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Comment by cloudfudge | Hacker News Reader

From the donutlab page:

  > It can be charged to full in just five minutes without limiting charging to 80%, and supports full discharge safely, repeatedly, and reliably.

From the motorcycle youtube video[1]:

  > delivers up to 370 miles (600 km) of range and adds up to 186 miles (300 km) in under 10 minutes

One is claiming 100% in 5 minutes, and the other is claiming ~50% in 10 minutes. Why are their claims so different?

[1] https://www.youtube.com/watch?v=cy_mXYItqXU

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To charge the average Tesla in 5 minutes you need about 1MW and cables as thick as a forearm.

1 MW chargers don't look any bigger than standard chargers.

https://insideevs.com/news/761403/byd-thousands-megawatt-cha...

The thickness of the cables is often due to their water cooling. Transferring 1 MW at 99.9% efficiency means 1kW escaping as heat.

That's about the same as a hair dryer. Maybe I can save time by charging my car and setting my 'do simultaneously.

that depends. transferring 1 MW at 1 MV produces very little heat

1 megavolt means huuuge spark gaps, I'd say no less than 20", given dry air. This also means very thick insulation, very bulky and expensive switches and breakers, etc.

Tesla 3MW charger uses 1250V DC: https://en.wikipedia.org/wiki/Megawatt_Charging_System

Liquid-cooled charging cables are a thing. too; one of many: https://www.mouser.com/new/phoenix-contact/phoenix-contact-5...

Yes, but a car can't use electricity at 1 MV and converting the megawatt back to something lower than 1 MV still produces a lot of heat.

Vehicle battery packs are 400-800V today; not 1MV.

One is what the battery is capable of given a favorable environment, the other is what you can get in the environment of that motorcycle?

If might be for example that in the motorcycle the battery or the other components that have to handle the charge current cannot dissipate heat fast enough to allow charging with the maximum current the batter allows. In an EV the pack shape probably has a higher surface area to volume ratio making it cool better, and an EV might also be able to actively cool it.

Don’t bigger batteries allow faster charging because they can absorb current faster?

Perhaps the problem is the size of the battery being limited in a motorcycle.

The first quote gives it in terms of the capacity, “to full,” and for the second cloudfudge has helpfully computed that for us.

Verge motorcycle said they made it longer on purpose... I dunno why. Their larger battery size charges faster. They may have done some stuff to save money on the smaller 10min charging version, and maybe not as much money saving on the larger battery that charges faster.

Temperature thresholds, maybe the bike has active cooling?

Or maybe swags since this is vapor. I look forward to finding out.

It could just be me, but that video looks like AI.

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