tesla vs clarity - what are technological differences in battery?
- Thread starter JKroll
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Sandroad
Well-Known Member
There is, of course, much more to acceleration capability than battery differences. Motor HP, motor torque, wire size, electrical control system, power:weight ratio, number of driven wheel(s), tires, differential ratio(s), battery capacity, etc. all play a role. Differences in the technology/construction of the battery may be important too, but only as a part of the overall power delivery system.
Which Clarity? The Tesla Model X battery starts at 75 kWh. The Clarity PHEV has 17 kWh. Battery discharge rates are measured in C (capacity), where they might be listed as 5C, meaning it can discharge at a rate of 5 times the capacity. A 5C battery that was 75 kW could generate 375 kW (500 hp), where a 17 kWh battery could only generate 85 kW (114 hp).
I used 5C as an example, as it is pretty close to what both the Clarity and the Tesla appear to draw, given their max power figures. The Tesla has a bit over 500 hp and the Clarity can draw about 120 hp from the battery (180 is motor rating, but that requires engine to be running). Most Li-ion allow discharge between 2C and 20C discharge depending on battery chemistry, and charging at less than 2C. Energy density and Power Density tend to work against one another, so the 20C discharge battery will likely be heavy and not many kWh range, where as the 5C discharge battery is relatively light and more kWh.
With EVs, a larger battery pack, given same battery chemistry, almost always equates to more power. This is why you see performance versions of the Tesla getting larger battery packs. Of course the motor, wiring, cooling systems, etc have to be designed for the added power if it is used.
I used 5C as an example, as it is pretty close to what both the Clarity and the Tesla appear to draw, given their max power figures. The Tesla has a bit over 500 hp and the Clarity can draw about 120 hp from the battery (180 is motor rating, but that requires engine to be running). Most Li-ion allow discharge between 2C and 20C discharge depending on battery chemistry, and charging at less than 2C. Energy density and Power Density tend to work against one another, so the 20C discharge battery will likely be heavy and not many kWh range, where as the 5C discharge battery is relatively light and more kWh.
With EVs, a larger battery pack, given same battery chemistry, almost always equates to more power. This is why you see performance versions of the Tesla getting larger battery packs. Of course the motor, wiring, cooling systems, etc have to be designed for the added power if it is used.
i should have said motor hp is twice not battery ... thinking writing disconnect
Pushmi-Pullyu
Well-Known Member
Well, the Model X's much higher capacity battery pack can provide more than twice the power as the Clarity PHEV's. But the biggest difference is that the Model X's electric motor(s) will provide much more horsepower on demand. Of course there are a host of other engineering differences required for that, from an EV inverter capable of handling that much electrical power, to wiring and other power electronics (and fuses) also capable of handling it.
Any PHEV is a compromise between a BEV and a gasmobile. With compromise generally comes lower power. Tesla cars don't compromise; they are pure BEVs, and engineered to provide high acceleration performance. Of course, Tesla cars are also a lot more expensive than the Clarity PHEV, so it's not like the Clarity doesn't have its advantages.
Again, with EVs, battery size and power are crucial. The bigger motors in the Tesla do nothing without the larger battery to provide the power.
Tesla was sued and forced to settle in Norway by lying about power by advertising the motor power when the batteries were not able to provide the specified power. Teslas are fast as they have big batteries with motors to match. The two are equally important.
Tesla was sued and forced to settle in Norway by lying about power by advertising the motor power when the batteries were not able to provide the specified power. Teslas are fast as they have big batteries with motors to match. The two are equally important.
Pushmi-Pullyu
Well-Known Member
Perfectly true, but the question was what are the engineering differences between the Clarity PHEV and Tesla's Model X.
Look at it another way: A chain is only as strong as its weakest link. A car's entire powertrain must be able to handle and deliver X amount of power for it to accelerate strongly. A battery pack is only one link in that chain. Of course, the same is true of the motor, the inverter, the reduction gear, the driveshaft(s), and every other part of the powertrain.
PHEV Newbie
Well-Known Member
After my road trip, I know I don't want a BEV--at least not for a long time. With the Clarity, the small gas tank takes about a minute to fill and I don't have to think about where the next charging station is. I just pull off the highway whenever I feel like it. Off and back on in about 5 minutes. With any BEV, it takes much longer (minimum 30 min on a Tesla Supercharger) and that would become infuriating after the first couple of stops. The huge loss of range in the cold makes them even worse for road trips in the winter. Clarity was designed to be practical today. All electric for everyday use and a nice cruiser for road trips. It's fuel efficient for both electric and gas drives and yet is roomy and luxurious. There is nothing like it on the road. The closest is the Volt but it is a less luxurious and smaller. Until there's a BEV that gives you over 250 miles (in hot and cold weather) on a 5 minute charge, I'll stick with PHEVs, which will hopefully just get better in the next few years.
Technology wise ev drivetrains are similar. It's the system sizing, economy versus performance. The Honda system is designed to fit into exiting cars and provide economy, this is why the Clarity, Accord, and Insight share the same system. It is just sized differently for each vehicle. That makes it cost friendly for volume production.
A high performance design like the Telsa, and other upcoming high end vehicles use much larger output motors and large battery packs for greater electrical current output. More batteries means more current output since you can have more parallel current draw from a bigger pack. This is when you don't worry about cost.
A high performance design like the Telsa, and other upcoming high end vehicles use much larger output motors and large battery packs for greater electrical current output. More batteries means more current output since you can have more parallel current draw from a bigger pack. This is when you don't worry about cost.
Pushmi-Pullyu
Well-Known Member
This is why I thought PHEVs would sell much better than BEVs until battery tech improves to the point that a BEV can be charged to 80% in, let's say, 10 minutes or less.
I'm very surprised that BEV sales meet or exceed PHEV sales. I guess a lot of people out there just aren't using them for long trips. Probably a lot of people with the so-called "hybrid garage"; one BEV and one gasmobile in the family's garage, and they use the gasmobile for long trips.
KentuckyKen
Well-Known Member
Best overview of the Clarity and PHEVs I’ve read. Exactly why I bought mine.
Honda should hire you you do their marketing.
You should change from PHEVnewbie to PHEVninja!
PHEV Newbie
Well-Known Member
You're too kind KentuckyKen
. Nonetheless, your comment does emphasize the poor understanding of the public on what PHEVs are all about. I've read the comments left on car reviews and there are doozies. The most common are: "Too expensive" (Hey, learn about the incentives that can make them cheaper than similarly appointed ICE and hybrid cars. Besides, for most people running on electrons is much cheaper than gas.); "Why buy this when hybrids have better mileage?" (Hybrids don't allow practical electric-only driving and the Clarity mileage is not that far off from similar sized hybrids); "Too ugly" (Clarity is all about efficiency. Truly aerodynamic cars look cool to me but I get that beauty is in the eye of the beholder).
dstrauss
Well-Known Member
One of my pet peeves about reviewers, but I think I understand it a little bit now after seeing mine parked next to a Lexus sedan (don't know the model). The Clarity looks like a cross between a techno-hybrid (Prius Prime) and a sports car wannabe (like a four door Mustang) with an overall forward leaning wedge to it. Had they been willing to suffer a few miles of aerodynamics for a more classic sedan look like a modern Lexus, BMW, etc. design, they would have had a runaway hit, at least among the group of yuppie wannabes...
Are you saying yuppie wannabes actually knew the Clarity existed, but selected a Lexus or BMW because they didn't like the Clarity's looks? Now if Beyonce or Tom Brady was tooling around in this Clarity, it would look really rad to those yuppie wannabes. It took a while for the Clarity's looks to grow on me even though I drive a more radically styled 1st gen Honda Insight.
As you might expect from one who loves his 1st gen Insight, I was hoping this Clarity concept car would someday be gracing our garage. It would certainly make the current Prius look old.
Pushmi-Pullyu
Well-Known Member
That concept car certainly looks very striking, but I'm not sure a car with no passenger side door, nor any obvious way to change the rear tires, would be all that practical.
dstrauss
Well-Known Member
No, just saying those are the yuppie-mobiles of choice (middle-agers as well) and that styling would bring them in.
I would buy this two-door model of the Clarity today. It looks good.As you might expect from one who loves his 1st gen Insight, I was hoping this Clarity concept car would someday be gracing our garage. It would certainly make the current Prius look old.
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