Range Failure

[gnuarm]

He said it told him to turn around. If that means it was directing him past or away from the supercharger and changed its mind, then it would be even more of a failure. However, multiple trips have been discussed, some of which involve taking an alternative route, so I'm not going to re-read all 5 threads to confirm whether or not that is possibly what happened.

@gnuarm as I typed the above, I thought of a logical explanation that could apply. If you did choose an alternate route and expected it to tell you to turn around for a short period of time before rerouting you the way you intended to go, is it possible that the 12% estimate you saw was for that supercharger and not your final destination? I know you say you turned the charging recommendations off to see charge at destination, but I assume you must have turned them back on in order to be told to turn around to charge. In that scenario, as you continued to get further from it, the estimate would drop quickly, because for each mile further you went, another mile would be required to get back. This doesn't necessarily make sense given your other experiences on this same route, but is it possible some atypical estimated range loss occurred on the highway and the route changed before you ever got to the surface roads or the navigation didn't reroute and you were still seeing an estimation to the supercharger vs your final destination?

All of this happened AFTER I passed the last Supercharger on the highway. The 12% estimate was for traveling to my ultimate destination which was some 10 miles past the Supercharger. The 12% estimate to reach my destination persisted until and all changes to my destination were after I left the highway and drove on the back roads.

I can't say anything about what the car would have recommended as I passed the two Superchargers on Rt 95 because I had told it to not recommend charging options in order to see the estimate at my destination.

I started this thread to let others know of my experience and to see if anyone could explain what happened to the range estimate. Most of the "suggestions" have been of the nature of "don't" try to drive the car without stopping at every charger, etc. Prior to this when I complained about the poor and inconsistent results using the other information available in the car the recommendations I received had been to trust the trip planner and rely on that remaining charge estimate. One fellow swore by the fact that his daily commute would get him home with 1% because that's what the trip planner said he would have. Of course I ignored the idea of shaving things that close.

Seems you can get any advice you want from this group. Lots of criticism available too. Oh well. Forget about it Jake, it's the Internet.

 

[juliusa]

You don't seem to understand his concerns.

His concern is that he did not have enough charge to reach his destination, after starting his trip prior to Trip Planner saying he had enough charge, and it is a "range failure". What am I missing?

 

[juliusa]

I started this thread to let others know of my experience and to see if anyone could explain what happened to the range estimate. Most of the "suggestions" have been of the nature of "don't" try to drive the car without stopping at every charger, etc.

What happened is you decided you had enough charge to reach your destination, and your calculation was wrong.

 

[juliusa]

You are ~65miles from destination. Car tells you you will get there with 12% remaining. There are no known reasons why the consumption would be higher than estimated. Yet you don't reach your destination. Explain this.

I'm not sure he has said that. If that is what he said happened, my explanation would be he "mis-remembered". If that happened, then I'd like to know at what distance from his destination the car reported less than 0% remaining?

Not very forthcoming with answers to questions. Indicates he may be mis-remembering or just not sure of what happened exactly.

 

[acoste]

I'm not sure he has said that. If that is what he said happened, my explanation would be he "mis-remembered". If that happened, then I'd like to know at what distance from his destination the car reported less than 0% remaining?

Not very forthcoming with answers to questions. Indicates he may be mis-remembering or just not sure of what happened exactly.

He explained everything in the very first post:

I left the last Supercharger with my destination set and the remaining charge at my destination at 5%. As often happens that number rose as I drove until it was about 11%, so I thought I didn't need to stop at any more until the one near my destination. Typically secondary roads with lower speed limits yield lower consumption numbers and the last 65 miles of this trip would be on secondary roads. However on leaving the highway, the projected final State of Charge (SoC) dropped and dropped until I still had some 35 miles to go and the projection dropped below zero!

 

[juliusa]

So you believe he said:

65 miles to go and showed 12% range remaining at destination (about 35 miles).
35 miles to go and it showed 0% remaining at destination.

So in driving 30 miles, it unexplainedly used 35 miles more of rated range than expected?

I think either you or he are mistaken.

 

[acoste]

So you believe he said:

65 miles to go and showed 12% range remaining at destination (about 35 miles).
35 miles to go and it showed 0% remaining at destination.

So in driving 30 miles, it unexplainedly used 35 miles more of rated range than expected?

I think either you or he are mistaken.

Looks like it was around 11%.

I have already described a scenario how this was possible. I don't know how the BMS is programmed, so I can't be sure. But I know how the total battery capacity is estimated and based on that it is a possible scenario.

 

[juliusa]

it is a possible scenario.

Anything is possible. Interesting how all these crazy things happen to the same few people, and nobody else.

 

[David99]

I left the last Supercharger with my destination set and the remaining charge at my destination at 5%.

There is the problem. See here: Don't leave unless it shows 6% or more arrival

 

[acoste]

There is the problem. See here: Don't leave unless it shows 6% or more arrival

That's useful information.

His case is a little different though.

There were two chargers along the route and I passed each of them with 12% showing as the expected remaining charge.

 

[David99]

That's useful information.

His case is a little different though.

I believe the problem has two layers. The first problem was leaving with 5%. That means he didn't have energy to make it to his destination from the start. The second problem showed up when, for some reason, the energy graph predicted 12%. I'm a little surprised this would happen because leaving with 5% means the car already assumes a slower driving speed. There is little potential to driven even more efficient to make the prediction go up so much.

 

[acoste]

I believe the problem has two layers. The first problem was leaving with 5%. That means he didn't have energy to make it to his destination from the start. The second problem showed up when, for some reason, the energy graph predicted 12%. I'm a little surprised this would happen because leaving with 5% means the car already assumes a slower driving speed. There is little potential to driven even more efficient to make the prediction go up so much.

" As often happens that number rose as I drove until it was about 11%"

I was wondering why this increase keeps happening to him. Maybe software related or maybe he really uses less energy than estimated. Maybe the battery temperature increases, and so offering more available capacity.

He said it was in range mode. But I don't know when he turned that on. Range mode heats up the battery.

 

[David99]

" As often happens that number rose as I drove until it was about 11%"

I was wondering why this increase keeps happening to him. Maybe software related or maybe he really uses less energy than estimated. Maybe the battery temperature increases, and so offering more available capacity.

He said it was in range mode. But I don't know when he turned that on. Range mode heats up the battery.

Yes Range mode warms up the battery but if had been on a Supercharger before the battery was definitely warm enough when he started.

 

[acoste]

Yes Range mode warms up the battery but if had been on a Supercharger before the battery was definitely warm enough when he started.

I mean range mode keeps the battery at around 110 deg F during the trip. At the charger the range estimator may use non-range mode battery temperature. Like 90 deg F.

 

[David99]

I mean range mode keeps the battery at around 110 deg F during the trip. At the charger the range estimator may use non-range mode battery temperature. Like 90 deg F.

The OP said he charged at a supercharger before he started driving. After a supercharging session, the battery is usually at 40-45 C / 105 -114 F. Range Mode on/off changes my range display in the car by 1-2 miles. Unlikely Range Mode can explain the difference between 5% and 12%. I don't know what was the cause. There are already 120 messaged speculating. I'll refrain from adding more

 

[acoste]

The OP said he charged at a supercharger before he started driving. After a supercharging session, the battery is usually at 40-45 C / 105 -114 F. Range Mode on/off changes my range display in the car by 1-2 miles. Unlikely Range Mode can explain the difference between 5% and 12%. I don't know what was the cause. There are already 120 messaged speculating. I'll refrain from adding more

Based on these curves you are right about the 1-2 miles. (25C to 40C looks like 1%, that is 3 miles)

Edit: ops, I checked the curve at 2.5V. But I don't think the car would let it lower than 2.8V. Possibly 3V. At those voltages the difference is a bit larger. 3-5%?

 

[gnuarm]

There is the problem. See here: Don't leave unless it shows 6% or more arrival

Why should I have not left? There were two charging stations well within range with high numbers for remaining charge on reaching them. So I should never drive further south than Rocky Mount, NC???

How much of my original description of the trip did you read?

 

[gnuarm]

Anything is possible. Interesting how all these crazy things happen to the same few people, and nobody else.

Yes, interesting how the same few people fail to read so many posts.

 

[juliusa]

It is a good idea to do one of the following when driving an electric car:
1. Keep charging until you have enough to reach your destination
2. Stop at a charger along the way

 

[David99]

Why should I have not left? There were two charging stations well within range with high numbers for remaining charge on reaching them. So I should never drive further south than Rocky Mount, NC???

How much of my original description of the trip did you read?

I'm not saying you did anything wrong. I'm just pointing out a behavior in the navigation that can fool owners and cause serious range issues later. I think Tesla should change the behavior when charging on a trip to always assume normal driving speed.