Tesla's battery day

[dbsb3233]

Because they're interchangeable, you won't be able to get near the cost recovery needed for those expensive (and heavy) panels on trailers when not being towed by electric trucks. (Frankly, I kinda doubt the economics would even work for electric trucks either.)

While an interesting idea, I just doubt it's economical or practical.

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[dbsb3233]

For what it's worth regarding battery trucking. The Nikola refuse lists a 750kWh battery and a 150 mile range. Granted, it is designed for picking up trash, so it's mostly stop and go.

Still it gives an idea in the crazy amount of energy needed.

Wow. So 0.2 miles/kWh (5 kWh per mile), with significant regen help for lots of slow stop-go driving. Even worse than I thought.

 

[dbsb3233]

Wouldn't get anywhere near that on my vehicles - I have a garage. ?

 

[dbsb3233]

Other way around... says "<2 kWh/mile". So the 500 mile version must have ~1000 kWh battery.

And all unproven so far, IIRC. They keep pushing the timeline back.

Don't see anything on downtime for charging either. That's a key part of the economics.

I have wondered if we'll see multiple battery packs on bigger vehicles, with a charge port for each. Plug both in at the same time to cut the charge time in half. Of course, that requires even more charger power.

 

[JCHLi]

Other way around... says "<2 kWh/mile". So the 500 mile version must have ~1000 kWh battery.

And all unproven so far, IIRC. They keep pushing the timeline back.

Don't see anything on downtime for charging either. That's a key part of the economics.

I have wondered if we'll see multiple battery packs on bigger vehicles, with a charge port for each. Plug both in at the same time to cut the charge time in half. Of course, that requires even more charger power.

Nikola says they can change at 350 DCFC. The Refuse trucks probably have a set route each day, then change over night.

I'm not sure how the math on changing works, but if the battery is 750 kWh and even at 350 kWh... It would take over 2 hours to change? Seems like a few more hurdles for long haul trucking.

 

[dbsb3233]

Nikola says they can change at 350 DCFC. The Refuse trucks probably have a set route each day, then change over night.

I'm not sure how the math on changing works, but if the battery is 750 kWh and even at 350 kWh... It would take over 2 hours to change? Seems like a few more hurdles for long haul trucking.

If there's no charge curve taper. There probably is. But even if that makes it 5-6 hours, that still works for that application. I agree that 150 mile city driving is probably possible. With such slow driving and lots of regen, that could be an 8 hour shift (if the trash transfer station or dump is fairly close, anyway).

 

[JCHLi]

I'm thinking most trailers have a roof about 400 sq ft. And current average for solar per sq. Ft. Is 15 watts per hour. So maybe 6 kWh under direct sun. This would taper off in the morning and evening so maybe.. maybe the roof would generate 30 kW. Even at 2 miles per kW that would net 60 miles.

Then you have to consider the extra weight which would decrease range, but even more of an issue, it would reduce the amount you could haul due to weight restrictions.

(Feel free to correct/critique my numbers)

 

[JCHLi]

I know the Hyundai sonata hybrid has a solar roof, they estimate on a sunny day you'll get 2 miles extra. So provided every day is sunny you'd get ~700 miles a year.. didnt know Tesla had a solar roof.

 

[dbsb3233]

Even at 2 miles per kW that would net 60 miles.

Other way around... 2 kWh per mile. So 15 miles. In clear skies with high sun angle. Less in the morning, or late afternoon, or cloudy.

 

[JCHLi]

Other way around... 2 kWh per mile. So 15 miles. In clear skies with high sun angle. Less in the morning, or late afternoon, or cloudy.

Ah yes, makes more sense. 2 kWh per mile or .5 mile per kWh..

 

[JCHLi]

Yup, not very cost effective at all.

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