🔋 The Extended Battery Decision (Poll: Which battery option suits you best?)

[AZFox]

BTW, have they said the difference in the weight of the two batteries?

As of five days ago:

Kylee from the Sales Agent Team gave a prompt and courteous reply.

Excellent questions!​

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We are just a few months shy of our production and sharing more design and material details about the overall build.​

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While I would love to provide the detail you are in search of we ask that you hold tight. We have many things in store.​

 

[AZFox]

There have been tests that show that weight alone has almost no effect on efficiency or range. I’d be surprised if there was much difference at all in efficiency between the two battery sizes

The calculation is based on published specifications.

 

[Dorbiman]

The calculation is based on published specifications.

Published estimates. But yes, I understand where the numbers come from.

 

[AZFox]

Published estimates. But yes, I understand where the numbers come from.

Maybe I should have chosen a better word.

Slate is claiming, but publishing those numbers, that the same energy that gets you 100 miles with a Standard battery only gets you 89.3 miles if you have an Extended battery.

I wouldn't call that negligible.

 

[Dorbiman]

Maybe I should have chosen a better word.

Slate is claiming, but publishing those numbers, that the same energy that gets you 100 miles with a Standard battery only gets you 89.3 miles if you have an Extended battery.

I wouldn't call that negligible.

For sure. That’s why I’m dubious of those claims. Based on every other EV in existence, I also expect to get about 12% less range than their EPA estimates, if not even less.

 

[AZFox]

For sure. That’s why I’m dubious of those claims. Based on every other EV in existence, I also expect to get about 12% less range than their EPA estimates, if not even less.

It's more difference than you'd expect, yes.

Another way of looking at it:

If you can get 40 miles of range on an overnight 110v charge of a Standard battery, the same charge would only get you 35.7 miles if you have an Extended battery.​

Advantage: Standard *
(* if Slate's published figures are accurate)

 

[KevinRS]

We just aren't going to find out anything more on range and battery pricing for at least a few months, the numbers we have seen are estimated EPA estimates coming from a computer model. Once they build the actual first final version trucks on the assembly line, they will be tested and real EPA estimated mileage numbers will be released.
The one part that will be disappointing I think is wind resistance. Most EVs besides the large pickups are highly streamlined, and the slate is going to suffer at high speeds more than them. Stop and go traffic will be fine, because of regenerative braking, but the faster you go the more wind drag.

 

[AZFox]

The one part that will be disappointing I think is wind resistance. Most EVs besides the large pickups are highly streamlined, and the slate is going to suffer at high speeds more than them. Stop and go traffic will be fine, because of regenerative braking, but the faster you go the more wind drag.

Big time.

Among all of the Battery Buzzkills I've looked into, highway-speed driving is the biggest surprise.

As speed doubles, the power needed to overcome drag increases by a factor of eight.​

Driving at high speeds affects EV range waaay more than I expected.

The shape of the Slate Truck is not exactly that of a Land Speed Racecar.

Surely the engineers know Drag Coefficient (Cd) for the Truck. I wonder if that information will be published.

 

[Driven5]

150 miles on 52.7 kWh is 3.2 miles per kWh.

Try again.

 

[KevinRS]

Big time.

Among all of the Battery Buzzkills I've looked into, highway-speed driving is the biggest surprise.

As speed doubles, the power needed to overcome drag increases by a factor of eight.​

Driving at high speeds affects EV range waaay more than I expected.

The shape of the Slate Truck is not exactly that of a Land Speed Racecar.

Surely the engineers know Drag Coefficient (Cd) for the Truck. I wonder if that information will be published.

This got me looking at how the EPA range is determined, they test on a dyno, and run a city cycle, and a highway cycle, they typically multiply by 0.7 to account for AC use and aggressive driving, and they weight the city at 55% and highway 45% and give 1 combined range number. Looking beyond that it gets really technical.

 

[AZFox]

Try again.

Ha! Well, that's embarrassing. 🤦
I took your advice and tried again.
Sure enough, it's negligible (rounds to zero, favors Extended).

240 miles on 84.2 kWh is 2.8503 miles per kWh.
150 miles on 52.7 kWh is 2.8463 miles per kWh.

2.8503 divided by 2.8463 is 1.0014

So Slate's published figures cypher to 0.14% more range (1.4 miles per 1,000) with the Extended Battery option.