Ranges, batteries and charging

Ranges, batteries and charging

Having been raised with the Metric system I tend to think in km rather than miles. So the ranges of the batteries Tesla has discussed are:
160 Mi = 257.5km

So the two longest trips I make on a regular basis are weekend trips to the family cottage (about 360km each way) and a couple times per year I drive between Toronto, ON and Charlotte, NC (~1250km).

Clearly the longer trip requires ICE, train or plane. Doing it in an electric car would still be workable, but I can't tackle it in one day (like I do now with my TDI).

According to I should be able to get ~170Wh/km at ~100km/h (35km/h should be about 87Wh/km).

What I am concerned with is the viability of the cottage trip. A Roadster can't make it without charging (53kwh / 170Wh = 311.7km if you go full to drained which is bad for the battery). If we assume for a moment that the heavier, but more aerodynamic, Model S will have the same energy consumption as the Roadster (based on statements I have seen from Tesla and taken quite literally here) the max ranges on the highway (100-105km/h) would be:

The numbers above don't take into account the small annual loss of capacity that occurs.

My parents live about 1/3 of the way from Toronto to the cottage. I haven't asked yet, but I assume I could add a charger in their garage (as long as I pay for it). How viable would it be to:
-pack and charge the car before I leave for work on Friday
-drive 30km to work
-after work drive to my parents' house (about 125km from work) to top up the charge and make (or order) dinner. How long would this charge need to be? I need to leave their garage with 240km of highway speed range (min 83% on the mid-size battery and 63% on the largest)
-finish the drive and then plug into an ext. cord at the cottage to spend the weekend charging.
-On Sunday night I would also stop at my parent's house to recharge for a bit before continuing on.

I make this trip about 15 times per summer (average 4 long weekends and 11 regular weekends). Rental cars would add up to about $2350 per year (assumes HST (Harmonized Sales Tax), a frequent renter discount and 60L of gasoline at $1.15/liter).

Regardless of the selected battery pack I might want to look into the viability of getting a real charger for the cottage. Without one I would be running a 30m (100') ext cord back to the building to grab standard 120V/15A power. Charging that way would be Very slow.

By the time I take delivery of my Model S my TDI will be 13 years old. Maybe this is incentive to keep it on the road until the annual repair costs get out of hand. However, I have no interest in owning 2 cars.

Discoducky | January 30, 2011

Get the 230 battery, save the TDI for the first summer just in case, stop at your parents for an hour and buy a 240V charger for them (maybe they'll get a Model S and have need for it anyway?) and leave the car charging all weekend at the cottage since I assume you'll be fishing and hiking ;) Cheers!

AlfredG | January 31, 2011

Range depends a lot on the road, speeds and your driving habits. With the Roadster I get regularly 150-160 Wh/km on a trip with a bit more than half of it on motorways at 100-120km/h and the rest on local roads at speeds of 50-80 km/h with no effort to stretch range. So just holding your maximum speed back to 100 km/h would be sufficient for some additional reserves.

If your Model S is equipped with a 480 km battery, you can assume that you will have that range at those same moderate speeds (same test cycle base). So you should have no problems to drive those 360 km.
- Alfred

dsm363 | January 31, 2011

Yeah. I'd opt for the 300 mile pack. You take this long trip often enough that it'd be worth it. You could probably make the trip in range mode without recharging. Are you assuming you'd charge only in standard mode for these trips?

I'd wait of course until the Model S specs are finalized before you spend any money at your parent's place in terms of chargers/upgrading wiring too but probably a 50A circuit would add about 30 miles of range an hour. Stopping by there for 2 hours for a visit should get you there with a 230 mile pack. If you were to install whatever the Model S equivalent of the Tesla HPC 70A charger at your parent's house, you could stop even less time.

dsm363 | January 31, 2011

You'd definitely want a better charger at your cottage too. Even something as small as a 30A dryer outlet would be much more useful than a regular outlet.

Roadgen | January 31, 2011

I plan to purchase an S model next year. I am hoping that they will develope a wireless (See Powermat for iPhones) charging system for the car. Induction seems to be a very efficient way to deliver power and you can't drive away with the cord still plugged into the car. (Unless the car won't drive with the car still plugged in.)

jkirkebo | January 31, 2011

Actually, induction is a very _in_efficient way to deliver power, the losses are an order of magnitude more than via cable.

If the charge door is open, the Tesla will not move.

Ramon123 | January 31, 2011

At 240V/50A, the charging rate (from the wall)
is 240X50=12000, or 12 kilowatts per hour, or roughly
fifty or so miles of range per hour, depending upon actual range and how much of that juice is actually captured by the battery pack (probably between 85 and 90 percent).
It may be true that the 300 mile battery pack will allow a recharge as fast as the 230 roadster pack. MIT recently
demonstrated that speed of recharge has no effect on a battery's lifespan. They also came up with a faster method for recharging.
I assume they are recharging with massive parallelism.