First Cybertruck charging speed test on true V4 Supercharger confirms Tesla's 4680 battery is the problem

The first true V4 Supercharger station of Tesla is up and running in California, delivering up to 500 kW output to its only passenger vehicle that can take it, the Cybertruck.

Despite having a modern 800V powertrain, however, the first Cybertruck charging test at a true 500 kW V4 stall was somewhat of a disappointment. Granted, Tesla showcased that the V4 Supercharger was able to deliver 500 kW to the Cybertruck with a short video, but "short" is the key word here, as the electric pickup was only able to sustain that charging rate for a few brief seconds.

According to Tesla's Wes Morrill, the Cybertruck can now "recover up to 44% in 15 mins" on a V4 stall, if it comes with a low state of charge and preconditioned battery. While faster than on a V3 Supercharger, that is still a far cry from the 18-minute 10%-80% charging speed that Tesla's lead engineer Lars Moravy teased during the first Cybertruck reviews.

Granted, Tesla shows a few seconds where the Cybertruck takes 500 kW and charges with the speed of 1441 miles recovered per hour. The Cybertruck charging limiter was on, however, and the software still showed 35 minutes to reach an 80% charge. This is not all that different from the current 40 or so minutes that the Cybertruck takes on a V3 stall, even on the upgraded 325 kW ones that come with V4 piles but a V3 cabinet.

In fact, a 35-minute Cybertruck charging session to 80% capacity recovery of its 123 kWh battery means a sustained charge rate of about 170 kW. Given that the Cybertruck charging curve so far maxed out at a bit over 150 kW on average, even the 500 kW V4 Supercharger is only able to improve its charging speed by 10%-15%. In fact, Wes Morrill confirmed that, saying that the true V4 piles charge the Cybertruck just 13% faster.

This is still woefully slow when compared to other electric vehicles with an 800V architecture. Even if Chinese EV makers that already flaunt batteries with 10-minute charging times are discounted, Hyundai's electric vehicles sold in the US can sustain average charging rates of over 220 kW. The Ioniq 6, for instance, can recover more than 900 miles of range per hour on a suitable fast charger.

This only leaves the usual suspect as the culprit behind the disappointing Cybertruck charging curve, its second-gen 4680 battery. The thermal efficiency of Tesla's 4680 cell leaves something to be desired when compared to batteries by BYD or CATL. It can't maintain high charging rates for long without heating up to a point where the Cybertruck software throttles the input down to keep things cool and safe.

In a nutshell, even if Tesla's Supercharger network consisted only of true 500 kW V4 stalls, the average charging speed of its vehicles wouldn't improve much because it only offers one 800V passenger vehicle, and with a thermally challenged 4680 battery at that.

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