A close call with running out of battery power driving home

Here is a cautionary tale. Bottom line: Don't be dumb like us. Use the Supercharger network!

My wife decided to take a spontaneous trip, with our usual charge of 80% (indicated 268 mi range. The town was 110 miles away, so no big deal, right? Well, after interstate speeds and low temperatures, the return trip range was too low. Two options: (a) drive 45 minutes in the other direction to the Supercharger, then 2 hours home, or (b) get some juice from a hotel destination charger, have dinner, and drive 1.5 hours home.

She chose (b) - mistake 1. Charging took 3 hours and got her to 150 miles range. 40 miles buffer, no sweat. She plugged in the navigation, and it said go to the supercharger. Nah, we got enough to get home - mistake 2. Tesla said to keep it below 65 to make it home.

Long story short, the Tesla range kept going down faster than linear. I assume it was because of the cold (29° F). I was watching the range on my app from home, and it looked terrifying - it looked like she was not going to make it. She tried stopping at an Electrify America station just off the interstate, but it was CCS and CHAdeMO only. She kept it to 65 mph, then 60, then down to 55 as the range got closer to zero. Several miles from home, range finally indicated zero. I had driven our ICE car out of town several miles to follow her in case the car shut down.

She made it home, with the range on zero miles for several miles. Apparently there is some kind of reserve, but I don't want to ever ever find out how much that reserve is!

Lesson: Use the Supercharger network, even if it's out of the way. It might save time and keep you from losing years of your life to range anxiety.

 

[GtiMart]

What about the Tesla to CCS adapter? Isn’t that included with each Tesla? (I’m not an owner yet, waiting on delivery).

A Tesla to J1772 is included to charge on level 2 (AC) chargers, there is no DC fast charging adapter included. The mobile charger is also included to charge on 120/240V AC with a 5-15 plug provided and others bought separately

 

[gagirl65]

A Tesla to J1772 is included to charge on level 2 (AC) chargers, there is no DC fast charging adapter included. The mobile charger is also included to charge on 120/240V AC with a 5-15 plug provided and others bought separately

That’s good to know. Thank you.

 

[Tman317]

While I love driving my MYLR when charging on trips starts to become too much of the trip I switch to my ICE VEHICLE.. NO STRESS!

 

[boulder.dude]

While I love driving my MYLR when charging on trips starts to become too much of the trip I switch to my ICE VEHICLE.. NO STRESS!

Let us know how we can help here. Yesterday, we drove 850 miles from Denver to Phoenix and it was great. It definitely requires a higher level of planning and awareness then driving an ICE, though.

 

[Dennisis]

While I love driving my MYLR when charging on trips starts to become too much of the trip I switch to my ICE VEHICLE.. NO STRESS!

If you're stressing on trips with your MY you're just not doing it right, shouldn't be stressful at all.

 

[SecondFiddle]

I had a 187 mile leg that the estimator suggested I'd have 18% left after. I drove mostly 71mph (per gps). During the first half of the drive, the estimate of range at completion was dropping by about 1% per 10 miles, so it looked like it would end with about 10%. However, the decline sped-up in the 2nd half, and it ended-up at about 3% with 5 miles left. Then it dropped to 0% in just 2.5 miles (despite my dropping speed about 15mph). The car did finish the leg, but I would say to be prepared for that last 5% to be less than expected. It's possible that my BMS is still building a profile of its battery, since it's only 3 weeks old. I reran the route today in ABRP using yesterday's wind and speed, and it's guessing 13% left, so there may have been some other factors. Heat was set to 64F with "blue" defog (not red), so... not going crazy with the heat.

 

[SecondFiddle]

I had a 187 mile leg that the estimator suggested I'd have 18% left after. I drove mostly 71mph (per gps). During the first half of the drive, the estimate of range at completion was dropping by about 1% per 10 miles, so it looked like it would end with about 10%. However, the decline sped-up in the 2nd half, and it ended-up at about 3% with 5 miles left. Then it dropped to 0% in just 2.5 miles (despite my dropping speed about 15mph). The car did finish the leg, but I would say to be prepared for that last 5% to be less than expected. It's possible that my BMS is still building a profile of its battery, since it's only 3 weeks old. I reran the route today in ABRP using yesterday's wind and speed, and it's guessing 13% left, so there may have been some other factors. Heat was set to 64F with "blue" defog (not red), so... not going crazy with the heat.

sorry, meant 1% drop in estimate per 20 miles drop (can't edit yet). It was looking like use would end-up matching ABRP, but ended-up doing a bit worse.

 

[GtiMart]

Did you use all the advanced configuration settings in ABRP? Reference and maximum speed you intend to drive, additional weight in the vehicle, temperature, road condition (wet or dry etc)?

 

[Rocky_H]

I had a 187 mile leg that the estimator suggested I'd have 18% left after. I drove mostly 71mph (per gps). During the first half of the drive, the estimate of range at completion was dropping by about 1% per 10 miles, so it looked like it would end with about 10%. However, the decline sped-up in the 2nd half, and it ended-up at about 3% with 5 miles left. Then it dropped to 0% in just 2.5 miles (despite my dropping speed about 15mph).

For those of you reading this and being terrified, I don't blame you, but you don't have to let this happen. 187 miles is about two and a half hours of driving. There is plenty of time to adjust this early on in the drive. And you don't have to keep your cruise control set at 71 mph and just watch in helpless fear as your remaining margin dwindles and goes away.

You can touch your speed down by a couple of miles per hour. It will re-estimate that projection over the rest of the drive, and then update the arrival estimate over the next minute or two. If it's still dropping, you can try lowering another couple of mph. Find a place where it steadies out and stops dropping. So I will generally try to keep that remaining estimate above 10%, because I don't ever want to be "That Guy (TM)", who gave the EV movement a black eye by risking and cutting it too close and running out of battery and having to call a tow truck and causing gas car drivers to point and laugh at the electric car, reinforcing their negative stereotypes and giving them bad stories to tell their friends. Don't be That Guy.

 

[SecondFiddle]

it ended-up at about 3% with 5 miles left. Then it dropped to 0% in just 2.5 miles (

I’ve noticed a glitch: while driving, I usually ”swipe up” on the turn-by-turn, to watch the estimate of battery on arival, to notice if it goes up or down. I don’t really watch the SOC% much, because SOC at the end of the drive is the important Thing.

But on that previous trip, when it was estimating that I’d have 3% at completion (OK) with 5 miles to go, I glanced up at “current SOC%” and that also read 3% (not OK).

I noticed this glitch again: Here I have 19% SOC and 5.4 miles to go, but Trip Planner is estimating that I’ll magically still arrive with 19%

 

[davewill]

I’ve noticed a glitch: while driving, I usually ”swipe up” on the turn-by-turn, to watch the estimate of battery on arival, to notice if it goes up or down. I don’t really watch the SOC% much, because SOC at the end of the drive is the important Thing.

But on that previous trip, when it was estimating that I’d have 3% at completion (OK) with 5 miles to go, I glanced up at “current SOC%” and that also read 3% (not OK).

I noticed this glitch again: Here I have 19% SOC and 5.4 miles to go, but Trip Planner is estimating that I’ll magically still arrive with 19%

Not sure why you assume that's a bug. I'd think it possible to travel 5 miles without having the percentage move by an entire percent, especially if the end of the route is at low speeds like 30 mph and you have a long range battery.

 

[davewill]

Not sure why you assume that's a bug. I'd think it possible to travel 5 miles without having the percentage move by an entire percent, especially if the end of the route is at low speeds like 30 mph and you have a long range battery.

It can even go up if the end of route is downhill...

 

[SecondFiddle]

Not sure why you assume that's a bug. I'd think it possible to travel 5 miles without having the percentage move by an entire percent, especially if the end of the route is at low speeds like 30 mph and you have a long range battery.

Good point. In this case, the remaining 5.4 miles was mostly the 4.8 miles from I-29 Exit 45 / Love’s Travel Stop Menomonie WI to the Menomonie WI SuperCharger. All but the last 0.6 miles is posted 70mph. ABRP estimates that the 4.8 mile portion from Love’s to the SC should take 3% of SOC if driving at the speed limit. The preceding 0.6 miles @70mph would add another 0.25%.

So, we have 4.8 miles of flat 70mph freeway projected to use 0% of the pack.

 

[Bigship]

I like the paradigm: Never wait to charge an EV when you have to, charge when you can!