Tesla Model X Buyer Finds Hidden Doubly Quick 72A On-Board Charger Option

Imagine a major automotive company hiding an optional feature because it does not want buyers to choose it.

That, by its own admission, is exactly what Tesla has done for buyers now invited to privately configure their Model X which comes standard with a 48-amp on-board single charger (OBC) which restricts charge times compared to Model S with dual chargers.

“We are still recommending the 48-amp AC charger so we hid the High Amperage Charger Upgrade option,” said a Tesla representative of an irrevocable choice that costs Tesla $1,000 per order not to sell, and which locks in a slower AC recharge rate for the life of the Model X.

This discovery was made this week by a buyer who found the option not immediately presented by the online configurator Tesla calls its Design Studio. The revealed option lets buyers select a 72-amp OBC that could potentially chop recharge times from high-amperage AC supply equipment by as much as half compared to the standard 48-amp OBC.

Until this hidden option box appeared, it had been reported for several weeks by early buyers that the Model X was equipped only with a 12-kilowatt, 48-amp single phase charger – much less than the Model S’s dual 10-kw chargers. This was the only choice Tesla presented.

Why this was hidden is not immediately clear. If buyers don't choose it at time of ordering, it permanently determines a slower than possible home recharge time.

Why this was hidden is not immediately clear. If buyers don’t choose it at time of ordering, it permanently determines a slower than possible home and potentially public AC recharge time.

What other technical reasons Tesla had for hiding the 72-amp OBC choice are not immediately clear, but the issue for buyers is this: For home or possibly public AC charging, the bottleneck – or enabler – in current flow and charge speeds is the on-board charger. Supercharging publicly is not affected as supercharging bypasses the on-board charger.

Compared to Model S, the Model X looked like it was nearly crippled out of the gate in home or public AC recharge times if using higher than ordinary amperage electric vehicle supply equipment (EVSE).

For example, Tesla has offered an 80-amp high-power Wall Connector that can zap Model S cars capable of accepting all of its 80-rated amps, but the Model X appeared unable to to take its full flow with a 48-amp OBC.

The discovery was made in spite of Tesla’s attempt to hide it. By typing “charger” while on the Design Studio page without quote marks, the $1,000 optional 72-amp OBC presented itself from out of hiding on the ordering screen.

The find was made by one person attempting to wire his home for a second Tesla, and in conversing live with Tesla personnel, he was tipped off that the hidden option was there. There were no clues otherwise online, and forum commenters have been left not knowing what to conclude except Tesla did not want people to choose it.

The Wall Connector, $750, requires a 100-amp line at home. Set up properly, it charges Model S at up to 58 miles range per hour, says Tesla.

The Wall Connector, $750, requires a 100-amp line at home. Set up properly, it charges Model S at up to 58 miles range per hour, says Tesla.

And unlike a benign and meaningless “Easter egg” in a Model S car such as an infotainment screen that playfully converts to the display for James Bond’s Lotus Esprit sub, this hidden surprise does make a big difference.

As the 72-amp OBC is wired from the factory, Tesla says it cannot be retrofitted as is the case with the $2,000 Model S Dual Charger which doubles miles-per-hour charge rates from 29 to 58.

For Model X buyers, no retrofit option means it’s speak now or hold your peace. People setting up their high-five to six-figure Model X are locked in for the life of the car by Tesla’s shenanigans, as some have put the automaker’s behavior of not making the option clearly visible.

Initially, this same buyer who reported the discovery had posted on a forum that he was disappointed that the Model X was hobbled with the 48-amp single charger, as recharge times would be significantly slower than a Model S with dual chargers and same battery.

According to Tesla, 160 miles range at 40 amps takes 5 hours and 26 minutes to put in. The same 160 miles at 80 amps takes 2 hours and 43 minutes.

Approximately speaking, and for simplicity’s sake, the difference between 40 amps and 80 amps is 100-percent faster. The difference between 48 amps and 72 amps is 50-percent faster. The difference between 72 amps and 80 amps (as with Model S) is over 11-percent faster.