danrjones
Well-known member
I did some napkin math and was able to calculate the near perfect EV, in terms of range and charge speed.
If you take the high voltage technology from something like the Taycan, but you use Tesla efficiency, and you oversize the battery, you can get some interesting results.
If you look at charging curves, the Tesla 3 LR can hit 250kW on V3 but only for a short time - 5% to about 25% then starts to ramp down. The Taycan charging curves I found manage to charge at 250 kW from 5% to about 50% then start to ramp down.
The Tesla S with 370 miles of range has a battery of 100 kWh. The Taycan will have a range around 220ish miles when rated, and it has a battery of 93.4 kWh. So there is a large efficiency difference but also the Taycan may have a big portion of its battery locked off.
So I want to keep that 370 miles of range but maximize that 250+ charge speed. If we design a vehicle that only allows you to use the battery from 10% to 60%, we would need a battery obviously twice the size. So you would have a 200 kWh pack with the first 10% locked off, and the last 40% locked off. But if I understand correctly, a battery that is twice the size could possible accept twice the energy. So if the Taycan can take 250 kW right now, a battery pack twice that size could theoretically take 500 kW if you could keep it cool. Individual cells would still be getting the same amount of power as the 100 kW battery at 250 kW, just there are twice the cells. Using EA chargers as the current max, our car with the 200 kWh battery could then take the max of 350 kW for that allowed 10-60% section of the battery with no ramp down. Simple math gives us a recharge time of 17.1 minutes to "fully" charge the battery for 370-ish miles. That's pretty good! I've taken the liberty of a few assumptions but it presents an interesting example. Right now it would be too expensive and you'd have to fit it all in the vehicle. Online data says Tesla battery cost is currently 110ish per kWh, so a 200 pack would be $22,000. So perhaps that's not so outlandish after all?
True, if they unlocked the top of the battery you would end up with 500+ miles of range. I guess it would be a marketing thing, but to be able to say the battery charges "fully" in 17 minutes for 370 miles of range would be a big deal. And if somehow you could supply 500 kW, it would "fully" charge in 12 minutes for aprox 370 miles of range.
Is this crazy talk or the future?
If you take the high voltage technology from something like the Taycan, but you use Tesla efficiency, and you oversize the battery, you can get some interesting results.
If you look at charging curves, the Tesla 3 LR can hit 250kW on V3 but only for a short time - 5% to about 25% then starts to ramp down. The Taycan charging curves I found manage to charge at 250 kW from 5% to about 50% then start to ramp down.
The Tesla S with 370 miles of range has a battery of 100 kWh. The Taycan will have a range around 220ish miles when rated, and it has a battery of 93.4 kWh. So there is a large efficiency difference but also the Taycan may have a big portion of its battery locked off.
So I want to keep that 370 miles of range but maximize that 250+ charge speed. If we design a vehicle that only allows you to use the battery from 10% to 60%, we would need a battery obviously twice the size. So you would have a 200 kWh pack with the first 10% locked off, and the last 40% locked off. But if I understand correctly, a battery that is twice the size could possible accept twice the energy. So if the Taycan can take 250 kW right now, a battery pack twice that size could theoretically take 500 kW if you could keep it cool. Individual cells would still be getting the same amount of power as the 100 kW battery at 250 kW, just there are twice the cells. Using EA chargers as the current max, our car with the 200 kWh battery could then take the max of 350 kW for that allowed 10-60% section of the battery with no ramp down. Simple math gives us a recharge time of 17.1 minutes to "fully" charge the battery for 370-ish miles. That's pretty good! I've taken the liberty of a few assumptions but it presents an interesting example. Right now it would be too expensive and you'd have to fit it all in the vehicle. Online data says Tesla battery cost is currently 110ish per kWh, so a 200 pack would be $22,000. So perhaps that's not so outlandish after all?
True, if they unlocked the top of the battery you would end up with 500+ miles of range. I guess it would be a marketing thing, but to be able to say the battery charges "fully" in 17 minutes for 370 miles of range would be a big deal. And if somehow you could supply 500 kW, it would "fully" charge in 12 minutes for aprox 370 miles of range.
Is this crazy talk or the future?