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High Altitude Performance.

Hi,
I have one question. How good is the performance of the battery pack and the Tesla cars in Highlands (over 3500 mts (11,482 feet))
We have a lot of cities in my country that are above 3,500 mts. Like Cuzco or Puno. Also some pass through the mountains that are above 4,500 mts (14,763 feet)

If I travel in my ICE I know that I will lose at least 10 to 15% of performance due to less oxygen in the atmosphere. I know that oxygen doesn't affect batteries but what about altitude and temperature?

For example I had an Gen II Ipod and it doesn't work over 3,500 meters but I'm not sure if it was due to the battery or the hard disk

Grazie

Roberto

Do you mean the the iPod doesn't even power on, or that it can't get a signal? It does work again when it gets down to lower altitudes, doesn't it?

Teslas perform much better than combustion engines at altitude. Not only don't they require oxygen, reduced air resistance actually benefits their performance.

Early mobile hard drives failed at altitude even in an airplanes due to the lower pressure... the read/write head needs the air to fly correctly. Modern hard drives can tolerate air pressure variations.
Electric cars have no air pressure dependent parts in the drive train, so you should experience no performance degradation. Batteries have pressure relief.

Thanks guys,

David70, Yes, the ipod didn´t work, I don´t remember but i thing it didn´t turn on. When I return to lower altitud it work normal again.

RVillafuerte,

Well I couldn't connect to my car via iPhone last night, but there were no cell phone towers in the area, and I was at a much lower altitude than surrounding hills.

Temperature does affect batteries a bit though, so you might get some difference in performance depending of how cold/warm weather is. Not much for Tesla cars though, because battery is liquid-cooled and not air-cooled.

I don't know about driving up to Cusco, but heading back down to Lima you might get enough regen to completely recharge the battery.

Also, whereas the quality of petrol can vary considerably from station to station or country to country, you'd never have quality-control problems with a Tesla.

You can never "completely recharge" with regen, assuming you drove up on the same original charge. Some have reported 80-85% recovery, but there are always losses.

I drive six miles losing 1800 feet in the process. This is not precise, but driving a maximum of 45 mph and using no brakes, setting the trip meter at my house and at the bottom, I get usage of
minus 350. Going back up the same six miles, maximum 45 mph, no need for brakes, now climbing 1800 feet, I get usage of 885. So, I get about 40% back. This is from 7000 feet to 5200 feet. I have hit close to these numbers several times.

As for altitude itself, a group of Colorado Tesla owners drove up Mount Evans, 14,265' (4,348 m), with no noticeable change in performance of batteries or power.

@JaneW What was your SOC (or rated miles) when you started down?

Uphill-downhill is zero gain, zero lose game. You always get all the potential energy back. Usual losses apply to both directions, so net result is always negative. 40% gain to battery is very good considering losses.

I think most efficient downhill gain would be the case where you coast down with zero acceleration in either direction at your desired speed (no conversion losses going down).

"where you coast down with zero acceleration"
Wonderful ideal, but impractical. How do you coast with zero acceleration? With a 4500 lb. car on my hill, you would burn out your brakes, and you are wasting all that momentum. I am (essentially) coasting with zero acceleration by modulating the accelerator on the MS.

Rated miles at the top of the hill -241. 243 at the bottom.

Requires a small inclination so that air&rolling resistances equals gravity assisted downward vector of forces.

So optimal situation is obviously something most people don't have access to.


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