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.

 

[Kandiru]

Why don't you have the J1772 adapter? It comes with the car...

In his defense, La Mujer was the pilot

 

[Gokada]

Too close for comfort for sure! I have a similar story. This morning I drove 90 minutes to work, distance is 96 mi. With my range showing 280 mi. I thought it would be plenty. Lo and behold by the time I got to work 60% of my battery had depleted. There are no Tesla compatible chargers in this small town (without a J1722 adapter) so I have to drive an hour and 20 minutes to a different small town to the Superchargers and then drive another 45 minutes to the Superchargers closer to home. And then rinse and repeat tomorrow. Hopefully my J1722 comes in soon. Currently plugged into a 110 socket at 4 miles per hour. That’ll get me about 48 miles over 12

Why don't you have the J1772 adapter? It comes with the car...

Bought it used. I looked in the charging cable bag, in the trunk, glove box, and the frunk to no avail. But I may have enough to get to the superchargers close to home.

Being plugged into a regular wall plug currently, looks like I’m only getting 1 mile per hour of charge even though the car says 4 miles per hour. When I plugged it in, the car had 118 miles left. If I’m plugged in for 12 hours then I should have 130 miles after my 12 hour shift is over (118+12).

This morning I had 40% left when I arrived to work. If 40% of 130 miles is 52 miles, I’ll have enough to get home. The superchargers are actually closer than my home so I’ll hit that up first. Also the temps should be around 50 degrees Fahrenheit. This morning was 18. Can anyone let me know if that sounds right? It would be much appreciated…

 

[Silicon Desert]

Between the cars temperature sensor, local weather data using GPS + internet, and just general time of year (its winter).. it could have saved you some trouble by giving you a reasonable range projection from the get-go.

It sounds like it did give them an idea of what was needed since it told them to stop at a supercharger at the start. At least my car does that. In the winter I come from Fremont CA to Sparks which is also 4,000 feet of elevation increase. In Sacramento, my MX tells me I need 190 miles of charge in the winter and 170 miles in the summer when the actual distance is only 145 miles.

 

[GtiMart]

If your battery is cold, plugged on a 120V 12A source you might see 0 miles per hour of charge, while the battery heats up (e.g. all available energy is used to heat). Once it heats enough you will get around 1.2kW to the battery for charging.

With an EV you should be prepared and have a plan B, a plan C etc. You should really get acquainted with apps like PlugShare to find all sorts of power sources around you. You should be setup to accept power from various sources depending on your situation. Superchargers and Tesla chargers are built-in. J1772 is an absolute must. 120V 12A (e.g. a normal wall plug) is a last resort because of speed.
When you leave for any "long" trip you should plan with something like ABetterRoutePlanner unless you know your area is very well garnished in superchargers. It's not the case here, planning is essential.
A CHAdeMO adapter is not essential but is nice to speed things up when superchargers are not present, but they don't sell it anymore. A CCS adapter will replace it eventually. As long as you have your J1772 adapter you shouldn't be stuck anywhere. It just might take a little while to charge.

The Tesla shop will sell you the J1772 adapter, it's relatively cheap.

 

[Gokada]

If your battery is cold, plugged on a 120V 12A source you might see 0 miles per hour of charge, while the battery heats up (e.g. all available energy is used to heat). Once it heats enough you will get around 1.2kW to the battery for charging.

With an EV you should be prepared and have a plan B, a plan C etc. You should really get acquainted with apps like PlugShare to find all sorts of power sources around you. You should be setup to accept power from various sources depending on your situation. Superchargers and Tesla chargers are built-in. J1772 is an absolute must. 120V 12A (e.g. a normal wall plug) is a last resort because of speed.
When you leave for any "long" trip you should plan with something like ABetterRoutePlanner unless you know your area is very well garnished in superchargers. It's not the case here, planning is essential.
A CHAdeMO adapter is not essential but is nice to speed things up when superchargers are not present, but they don't sell it anymore. A CCS adapter will replace it eventually. As long as you have your J1772 adapter you shouldn't be stuck anywhere. It just might take a little while to charge.

The Tesla shop will sell you the J1772 adapter, it's relatively cheap.

Thank you for the advice. I do have a plan B but not really a plan C. And you’re correct, I saw 0 miles per hour. Any idea how warm it has to be to start charging a little faster? Just ordered the J1722 last night. I wonder how many months for delivery.

 

[jcanoe]

Just ordered the J1722 last night.

Every new Tesla vehicle comes with the Tesla SAE J1772 adapter. Unless you need a second adapter there is no need to purchase this from the Tesla store.

 

[Gokada]

Every new Tesla vehicle comes with the Tesla SAE J1772 adapter. Unless you need a second adapter there is no need to purchase this from the Tesla store.

Yes, I bought used and didn’t find it after checking all the usual places.

 

[Gokada]

If your battery is cold, plugged on a 120V 12A source you might see 0 miles per hour of charge, while the battery heats up (e.g. all available energy is used to heat). Once it heats enough you will get around 1.2kW to the battery for charging.

With an EV you should be prepared and have a plan B, a plan C etc. You should really get acquainted with apps like PlugShare to find all sorts of power sources around you. You should be setup to accept power from various sources depending on your situation. Superchargers and Tesla chargers are built-in. J1772 is an absolute must. 120V 12A (e.g. a normal wall plug) is a last resort because of speed.
When you leave for any "long" trip you should plan with something like ABetterRoutePlanner unless you know your area is very well garnished in superchargers. It's not the case here, planning is essential.
A CHAdeMO adapter is not essential but is nice to speed things up when superchargers are not present, but they don't sell it anymore. A CCS adapter will replace it eventually. As long as you have your J1772 adapter you shouldn't be stuck anywhere. It just might take a little while to charge.

The Tesla shop will sell you the J1772 adapter, it's relatively cheap.

Ok I think I’m good. Just checked the car and it’s at 4 miles of charge per hour, 144 mile range and I still have 5.5 hours of charging left. That should get me about 166 miles of range after my shift is over. I really only needed 130. Definitely considering getting the Tesla wall charger installed.

 

[GtiMart]

The battery will not accept any charge at or under freezing for sure. You can see it clearly on your regen bar, you won't have any regen either at those temps. The actual temperature required depends on the power you want to push in the battery. Supercharging at maximum speed requires a higher temperature than level 2 charging. I'm under the impression that 120V 12A charging probably requires the same thing as level 2. I'm pretty sure this has changed over time in various software updates. Currently it's somewhere between 4 and 8 degrees C if I remember correctly. Don't quote me here, it's an approximation. It could be 10C... I'd need to check again with scanmytesla the next time I leave my car parked outside...
As far as heating the battery beforehand... driving the car will warm it slowly up to a point. Newer cars with heatpump scavenge some heat to warm the cabin, but even that has evolved with software udpates. I'd say just let it plugged and eventually it will charge.

 

[mmoran]

A couple of things here. Glad you made it home without calling the tow truck.

In the winter time set your charge limit to 90% instead of 80%. It will NOT hurt the battery.

When you are doing a road trip in winter you can always get up in the morning and bump the limit from 90% to 100% and get ready eat breakfast and leave when the car nears 100%. I would never charge to 100% every day but once in a great while, like your winter road trip here it will be fine.

Get used to using the Energy screen. It will give you and average kWh used and update the estimated range based on the last 30 miles. It really works and you can see the changes due to weather or speed. Test it out by comparing 60 MPH to 80 MPH the difference will be significant.

If this trip had been done on a nice spring day with mild temps you probably would have been fine. You have to be more careful in the winter.

Elon says going to 100% isn't any better than 95% because the regen brakes don't work. So the efficiency of the car is diminished losing the benefit of the 100% charge.

"It’s not a big deal. Charge to 90% to 95% & you’ll be fine. At 100% state of charge, regen braking doesn’t work, because the battery is full, so car is less energy efficient."

We've had some cold weather here in the the NE USA and you definitiely need to factor that in. In the same trip we take in the summer without charging , we're needing a definite boost charge.

 

[IamGaryGnu]

I just wish the percent remaining on arrival wasn't buried at the bottom of the navigation turn by turn list. Would like to see current and final at a glance. And in a way that doesn't modify the map orientation.

i was going to write this. i like to see my estimated percentage at my destination (and then it shows round trip) - i don't know why it can't simply show remaining estimated range all the time, like it does time, mileage, etc. on the map. should be uber simple to program, the data is there, just not displayed.

 

[Rocky_H]

At 100% state of charge, regen braking doesn’t work, because the battery is full, so car is less energy efficient."

I've always laughed at that statement. People say that as if doing that will cause you to not have regen all day, or for an hour or more. It's ridiculous. By the time you drive a few miles, it will have depleted some energy, and you will start having some regen available. So that thing people are warning about with 100% only applies for a few minutes.

 

[Rocky_H]

should be uber simple to program, the data is there, just not displayed.

It's worse than that. They already have the programming; it used to do exactly that. Tesla removed that feature.

 

[Gokada]

The battery will not accept any charge at or under freezing for sure. You can see it clearly on your regen bar, you won't have any regen either at those temps. The actual temperature required depends on the power you want to push in the battery. Supercharging at maximum speed requires a higher temperature than level 2 charging. I'm under the impression that 120V 12A charging probably requires the same thing as level 2. I'm pretty sure this has changed over time in various software updates. Currently it's somewhere between 4 and 8 degrees C if I remember correctly. Don't quote me here, it's an approximation. It could be 10C... I'd need to check again with scanmytesla the next time I leave my car parked outside...
As far as heating the battery beforehand... driving the car will warm it slowly up to a point. Newer cars with heatpump scavenge some heat to warm the cabin, but even that has evolved with software udpates. I'd say just let it plugged and eventually it will charge.

I just got the car 2 days ago and I’m learning a lot. Just read about the heat pump yesterday. So much to learn. I thought I was doing my due diligence through my research but now that I actually have one, things I never thought about are coming to light. Cheers!

 

[Velcade]

The car is REALLY GOOD at estimating range and knowing when you need to charge. It's OK to trust it

I found this to be true last week. It was right at 0'F and I had a trip to make. Made it home with 18% left and the car estimated I'd make it back with 17%. I've found through the winter, really the only time I'm paying attention to range, that the vehicle does a great job of estimating remaining battery.

 

[rodmacpherson]

If you had owned a Nissan LEAF ‘once upon a time’ you never ever would have problem with Tesla’s range estimation!!

Yes, The LEAF estimates (at least in my 2012) have to be taken with a truckload of salt.

 

[dannycamps]

I just got the car 2 days ago and I’m learning a lot. Just read about the heat pump yesterday. So much to learn. I thought I was doing my due diligence through my research but now that I actually have one, things I never thought about are coming to light. Cheers!

So how did you do getting home?

 

[herbicider]

This still surprises me that people don't know the effects of speed and weather on range. Personally, I would not try to do a 220 mile round trip at highway speeds in the summer on 80% of a charge!

Quick rule of thumb:

EPA range estimate is that you will get over 3 miles of range for each percent of SOC used... this is a fantasy at highway speeds (75 to 85 mph).

Real world summer range with real world weather (wind, rain, etc) you will get approximately 2 miles of range for each percent of SOC used. On an 80% charge your "real" summer range is around 160 miles... not 220, let alone 268. If I had 90% charge, with good weather (dead calm, 75F dry roads) I would do a 220 mile round trip without concern but as stated, that is for perfect weather and with my high tolerance for low SOC without getting range anxiety. I never plan on perfect weather for a road trip.

Real world winter range (light snow, cold, windy) 1.5 miles for each percent of battery used.

ALL OF THESE NUMBERS CAN BE IMPROVED BY SLOWING DOWN, OR (not controllable by you) DRIVING IN "PERFECT" (for that season) WEATHER.

Later,

Keith

I use percentage on my battery level and I found my 18 AWD's consumption @75mph is ~2miles/1% in WI winter (~340 kw/mile) and ~3miles/1% (~270 kw/mile) in summer commuting between MKE and CHI. And yes I always charge to 90% in winter and 80% in summer. I don't dial my AC/Heater to much tho.

 

[Fourdoor]

Thanks for posting.
The cars range computer should really take ambient temperature into account.
Once you get below 50F your Wh/mi go up noticeably, and once in the 20s-30Fs significantly.
Between the cars temperature sensor, local weather data using GPS + internet, and just general time of year (its winter).. it could have saved you some trouble by giving you a reasonable range projection from the get-go. If the roads had been wet at all, you would have burned through your range another 10-20% faster too and not made it home.
Given how long you coasted at 0, even changes to prevailing winds could have had a big impact.

The displayed range is a fantasy number based on EPA rating and SOC. The real calculated range is displayed in the energy use graph, and the car warned the OP's wife about it when it routed her to a Supercharger rather than routing her directly home.

Keith

PS: I am the first to bitch and moan about problems with Tesla's software, but its actual range calculations are pretty darn good.

 

[Fourdoor]

I have used several Chargepoint+ stations that were level 2 J1772 AC chargers. Was the chargepoint charger you were trying to use a DC CCS fastcharger? If so, the Tesla adapter will not attach to the top portion of the CCS connector, even though it looks like it should. I believe the top connector on the CCS cable only supplies power while AC charging? If your car supports CCS, you could purchase the Tesla adapter when they start selling it in the US.

This may already have been answered since I haven't been on line for a day or so, but the top portion of the CCS connector is for communications only, all of the power flows through the large DC pins on the bottom. If you look into the actual CCS connector you will see that the top portion only has 3 pins instead of the 5 pins used in a J1772 connector.

Keith