# Forums

## Do superchargers still charge fast when STARTING above 50%?

This is from Wikipedia regarding superchargers: “They take about 20 minutes to charge to 50%, 40 minutes to charge to 80%, and 75 minutes to 100% on the original 85 kWh Model S.”

If my car has been parked for hours at 70% and I bring it to a supercharger, will it take less than 20mins to get to 90ish percent? Or does the ‘50% in 20mins’ rule only apply if you’re way below 50%?

I originally thought speed slows down due to heat build up of the battery (from charging), not the current power at the moment of charging.

NKYTA | 14 December 2019

Depends on what car you have. Depends on what level of SC you are at. Level I, II, III
0-80 % is fast, anything above is pretty slow, for most Tesla’s.

Frank99 | 14 December 2019

No.

Think of a LiIon battery as an elevator. When there's no one in it, people can enter quickly. Similarly, when the battery charge is low, it charges rapidly. When the elevator is half full, getting more people in is slower - similarly, the charge rate starts to slow down when the battery is about 50% full. When the elevator is almost completely full, getting more people in is a very slow process - similarly, the charge rate is vastly slower when a battery is nearly full.

If you pull into a Supercharger with your battery above 50%, you will NOT get the maximum charge rate. This isn't a matter of the battery heating up ( the Tesla Battery Management System will cool the battery as necessary); it's simply the physics of charging a LiIon battery. If you pull into a Supercharger with a 90% charged battery, you'll get a very slow charge rate, the same as if you'd been there for the last 45 minutes charging up to 90%.

So, to answer your question, "50% in 20 mins" only applies if you pull into the supercharger with between 5 and 10% battery charge, and will only take you up to 50-60% charge before the rate slows down. Pulling in at 40% means that you'll get full charge rate for a few minutes, taking you up to 50-60%, then the charge rate will slow down.

TeslaTap.com | 15 December 2019

These charts also help to show how the charging rate is affected by SOC: https://teslatap.com/articles/supercharger-superguide/#tapered

As you can see the power drops off as you go past 50% or so. This varies depending on the model and battery size, as the Model 3 batteries are designed differently than others. Smaller pack sizes do not achieve these results either. They take longer to get the same amount of energy but end up staying about the same amount of time, as they need less energy to fill up.

jimglas | 15 December 2019

Thanks for that TT
Nice article for us "late adopters"

WoW TT, TY from a new purchaser, CT on order.

So, even though it will PROBably be moot by the time CT comes out, which batt pack would be comparable FOR the CT? Which X designation would be in a DM AWD.....? Thanks again....

russell120k | 15 December 2019

Wow, thanks guys. This answers my question.

TeslaTap.com | 16 December 2019

@BadgerErickson - Great question, but until we instrument a Cybertruck, we will not know the taper curve. My guess is Tesla will be on its fourth generation cell design for the Cybertruck and Roadster 2020 which could operate differently than current cells.

Uncle Paul | 16 December 2019

A little tip. If you select the Supercharger icon as your destination, your car will pre-condition your battery to get the quickest charge possible when you arrive.

As others have said, your battery charges quicker from a low state of charge (but above 10%) than as it gets fuller.

Every battery, and every Supercharger, has their own curve, depending on its technology. Owners tend to learn the most efficient times to most quickly charge up their cars. You can watch your car supercharge rate on the display on on your smart phone.