From Subaru's technical data for the Solterra on its Canadian website, it states that their StarDrive e-Axle has an efficiency of "3.1 mi/kWh," with an asterisk noting the following: "Based on Natural Resources Canada’s (NRCan) approved guidelines. Refer to NRCan’s Fuel Consumption Guide available at Fuel consumption ratings search tool
for more information."
Referring then to NRCan's site for the official data on the Solterra yields its combined efficiency rating: 20.3 kW (kW/100 km). Converted, this comes to 3.06 mi/kWh, which indeed rounds up to 3.1. This efficiency would infer a combined range of ~199 miles to 0%, or ~184 miles if including <0% 'turtle mode.'
Assuming a ~65 kW net battery capacity, this simply 'does not compute' when comparing these figures against the vehicle's NRCan rated range: 360 km [223.7 miles]; just as it does not compute
with the slightly higher U.S. EPA figures, either. Neither the NRCan site nor its U.S. EPA equivalent (fueleconomy.gov) state whether their ratings apply to the 18" or 20" wheel models, but based on what we know of the advertised specs (which come from government ratings), I have a hunch that NRCan—unless their test cycle differs fundamentally from EPA's—refers to a Limited or Touring model, while perhaps EPA references a base model with 18" wheels.
In fact, the officially estimated range figures from either the US or Canada only compute
when you multiply the official combined efficiency figures by the full or nearly full gross battery capacity.
NRCan: 3.06 kWh/mi x 72.8 = 223 miles range (which coincidentally is the officially advertised figure for higher trim models)
U.S. EPA: 3.23 kWh/mi x 72.8 = 235 miles range (a hair under 3% higher than officially advertised figures for lower trim models)
I increasingly suspect that Toyota made a last minute decision to increase the unusable
portion of the battery's buffer (the portion between ~65 kWh and 72.8 kWh) well after all of the pre-production checkboxes had already been ticked (such as EPA testing, etc). While including usable range below 0% in official range ratings may be a bit deceptive, it's not beyond the pale. Including some portion of an unusable
buffer in these ratings, however, would be—by any objective interpretation—because it's akin to cooking the numbers.
But at this point, it's the only thing that logically explains all of the discrepancies, including the commonly observed poor range—even in decent weather—and the bizarre GOM readings which seem to develop a 'hole in the tank' at SOC's <50%. The decision to change battery suppliers, I suspect, also likely came late in the game and probably factors in to some of this.