My guess is this is spot on. I have been driving a 150 mile range Leaf for 3.5 years. It has no provision to charge to 80% or 90% like a Tesla. I charge it to 100%. When I first got it, 100% was 171 miles, 3.5 years later 100% is 165 miles. I think the 150 is going to be 150 miles usable similar to the Leaf.
I wouldn't get my hopes up. The standard battery is 52.7 kWh. A Rivian R1T gets ~2.2-2.5 mi/kWh, and a Tesla Model X gets around 2.7-3.0 mi/kWh. If we're generous and say this thing will have an average efficiency of 3.0 mi/kWh, that gives us a maximum range of 158.1 miles.
Obviously this is operating on an assumption on the efficiency, but if anything, I'm being generous with it I believe. A VW ID.4 gets anywhere between 2.6 and 4 mi/kWh, and is less box-shaped than our beloved Slate Truck. The Mustang Mach-E seems to average around 2.7-3.1. We'll have to see.
Hard to calculate where the efficiency is. Most of those are more aerodynamic than the slate, but the slate may be lighter weight than some due to the smaller battery. The bigger the battery in the same vehicle the lower the efficiency because you have to haul around that battery.
