Monitored estimated charge at each stop

[BeesKnees]

Greetings,

Took a 500 mile journey in my 2 mo. old S90D. I monitored my energy use and compared it with the nav system estimates of expected use at each supercharger stop. That is, if the nav system said 20% should be left at Mumble City, I noted it against the actual used when I got there.

I must say it’s a little goofy to have the mixed up units. % for the estimates, and miles left in battery for actual. Oh well. I used the max charge miles at the beginning of the trip (294 miles showing in battery) as my 100% level. So 20% estimated would mean 20% of 294 miles, or 59 miles left as the estimate.

Below are the results for each supercharger stop and the final destination. Miles traveled for each leg, estimated % from nav converted to miles as described above, actual miles left in battery at each next stop. So the first row below reads as “traveled 150 miles with estimated miles left as 115, actually got there with 116 miles still in the tank.”

150, 115, 116 – wow, right on. Weird.

134, 100, 110 – beat the estimate with careful / slower driving

89, 88, 66 – missed huge, even with short distance traveled, really big hill climb for miles. Noted whr/m as almost 800 at times.

116, 100, 79 – wanted to get there, pumped speed up to 80, payed for it. Worth it.

There is NOT a cumulative effect. The estimate to each next stop changes after charging based on amount of charge taken. I used each new estimate as I went. So each row is independent of the last row. This allowed the charge times to be whatever and irrelevant to my experiment. I did not try to charge for the time it recommended. Lunch, walk about, etc.

Mostly freeway AP2 autopilot. Very fun. 65 - 70, mph for 1st legs. 80 for last.

YMMV. Ha. I've never used that phrase and meant it literally before.

Cheers.

 

[Rocky_H]

Huh--interesting stuff.

I must say it’s a little goofy to have the mixed up units. % for the estimates, and miles left in battery for actual.

You can change that setting for the display by the way, so you don't have to try to convert it. In Controls -> Settings, there is a setting for displaying as either "distance" or "energy". The names are a little weird, but if you change that to energy, it will show your battery meter display in %, rather than rated miles.

 

[BeesKnees]

Nice. Thanks.

 

[Lasttoy]

I picked up my car last Thursday in atlanta, drove toward DC. It said at each stop it only needed 20 to 30 minutes charge to get next stop. When it charged to that point, it said I could continue, that is insane, it said I would arrive with only 10% left. What if I hit morning traffic and sit there for 30 minutes? Newbies like me, be very careful, I sat in traffic in atlanta for 2 hours, if had not had full charge I would have been dead on the side of the road. Calculating all this can be challenging.
Going from DC to florida Monday, the system got lost. Sent me toward atlanta. I called HQ in calf, rebooted, everything, had to back track to Richmond and return charge, tried again. Worked ok rest of the way.

 

[BeesKnees]

Apparently running the charge at the low end of the battery is faster for the charge cycles. But yes, learning consumption rates and planning with them is a new fun thing. So far I notice that stop and go traffic doesn't seem to effect my range much. Needs more study...

 

[gregd]

What if I hit morning traffic and sit there for 30 minutes? Newbies like me, be very careful, I sat in traffic in atlanta for 2 hours, if had not had full charge I would have been dead on the side of the road.

Possibly not, unless you had the heat and/or air conditioning running, and even then, possibly not as bad as you think. Teslas (all cars in general, but EVs in particular) get much better range at lower speeds, so sitting in traffic can actually help. I took my Roadster to my brother's for Easter, and got stuck in traffic for over an hour, stretching a 2.5 hour trip to nearly 4. Arrived with more charge than expected, not less, due to the delay. Now, if I had the heat blasting during that time, it would have had an impact. Instead, I ran the seat warmers; they're nearly free.

It certainly makes sense to have a good cushion for the unexpected, as you did. 10% SoC margin would make me nervous, but you don't need to go overboard. Over time, with experience, you will learn how much to hold in reserve, just as you presumably have learned to do with a gas car. The most annoying part of the trip was ignoring the incessant offers from both the in-car NAV and Google Maps to pick a better (significantly longer) route in order to save "x" minutes. I had the time budgeted (it was a holiday), so relaxed, smiled, and enjoyed a bit of music.

 

[Rocky_H]

When it charged to that point, it said I could continue, that is insane, it said I would arrive with only 10% left.

Let me share a little from a long-timer. I have had my Model S for 3 years. From long before that "Beta trip planner" software, there was no "ready to go" notification, and you just figured out your own buffer % from what you felt comfortable with. The trip planner is still not too good with that. I always try to have 20% unless it's a route I've driven before and know fairly well, and then I'll go with 15%.

I took my Roadster to my brother's for Easter, and got stuck in traffic for over an hour, stretching a 2.5 hour trip to nearly 4. Arrived with more charge than expected, not less, due to the delay.

Yes, to Obi-Wan do you listen! Unless you're blasting a lot of heat, sitting stuck in traffic isn't bad in an electric car.

 

[brkaus]

50 miles of 15-55mph variable speed on interstate due to traffic. Used 10% less than planner said I would use.

My Cummings diesel would have been the opposite.