db on a non-calibrated device). At 65, it's still 3db quieter than my 2004 at 55 (70db versus 73db). Same road, same road surface.

The Prime (Advanced) I drove has Toyo Nano Energy tires.

The thing is crazy smooth when starting and stopping the engine. At lower power levels, it's undetectable. At high power levels, it's only detectable by the sound. It feels absolutely seamless. Very impressive.

Plenty of power and responsiveness. No issues at all climbing an on ramp to a 65 zone at less than half throttle. Very nice.

 

I should have mentioned that these numbers were for Hv mode. I tried to measure a difference between Hv and Ev at 65mph and it was barely detectable - maybe 1db or so. That's because the engine is virtually silent at cruise power. At acceleration power, the difference is larger - perhaps 3db or so depending on throttle level.

One other thing. When I started the test drive, Ev mode was depleted. So I tossed it into charge mode right away so I'd have a little Ev to play with along the route. Now, on a short test drive charge mode doesn't give you much, so I only had one or two pixels above the line on the battery display when I put it into Ev mode. I then wanted to see the acceleration in Ev mode so I gradually pushed the accelerator down toward the floor. It took off well but as I got to about 75% throttle position, it started the engine. We knew it would do this in Ev mode at low levels of charge, but what took me by surprise is that I couldn't detect it other than by the sound. Even in hard acceleration - at an accelerating rate - starting the engine from off for assist just felt like Ev mode. It was completely smooth and the instant I let off the accelerator the engine stopped. It was only running for perhaps two seconds.

 

no question the gen IV cabin is quieter, but without running the same tires, the measurements can be skewed.

 

That was Toyo NanoEnergy on the Prime versus Ecopia 422 Plus on the 2004.

 

exactly. the tires could have been the whole difference, or some, or none. or even made the 2004 quieter than it would be with nano's.

 

Off topic sorry, but can we estimate the weight of the prime traction battery? We know the weight difference between the two cars but there are lots of other factors in there so not a good guide. Thx.

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265 pounds.

2017 Prius Prime (Plug-in Hybrid) Full Product Information & Technical Docs (PDF) | PriusChat

 

Thanks.

So per kwh of capacity that's about 30.1 pounds or 13.65 kilos.

Or per mile of range that's around 10.6 pounds or 4.8 kg.

Does anyone know what the predicted rate of energy density improvement is, in terms of weight, over the next few years?

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That's 73Wh/kg. By modern standards, that's horrible. The best is about 3-4 times that amount.

I suspect most of the weight is packaging, protection from impacts, thermal control, and monitoring, rather than the batteries themselves. They should be in the 200Wh/kg range, give or take a little.

That's the problem with improvement. If the batteries become zero mass, this battery would only decrease in weight by a third or so.

They're going to have to do a better job of packaging if they want to make the batteries lighter.

In answer to your question, battery energy has been increasing by something like 7% a year. That is expected to decrease without changes to the fundamental structure of the batteries.

Lithium metal anodes have the potential to make the batteries twice as energy dense. So, you'd get twice the range from the same battery.

Lithium Sulfur has the potential to make the batteries 2-5 times as energy dense. Both are in active development.

 

Thanks! V v interesting!!

So depending on the cost being a acceptable, there is the potential, theoretically at least, for owners to retrofit replacement traction batteries in the Prime in future, to double the range, or possibly if someone is prepared to manufacture a smaller battery package and cooling etc to reduce battery pack size and have a bit more cargo space? From what you say the second option is pretty limited in potential for space saving?

Is the cost reducing too with these developments, or does that mostly depend on economies of scale following increased sale volumes?

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Yeah, retrofit is theoretically possible.

Yes, cost is decreasing too.

 

I drove 15 miles to work but only spent EV 12miles of juice. Maybe the traffics is so bad at Bay Area - bumper to bumper speed.. couldnt wait to get my hov sticker... really bad.


iPhone ?