I was reading the LA to Vegas thread and it got me thinking about a possible Phoenix to Vegas drive in the MSP. It would be almost impossible to go the full distance from PHX to Vegas on one charge because of the distance and because of the elevation changes. Its 281 miles. There are multiple changes between 1100 and 3500 feet from a -2% to +4% grade. Anyone care to speculate the correlation of the range loss due to elevation change? Possibly a simple ratio. Here is a leaf owner posting: Re: [EVDL] Help: What's the Leaf EV range reduction with mountainous driving? - DIY Electric Car Forums There are some good tools that cyclists use to keep track of elevation changes. This is one Bike Maps, Cycling Workout, Biking Routes | MapMyRIDE

Good question. When I had calculus in high school I could probably have solved that for various % grades, feet of elevation changes, mass of car, etc. Now, not my bailiwick. Any mathematicians out there want to calculate? Perhaps this kind of stuff would make a great range app (add in wind speed, temperature, etc.) that would make onboard computer even more precise.

Based on my brief experience with the Roadster, elevations mean bupkus. The regen is so strong that elevations just don't seem to matter that much. Bet the Walmart in Kingman will have at least a 120 volt outlet for you in their lot. Or try Chloride, even. Bet you can make it to Vegas in good time. --

just remember that it do not need air to drive, so the higher the altitude is the thiner the air is, and the less wind resistance there will be only problem the driver need the air to breath

I had posted this on another thread - Range and cost calculator. Not sure how acurate it is but cool to play with. Perhaps some Roadster owners can chime in with their real life experiences with regards to range and road topography changes.

Someone a while back posted this site: http://www.jurassictest.ch/GR/ It is the best range predictor that I have seen that take elevation into account.

260 miles from PHX to HOOVER DAM. What could be cooler than to recharge at Hoover Dam?? Turn it into a photo op & post pix here!! --

My experience driving the RAV4-EV is that climbing a hill definitely uses significantly more power, but if you're able to coast down the other side, it pretty much makes up for the difference.

Assuming a gross weight of about 5,000 lbs it will take about 1.9 kWh of energy to climb 1,000 ft. (2267 kg * 305 meters * 9.81 Joules / 3,600,000 J = 1.9 kWh) At freeway speeds, you'll get nearly all of your energy back going back down any hills - you only lose energy if you end up having to use regen to maintain speed since regen is not 100% efficient. So perhaps round up to 2 kWh / 1,000 ft and assume 3 mi / kWh. Phoenix to Las Vegas is 287 miles (96 kWh) and a net elevation gain of ~1,000 ft (2 kWh). So energy use due to elevation gain is pretty negligible in this case, but you'll have to slow down to make it from Phoenix to Las Vegas on a single charge. I'd guess limiting speeds to 60 mph should get you there - depending on AC use you may need to slow down a bit more!

I can confirm similar experience with my LEAF. I live in Santa Cruz and frequently climb over highway 17 to Silicon Valley. While the climb certainly uses more energy than the flats, this is cancelled out by not needing *any* on the way down plus of course reclaiming some through regen. You definitely take a bigger hit from air resistance, even just 65-70 mph vs. 55-60 mph is a bigger deal than climbing. Of course you do need to really believe this as you're climbing up and watching your range estimate drop off quickly. ;-) From experience in my LEAF, I like to have at least three "bars" of charge showing or about 25% to get back over the hill on the way home. Which is also why the charge stations should be at the bottom of such climbs, not the top. (Yes, there has actually been talk of a DC charger going in at the top of 17 and I've been hoping to discourage that – put it down in Los Gatos instead!)

Indeed. The first time I climbed 17 in the RAV I was definitely keeping an eagle eye on the SOC indicator. But, from the summit, I think I essentially coasted all the way to Santa Cruz with a bit of regen on the steep sections. Got to my destination there with essentially exactly the same SOC I had at the top of the hill.

I've been thinking about this issue a lot lately because the most common trip that I take that would push the range of an 85kwh battery is to go from the Bay Area (Marin) to Tahoe. The trip is 200 miles with an elevation gain of 6000 feet. Add to that fact that you'd either be going in the winter through quite cold temps or in the summer going through the central valley with temps near 100F, so AC or heating would be very desirable. I really hope the S can do this trip AND I really hope that they put a supercharger or two along the route. The Bay Area is such a huge market for Tesla and this trip to Tahoe is so important for many in that market. Even more so when the X comes out - critical it can do the trip for many in this area.

Steph/Rob, I'm with you on this. Tahoe would be the furthest I'd drive my (now 85 kWh-equipped) S. I think a supercharger somewhere near Sacramento or further up near Loomis/Auburn/Colfax may make sense as one heads into the mountains on I-80. Reno, on the other side, will surely offer charging options. Of course, we can always bank on Bonnie to let us freeload for a top up when we get to Sac both ways :biggrin: