Charging Speed per Voltage

[ajdelange]

How often are you going to drive 500 miles round trip everyday where you need to fully charge it everyday........................................

Seldom but one doesn't size electrical equipment to average demand - he sizes it to peak demand. For example the panel to which the charger is connected has a 200 A main breaker though I have never drawn more than 120A from that panel (though it has 1360 pole-amperes worth of breakers in it). With respect to the car I normally charge at 5 kW to 70% which is adequate for my low daily mileage and keeps me away from the utility's peak utilization charges but I can charge at 17 kW if I need to or want to. When would I want to? An example would be when doing a road trip where I'd like to depart with 90% and forgot to set the charge limit that high the night before. At 17 kW I can pick up the extra 20% in an hour and a quarter. Another example would be where the battery is cold and I want to pre warm it so I'll have full regen. The faster one charges the more waste heat there is for warming.

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[Revelation]

Seldom but one doesn't size electrical equipment to average demand - he sizes it to peak demand. For example the panel to which the charger is connected has a 200 A main breaker though I have never drawn more than 120A from that panel (though it has 1360 pole-amperes worth of breakers in it). With respect to the car I normally charge at 5 kW to 70% which is adequate for my low daily mileage and keeps me away from the utility's peak utilization charges but I can charge at 17 kW if I need to or want to. When would I want to? An example would be when doing a road trip where I'd like to depart with 90% and forgot to set the charge limit that high the night before. At 17 kW I can pick up the extra 20% in an hour and a quarter. Another example would be where the battery is cold and I want to pre warm it so I'll have full regen. The faster one charges the more waste heat there is for warming.

You totally missed the conversation. The person I was responding to was talking about how it would take 10+ hours to recharge the LR CT. There was no discussion about anything else. While you raise some valid points when it comes to charging, that is irrelevant to the OP's concern.

 

[ajdelange]

Maybe easiest to talk in terms of miles of driving per hour of charge time because of the different capacities of battery available.

That is a good way to do things subject to some caveats in particular that to come up with a miles per hour of charging rate you must know the watt hours the vehicle will consume when you drive it. This varies so we use a "rated" number for the car or truck. We don't know what that number will be for the CT but a 200 kWh battery and 500 mi EPA range suggest that its going to be around 400 Wh per mile equivalent to 2.5 mi/kWh. That's a reasonable number. Using it find:

A 15 A 120 V circuit is capable of 1.2 kWh and would add 3 miles per hour of charging
A 20 A 120 V circuit is capable of 1.9 kWh and would add 4.8 miles per hour of charging
240 V circuits can potentially provide from 1 kW to 19.2 kW (if the CT has 80 Amps worth of chargers) and thus allows charging at from 2.5 to 48 mi/hr. As 240 EVSE comes in so many varieties perhaps the formula kW = 0.8*Circuit_breaker*240/1000 will be useful. Added range is still 2.5*kW.

As suggested in # 18 you will want to size your EVSE according to the most charging you think you are going to want. There are many factors involved here including the price of electricity at home (which may vary with time of day or the presence of solar panels etc.) relative to at the nearest super charger (free SC is a factor, of course), the distance to the newest SC etc. Another big factor is the determination as to whether you think you will ever obtain a second Tesla or other BEV.

While it may be handy to think of charging rates in terms of miles it is overall best to think of the status of your battery in terms of its percentage charge. Percentage charge is easily translated into nominal miles. If the EPA range of the vehicle is 500 mi then clearly each percent of battery charge gained or lost represents 5 miles. You will also want to know what percent of the battery capacity 1 kWh represents. For A 200 KWH battery this is clearly 0.5%. Knowing this you can easily determine what percent of capacity is added at a given charge rate. If charging at 17 kW one is adding 8.5 % of capacity per hour. If one needs to add 20% it is going to take 20/8.5 or a bit over 2 hours to do that at 17 kW. One can get the same answer by noting that 20% of 500 is 100 miles, that 17 kW gives 42 miles per hour charging.

... now I’m wondering if I might need to upgrade to the higher range battery based on some quick-turnaround trips where I might not be able to fully recharge. I’m not a Tesla person so I need some explanation.

Battery size is another thing that you need to determine based on your peak demand. If you make 200 mile round trips where you cannot or do not wish to stop to charge then you will want one of the larger battery options as the practical range is about 80% of the EPA range representing charge cycles between 10% and 90% of capacity. If most of your driving involves less than 200 miles per day the 250 mi range model may be acceptable if you are willing to make charging stops on your 200 mile trips. I think the best advice is to put the trips you expect to make into A Better Route Planner (they don't have the CT models in there yet but I'd guess they will soon) and see what you are likely to experience.

One thing to think about WRT battery size is that a trailer consumes watt hours in addition to those consumed by the truck itself. If you plan to tow at all get the biggest battery you can afford.

 

[Larry Johnson]

My model 3 charges around 44 MPH per hour at home. So that means I'll have to charge more than 10 hours for the 500+ range model.

May I ask which charger you have?

 

[ajdelange]

As of today ABRP has the Cybertruck models as options for route planning. They have the tri motor using 485 wH/mi. That implies battery size substantially bigger than 200 kWh.

 

[Rootinboy]

I have the ability to charge at 80 amps .. about 60 miles and hour .. and never, ever, use it at that power level. 30-40 is fine and I drive 50,000 km a year.

Asking a clarifying question. You drive a Tesla 50k miles/yr!? I'm very interested as I'm buying the tri-motor and expected to drive 50-70k/yr.

 

[Rootinboy]

Asking a clarifying question. You drive a Tesla 50k miles/yr!? I'm very interested as I'm buying the tri-motor and expected to drive 50-70k/yr.

Noticed km. Roughly 30k miles. But still...