Driving in mountains (not through) in EV, when to charge?

[MontyFloyd]

Something that I am wondering about, driving in mountains (not through) in EV, when to charge?

With regen-braking energy goes to charge batteries, which means it is best to have storage capacity.
Logically the best thing to do is at base of mountains charge to 90+%, and no more than, say, 40% charge at top if at all.

Thoughts?

 

[RobDickinson]

Uh dont overthink it unless you charge at the top to 100% it wont make much difference

 

[garrett5688]

How big a mountain we talking here

 

[swaltner]

How big a mountain we talking here

This! The general rule of thump is that you recapture 5-6 miles of range descending 1,000’ in altitude.

Even if you descended from the top of Mt Everest to sea level (down a nice paved road not using mechanical brakes), you’d be hard pressed to add 50% charge to a battery on a “modern)” (250 mile or more range) EV.

 

[Earl]

Mountains are easy. If you're driving over them, they pretty consume the same energy as flatland. Your extra consumption on the way up is made up by coasting and regen on the way down.
If you're hard pressed to make it to the top, better charge before the climb. Charging at the top is pretty much a waste of time - certainly don't charge to more than about 60%. Most of the major grades I've encountered (I-5, I-80, and I-15 in CA as well as I-70 in CO) all have strategically well placed Superchargers at both ends, making them easy.

 

[MontyFloyd]

How big a mountain we talking here

Definition: " Most geologists classify a mountain as a landform that rises at least 1,000 feet (300 meters) or more above its surrounding area. "
Appalachians, Ozarks, and up., IOW,

This! The general rule of thump is that you recapture 5-6 miles of range descending 1,000’ in altitude.

THIS! Just what I am looking for.

Even if you descended from the top of Mt Everest to sea level (down a nice paved road not using mechanical brakes), you’d be hard pressed to add 50% charge to a battery on a “modern)” (250 mile or more range) EV.

So as long as I have no more than 80% charge at top of mountain, then I should have a plenty of capacity of regen on way down.

 

[MontyFloyd]

Uh dont overthink it unless you charge at the top to 100% it wont make much difference

That is exactly the point I was asking.
At top do not charge over a certain %, otherwise friction brakes will be needed on way down (or run all your accessories at full blast).

 

[Earl]

80% charge at top of mountain

Obviously, I'm over-thinking this but I would push this down below 80%, especially if this is a big mountain (not one of those 1000 ft hills .

While you will have regen at 80%, the heavy regen power you may be putting in will be easier on the battery at 20 - 60% than 80%. Just think of where your battery starts to taper in charging speed at a Supercharger. That's where you want to be descending. Strong regen starts to get into charging rates like supercharging (Although I don't believe it gets above ~40 kW).