Engineering deep dive: Slate EV truck chassis, body, battery, safety, suspension

[E90400K]

Look again. I had to put them in the corner of the rear window to avoid fender intrusion.

Indeed. I stand corrected. I was thinking maybe coach doors with hidden handles on the leading side of the door, which makes ingress and egress much easier

 

[cadblu]

I see Sandy was at the event. Wonder what he thinks?

Yes Sandy was there and he offered up his review on LinkedIn. In summary, he was “seriously impressed…”

 

[cvollers]

The 5-door Slate: dead on arrival.

Maybe Slate 2 will get a longer wheelbase and two more doors. And power windows/mirrors. But please don’t add screens.

 

[cvollers]

Agree, and what is holding back going to a 800V architecture? If it's cost, then perhaps that is indicative of the argument for the reasons why expensive BEV are expensive, they are built with better, more expensive components. How much really is being saved by deleting the fluff infotainment electronics and associated software?

I like the concept of decontenting the fluff, but any fresh BEV at this point should be nothing less than 800V.

I asked ChatGPT and got this result:

“1. Battery Size and Charging Speed Needs

• Smaller EVs typically have smaller battery packs (e.g., 30–50 kWh vs. 70–100+ kWh in larger EVs).
• These smaller packs don’t take as long to charge, even on 400V systems, so the time-saving benefit of 800V fast charging is marginal.

2. Cost and Complexity

• 800V systems require more expensive components, such as:
  • High-voltage inverters
  • More advanced insulation
  • Specialized charging hardware
• For low-cost EVs, keeping the bill of materials (BOM) low is essential. Adding 800V support increases cost without offering proportionate value to the target buyer.

3. Charging Infrastructure Compatibility

• 400V is still more common in public charging networks.
• Most users of small EVs charge at home or use slower public chargers, not ultra-fast stations where 800V would matter.

4. Thermal and Efficiency Gains are Smaller

• 800V systems reduce current for the same power level, which helps with thermal efficiency, but smaller EVs don’t draw high enough currents to significantly benefit.

In short, the advantages of 800V—faster charging, better efficiency at high power—are most useful for larger, long-range EVs. For small EVs, 400V is simpler, cheaper, and “good enough.””

 

[E90400K]

I asked ChatGPT and got this result:

“1. Battery Size and Charging Speed Needs

• Smaller EVs typically have smaller battery packs (e.g., 30–50 kWh vs. 70–100+ kWh in larger EVs).
• These smaller packs don’t take as long to charge, even on 400V systems, so the time-saving benefit of 800V fast charging is marginal.

2. Cost and Complexity

• 800V systems require more expensive components, such as:
  • High-voltage inverters
  • More advanced insulation
  • Specialized charging hardware
• For low-cost EVs, keeping the bill of materials (BOM) low is essential. Adding 800V support increases cost without offering proportionate value to the target buyer.

3. Charging Infrastructure Compatibility

• 400V is still more common in public charging networks.
• Most users of small EVs charge at home or use slower public chargers, not ultra-fast stations where 800V would matter.

4. Thermal and Efficiency Gains are Smaller

• 800V systems reduce current for the same power level, which helps with thermal efficiency, but smaller EVs don’t draw high enough currents to significantly benefit.

In short, the advantages of 800V—faster charging, better efficiency at high power—are most useful for larger, long-range EVs. For small EVs, 400V is simpler, cheaper, and “good enough.””

So Chap GP seems to confirm it's a cost issue, which makes my point that more expensive EV are expensive because they use better, more expensive components for better charging performance.

Chap GP just leads back to my concern about market acceptance. People on the lower income level of society don't own a single-family home that has access to private overnight EV charging. They will have to use the public DCFC network to charge their Slate, which is just 90 miles of usable range (20% to 80% SOC), which will take 30 minutes. To get to 150 miles of range at 100% SOC will probably take an hour or more. Drive 10,000 miles a year at 90 miles a clip and that's 56 hours spent fueling a Slate.

A Ford Maverick 2.0L Ecoboost has 400 miles of range per tank and at its EPA rating of 26 MPG, it will need around 24 fills of the tank to travel 10,000 miles per year. 24 tank fills at 5 minutes each is just 2 hours per year to fuel the Maverick.

 

[Chadsfantasygarage]

Maybe Slate 2 will get a longer wheelbase and two more doors. And power windows/mirrors. But please don’t add screens.

Yes that makes sense to me. Perhaps a long enough body to accommodate an optional inclosed 3rd row that can be converted back into a smaller pickup truck with a mid gate to allow for longer items without making the overall length too long?

 

[cvollers]

Yes that makes sense to me. Perhaps a long enough body to accommodate an optional inclosed 3rd row that can be converted back into a smaller pickup truck with a mid gate to allow for longer items without making the overall length too long?

I like your image but think it’s a little too long for what Slate might do. I doubt the bed will get longer than what they have now so the C pillar will have the same relationship to the rear door as the current B pillar does to the front door.

 

[metroshot]

I don't care if the battery is 400 or 800v.
I just want to access Tesla Superchargers where I normally charge my Mach E.
With such a small battery, it should be enough time to get a coffee or bathroom trip.

 

[Johnny-Longtorso]

Based on the specs I've seen this is very, very optimistic. (my guestimate being that's near 1k pounds based on ~ 65# for a 4x8 sheet of 3/4" MDF)

It may fit, but I don't see the suspension dealing with it, nor do I see it moving this material safely for more than a few blocks.

Am I wrong?

 

[cvollers]

Based on the specs I've seen this is very, very optimistic. (my guestimate being that's near 1k pounds based on ~ 65# for a 4x8 sheet of 3/4" MDF)

It may fit, but I don't see the suspension dealing with it, nor do I see it moving this material safely for more than a few blocks.

Am I wrong?

The quoted load rating is 1400 pounds.

 

[Johnny-Longtorso]

The quoted load rating is 1400 pounds.

Ah, OK.

So with me@ 240# that would be right on the edge.