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New to Tesla: Distance added per hour of Destination Charge - kW, MPH, Amps, etc

SSedan

Active Member
Jul 24, 2017
2,948
2,589
Greenville Wisconsin
So, am I correct in hearing that there is no higher amperage on board charger available now? I have dual 40 amp chargers in my model s now, 80 amp charging, 19.2 kilowatt, better than 60 miles an hour. I would not be happy with half that speed! So, really, I can't get more/faster charging in the new cars?

I think they are 48amp and you have to consider efficiency gains which will add a few miles per hour at the same charge rate.
Yes it will be slower but with the extra range and efficiency I don't think you will be impacted by it.
 

cypho

Member
Dec 20, 2018
800
987
USA
I am seeking to make the transition to EV, and planning to order a Model S within a few weeks. I have read many of the threads on this forum which have been an invaluable source to learn about charging.

I am specifically interested in charging at vacation destinations where I may spend extend periods of time, and where a Supercharger would not be realistic, so please assume no access to Supercharger in this scenario. I will likely have easiest access to Tesla Destination Chargers (16kW) and ChargePoint (6 kW).

As I understand it kW determines the flow, and can be calculated by..
Volt x Amp = Watts

At home my electrician says my Tesla wall charger will..
1) 240 V x 60 Amp = 14.4 kW

Tesla Destination Level 2 chargers
2) 208 V x 80 Amp = 16.6 kW (listed on Tesla Site)

ChargePoint
3) Not sure, but listed as = 6 kW

In two of the scenarios above the onboard charger, which is 48 Amp / 11.5 kW, is the limiting factor. I have confirmed with Tesla that no upgrade is available (at least as a factory order).

My real question is how do I translate the kW to miles added per hour. I have read things on this forum such as "you can charge at 208 V * 48 A = 10 kW, or about 30 miles per hour of charging". Is there some simple conversion that I am missing that allows my to make this leap from 10 kW to 30 mph of charge, or in the examples above the 11.5 k limited by car or 6kW by ChargePoint to miles added per hour.

Thank you

If you are starting with charging stations kW rating, the easiest way to do the math is to divide your battery size, by the kW of charger.

Model S has a 100 kWh battery. A 10kW charger will fill it up (0%-100%) in 100 kWh / 10kW = 10 hours

If you want to convert that miles per hour, just divide your range by the charge time. Model S has 380 mile range, so 380 miles / 10 hours = 38 mph (for a 10kW charger)
 

David29

Supporting Member
Supporting Member
Aug 1, 2015
2,268
1,961
DEDHAM, MA
I find it simpler to think in terms of percentage. Like many other people, I keep my battery state of charge indicator on %, not miles. At my house, my Tesla Wall Connector provides 40 amps, which results in a charging rate of 13%/hour for my 70 kWh battery. But for mental calculations, I use 10% per hour. That way, when i am estimating the time to reach a certain state of charge, I am conservative, and it allows for fluctuations in the source voltage. E.g., let's say I plug in after driving the battery down to 40% and want to charge it to 70%. i estimate it it as 3 hours of charging and set the start time accordingly. If it finishes a few minutes early, that is OK. And if I pre-heat or pre-cool the car while it is still charging, my calculation allows for some margin that can usually accommodate the portion of the charging current diverted to the HVAC system. Imprecise, yes, but practical.
I rarely use public level 2 charging stations, but when i do the 10%/hour is also fairly accurate, even though the charge rate is actually lower (usually 30 amps or 7.2 kWh).
In my case, i find having a figure for % to be simpler. If i want to use it for miles, I also know that 10% is roughly 24 miles at the EPA rated capacity.
 

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