My wife and I have been hiking up at Mt Charleston weekly to avoid the heat down in the Vegas valley. The climb is 5700' to the trails above. I was not paying much attention to the battery, but my wife noticed last week that the battery % was actually increasing on the drive back down the mountain. That surprised the heck out of me! I knew the regen braking would add some charge back into the battery but never expected that just driving down the mountain would do the same! I am use to driving an ICE car up the mountain and using the brakes most of the way back down. It is so nice to not need to ride the brakes going down the mountain. Anyway, I did a short video yesterday to demonstrate the results of our ride up/down the mountain and to show the battery % change. I was also surprised at the huge demand in power going up the mountain, nearly 3 times the normal wh/mile going up. This is kinda useful to know for anyone planning a trip up a mountain to avoid running the battery down too low or possibly even to 0%.
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Model Y Regen Braking and Charging up/down a Mountain
- Thread starter Curious Nomad
- Start date
Here is an interesting rule of thumb -- every 500ft of elevation is about 1% battery capacity in gravitational potential energy alone (not counting friction, engine efficiency or anything else).
It's not a bad thing to keep in mind -- if you know you'll be driving up 5000 ft, you'll use about 10% of your battery capacity compared to flat ground. The flip side is that you'll gain it back when driving downhill, though there will be some losses (I remember reading that you'll get about 75% of it back).
It's not a bad thing to keep in mind -- if you know you'll be driving up 5000 ft, you'll use about 10% of your battery capacity compared to flat ground. The flip side is that you'll gain it back when driving downhill, though there will be some losses (I remember reading that you'll get about 75% of it back).
Do you know whether the Tesla navigation system accurately projects battery usage that takes into account substantial elevation gains ?
iamnid
Active Member
Yes. A way to tell this is to look at the Energy Usage graph for your trip. If it's particularly hilly, the graph will reflect it, including parts where the graph shows negative usage (downhill).
I know it the wrong forum, but just completed a 3k+ mile road trip through Colorado in an older loaner X and here is what I found:
The car was pretty darn accurate when it came to elevation / distance, but imprecise over longer distances. What I mean by that is I would undershoot/overshoot percentages by ~15% at rated speeds regardless of it being flat, up/down, mostly uphill, or mostly downhill. You can adjust consumption by reducing speed, but that doesn't affect the elevation change ENERGY HIT- so be careful if you plan on pushing it on a long uphill stretch, there is only so much optimization you can do. Ideally, you will have more than ~130 miles @~80mph on flat road, so it will not matter as much, but just something to keep in mind.
As an example, up Pikes peak, I was 4% under what the car estimated, and by the way down it was down to 2% difference in what the car would have expected, this was over 950+kw up, and -460kw down - 73%-31%-46%
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