Last month, a 2024 Subaru Solterra came into our service department on Auto Center Drive after its owner had driven to a Tesla Supercharger station near the Ontario Mills mall expecting to charge, only to find his adapter was incompatible with the station's updated hardware. He had purchased a third-party adapter based on outdated forum information and made a 20-minute detour off the 60 freeway that ended with a 12 percent battery and no charge. The correct Subaru-approved NACS adapter was available at our parts counter for $210. The third-party adapter he purchased online cost $85 and did not work.
The Subaru Solterra's access to Tesla's Supercharger network is one of the most meaningful practical upgrades the vehicle has received since launch, and for Inland Empire owners it changes the daily and long-distance charging calculus significantly. The Supercharger network's density across San Bernardino and Riverside Counties, with stations near Ontario Mills, the Victoria Gardens area in Rancho Cucamonga, and along the I-15 corridor toward Las Vegas, fills gaps that the existing CCS network leaves in ways that matter for real-world Solterra ownership.
What makes this transition more complicated than a simple adapter swap is that NACS compatibility on the Solterra involves specific hardware, software, and procedural requirements that vary depending on model year and current software version. Owners who approach a Supercharger station without understanding these requirements run into exactly the kind of experience the owner above encountered, a wasted trip and a charging session that never happened.
The Inland Empire's driving environment adds another layer of consideration. Long stretches between destinations, summer temperatures that affect battery range and charging behavior, and the specific mix of highway and surface street driving between the 10, 15, 60, and 210 freeways all influence how Solterra owners should plan their charging strategy now that Superchargers are accessible. This guide covers what NACS compatibility actually means for the Solterra, how to use the Supercharger network correctly in the Inland Empire, and what to verify before your first session.
What NACS Compatibility Actually Means for the Solterra
Hardware and Software Requirements
NACS, the North American Charging Standard originally developed by Tesla and now adopted broadly across the industry, uses a physically different connector than the CCS port the Solterra shipped with at launch. For current Solterra owners, accessing Superchargers requires the Subaru-approved NACS adapter, which connects to the existing CCS port and allows the vehicle to communicate with Supercharger hardware. This is not a universal adapter situation. The approved adapter is vehicle-specific and includes communication protocols that allow the Supercharger to authenticate the Solterra correctly and initiate a charging session.
Software version matters alongside the hardware. Solterra units require a specific firmware level to communicate correctly with Tesla's Supercharger network, and vehicles that have not received recent over-the-air updates may not authenticate successfully even with the correct physical adapter. Before attempting a first Supercharger session, verify your Solterra's software version through the vehicle settings menu and confirm it meets the current NACS compatibility requirement. Our service department can verify and update software to the required version if your vehicle has not received the relevant update automatically.
The charging speed ceiling at Superchargers is also worth understanding before the first session. The Solterra's onboard charger accepts DC fast charging at up to 100 kW, which means it will not use the full output of a V3 Supercharger capable of 250 kW. Charging behavior is governed by the vehicle's onboard charger, not the station, so the Solterra will charge at its maximum acceptance rate regardless of which Supercharger generation you connect to. In practical terms, a Solterra at 20 percent battery will reach 80 percent in approximately 35 to 45 minutes at a compatible Supercharger under normal temperature conditions, which is a meaningful improvement over the CCS network's availability and consistency in the Inland Empire.
Charging in the Inland Empire: What Solterra Owners Need to Know
Temperature and Range in San Bernardino County
The Inland Empire's summer heat introduces charging behavior that catches owners off guard if they are not expecting it. Battery thermal management is active in the Solterra during high-temperature charging sessions, which means the vehicle may limit charge acceptance rate while the battery cooling system brings cell temperatures into the optimal range. On a 105-degree afternoon in Ontario or Fontana, a Solterra that sat in a surface parking lot off the 60 freeway for several hours may take three to five minutes longer to reach peak charge acceptance than the same session would take on a moderate temperature day.
The practical implication is that pre-conditioning the battery before arriving at a Supercharger, using the Solterra's climate pre-conditioning feature while still plugged into a Level 2 charger at home if possible, reduces this thermal management delay and produces a faster overall session. For owners making the drive from the Ontario area toward Palm Springs on the 10 or heading up the 15 toward Barstow, pre-conditioning before departure is worth building into the routine during summer months.
Range behavior in Inland Empire heat deserves equal attention. Sustained highway speeds on the 15 or 215 combined with air conditioning running at full output in summer reduces the Solterra's effective range meaningfully compared to EPA estimates, which are calculated under moderate temperature conditions. Owners planning longer drives through San Bernardino County during summer should plan charging stops with a more conservative range buffer than the vehicle's range display suggests, particularly on stretches between Ontario and the high desert where elevation gain adds additional draw on the battery.
"The question I get most often from new Solterra owners is why the charging session did not start even though they had the right adapter," says Christine Nakamura, EV Technology Advisor at our Auto Center Drive location. "Almost every time it comes down to the software version not being current, or the Tesla account not having the vehicle added correctly through the app. Both are five-minute fixes once you know what to look for, but they are not obvious the first time you are standing at a Supercharger station with 15 percent battery."
A Solterra owner from Chino Hills came to us last summer after two unsuccessful Supercharger attempts at the Victoria Gardens station in Rancho Cucamonga. She had the correct adapter but the vehicle's firmware was one version behind the NACS compatibility requirement. A software update at our service department took 40 minutes. Her third attempt at the same Supercharger station worked immediately, and she has used the network regularly since without issue.
Setting Up Your Tesla Account and Finding Inland Empire Stations
Using a Supercharger as a non-Tesla vehicle requires a Tesla account and payment method registered through the Tesla app, even with the correct adapter and current software. The charging session is initiated through the Tesla app rather than the Supercharger station's screen, which differs from the CCS charging experience most Solterra owners are accustomed to. The steps worth completing before your first session are:
- Download the Tesla app and create an account if you do not already have one, adding a payment method before arriving at a station rather than during the session
- Add your Solterra to the Tesla app using the non-Tesla vehicle option, which registers the vehicle's charging credentials and allows the app to initiate sessions correctly
- Verify adapter seating fully before initiating the session through the app, as a partially seated adapter will prevent authentication even when all account and software requirements are met
- Start the session through the Tesla app rather than waiting for the station to recognize the vehicle automatically, as non-Tesla vehicles do not trigger automatic session initiation the way Tesla vehicles do
The Inland Empire Supercharger locations most relevant to Ontario area Solterra owners currently include the station near Ontario Mills off the 10, the Rancho Cucamonga station near Victoria Gardens off the 210, and the Eastvale station near the 15 and Limonite Avenue interchange. The I-15 corridor stations toward Las Vegas at Barstow and Baker are particularly useful for owners making the desert drive, and both are compatible with the current Solterra NACS adapter setup.
Schedule your NACS adapter verification and software check today by calling our service department or booking online at Subaru of Ontario, 1195 Auto Center Dr, Ontario, CA 91761. We will confirm your Solterra has everything it needs to use the Supercharger network correctly before your first session, and walk you through the Tesla app setup if you have not completed it yet. ⚡