Road trip buffer

[Oba]

When posible, 20% or more. An unexpected head wind can really eat range.

8% is my goal, and here's why:

I charge to compensate for whatever conditions are on the next leg. So, a familiar route, nice weather, no known surprises, then the only consideration is how fast do I want to travel. But I'm shooting for 8%, since 7% is where the "drive slowly" warning comes up (when it pops up, it's a great wake up call that the speed needs my attention).

For 65mph, I'll charge until 10% shows at the next destination, and more for higher speeds (maybe 20% for 75-80mph).

Then, I monitor that value the whole way. You want to make corrections early, so for a 65mph drive starting out at 10% remaining at the destination (or next Supercharger), I want it to ultimately drop to 8%, however I'm comfortable if it stays at 10%. If it rises to 11-12%, then I speed up 5mph and remain at that speed until it either drops back to 10%, or increase another 5 mph if it keeps increasing.

The reverse is true, also. If I start at 65mph, then see the destination % drop down to 8-9%, I need to slow down and monitor. Maybe there is a surprise headwind, or low tire pressure? If it keeps dropping, I slow further; 55mph, or 50mph. Whatever it takes to stay above 7% remaining.

If I'm within "attack range" (maybe 10-20 miles from destination with known charging or next Supercharger) within an urban area (lots of options for electricity and tow trucks), I'll let it drop to 3-4% by driving faster.

 

[Barry]

Beats me why it works that way on my car. I will often see myself trending below the line within the first mile or two. And I do not tend to drive fast or aggressively, and it does show in my very good Wh/mi numbers.

Check your tire pressure?

 

[mknox]

Check your tire pressure?

Yep. Weekly. The thing is I am usually getting at or better than rated Wh/mi numbers, so the whole thing is puzzling. I figured if I got spot on Rated Wh/mi, I should be right on the line (give or take a bit).

 

[Max*]

Yep. Weekly. The thing is I am usually getting at or better than rated Wh/mi numbers, so the whole thing is puzzling. I figured if I got spot on Rated Wh/mi, I should be right on the line (give or take a bit).

And your Wh/mi numbers are much better than mine (Lifetime 307. Typical roadtrip driving at 70-75mph is about 280Wh/mi. The lowest I've seen was 260Wh/mi on a stretch with some slower moving traffic on it)

 

[mknox]

And your Wh/mi numbers are much better than mine (Lifetime 307. Typical roadtrip driving at 70-75mph is about 280Wh/mi. The lowest I've seen was 260Wh/mi on a stretch with some slower moving traffic on it)

I do tend to be a more "moderate" driver. My commute is mostly freeway with a speed limit of 100 km/h (62 MPH) and I usually drive between 65 and 70 MPH even though a lot of traffic is moving faster. It's been quite hot here with temps in the mid-90's and high humidity, so my a/c is working double time. Even so, I can see numbers around 265 Wh/mi on my approx. 45 mile commute home from work with the a/c blasting. Even lower if it's nice out and I don't need the a/c. In fact, my August number was 298 Wh/mi on a bit over 2,100 miles which includes more than just my commute. So it's puzzling that whenever I do use the Trip Planner, I always come in worse than the initial projection. I still have to wonder if the Trip Planner starts out with the assumption that I have a factory-fresh battery with no degradation, then when the "real" numbers start coming in, things go south.

 

[Oba]

I still have to wonder if the Trip Planner starts out with the assumption that I have a factory-fresh battery with no degradation, then when the "real" numbers start coming in, things go south.

Just to be clear, you're talking about the planning software in the car, not EV trip planner, correct (the internet site)?

 

[mknox]

Just to be clear, you're talking about the planning software in the car, not EV trip planner, correct (the internet site)?

Yes, sorry if that wasn't clear. I'm talking about the tab in the Energy App in the car that shows your projected and actual battery SOC over the duration of your trip.

 

[jerry33]

So it's puzzling that whenever I do use the Trip Planner, I always come in worse than the initial projection. I still have to wonder if the Trip Planner starts out with the assumption that I have a factory-fresh battery with no degradation, then when the "real" numbers start coming in, things go south.

That's interesting because I almost always come out ahead or even with the trip planner. It would be nice know exactly what it took into account.

 

[David99]

It actually depends on the situation. I know a few routes where from previous trips well so I can plan tighter, other times the weather requires more or if unknown I tend to give myself extra.

In general though, I used to plan and drive in a way that I arrive below 10% to minimize charge time. I don't do that any more as I learned it's not good for the battery. It's OK when going very moderate, but on road trips I tend to go faster and draw more power.