Ran out of Charge! A cautionary tale!

[rbtower2]

So I heard you are supposed to once in a while run the battery all the way down in order to help balance out the battery and use all the cells once in a while. A lot of people said it will still run below 0 just really slow since the battery has a buffer built in. So I decided to run it down last night. I pulled in to the mall parking lot with 2 miles and decided to drive around till i was about to hit 0 and then go plug it into the supercharger. Well as soon as the car hit 1 mile remaining it said car shutting down, pull over immediately. so i bee lined it to the supercharger and made it close but when I stopped to put it in reverse to back it into the supercharger, the car went into park and wouldnt let me shift anymore.Luckily there was a model X with a bunch of guys charging next to me so I put the car in tow mode and asked them to push me back into the spot!
It took forever for the car to start accepting a charge. For a good 5 minutes it was only accepting like 3 kwh from the supercharger and only started really "supercharging" once it reached 10% battery.
Anyone else have this happen? Are you not supposed to run the battery all the way down once in a while? Any input would be appreciated!

 

[rooter]

The car doesn't really know where the boundaries are until it's calibrated, and that's what you've done now. Most of the time you should have about a 4 mile cushion after 0, but not always. Sometimes 0 is 0.

Balancing the batteries happens when you charge above 93%. I do this about once/month, otherwise charging to 90%.

 

[SabrToothSqrl]

I also heard you are supposed to put butter on burns, and let wounds 'air out'.
Neither of which is true.
No. don't do this. Just plug in.

 

[Tesomega]

Anyone else have this happen?

If your battery is below 10%, yes the charge rate will be super slow.

Are you not supposed to run the battery all the way down once in a while?

I have heard this (run to 0, charge to 100%) in the context of measuring battery capacity/degradation.

I normally just balance batteries charging to 95% (I believe it is about 93%-94%) that BMS triggers balancing cells.

 

[ewoodrick]

1st mistake - listening to the self proclaimed experts here.
2nd mistake - running battery to 0%

Taking a battery to zero is IMHO one of the hardest things that you can do to a battery. And in any modern vehicle, no power keeps computers from running.

Charging to 100% and leaving it there isn't the best thing to do. Taking to 0% damages the battery. IMHO

 

[SabrToothSqrl]

I always invert my car before plugging in. Helps the electrons flow better

 

[TexasEV]

Are you not supposed to run the battery all the way down once in a while? Any input would be appreciated!

No you are not. Stop listening to self-proclaimed experts and just let the battery management system manage the battery. If this was good for your car, it would be recommended in the manual. It’s not.

 

[ucmndd]

No you are not. Stop listening to self-proclaimed experts and just let the battery management system manage the battery. If this was good for your car, it would be recommended in the manual. It’s not.

I SWEAR there used to be a page in the manual that said to occasionally drive your car around the parking lot at the supercharger until you hit zero miles and then immediately charge.

 

[SpudLime]

Balancing the batteries happens when you charge above 93%. I do this about once/month, otherwise charging to 90%.

According to Elon and the guy in charge of batteries at Tesla charging 60-80% its best..

 

[Lasttoy]

I have 130k miles, never done any of that bs. Been to zero purely by mistake sightseeing all over usa.
Here is only advice in manual

 

[TexasEV]

According to Elon and the guy in charge of batteries at Tesla charging 60-80% its best..

Define best.

There may be a statistically significant difference in capacity in the lab after many years, but there’s never been shown to be a clinically meaningful difference in the car. I charged my Model S to 90% every night for five years and had 5% loss in capacity. Owners who limited their charge rate did no better. Even if there was a 1 or 2 mile range difference, would that be meaningful to anyone? Not to me.

 

[Electricfan]

This site says avoid total discharge as much as possible.

https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

 

[HankLloydRight]

Taking to 0% damages the battery. IMHO

There's no such thing as taking a Tesla battery to 0%. There's ALWAYS a small kWh buffer in the battery when the car reads 0%. It's not actually 0%. That's on purpose to prevent humans from damaging the battery. The BMS is programmed to shut down the traction pack before any damage can occur. Once that happens, the car is only running on the 12v battery for the electronics, and that doesn't last long. Once the 12v dies, you can no longer get the car into 'tow mode' to push it to a charging station. Then you'll need a flatbed.

If you want to calibrate the battery, sure, run it down low, but like 5%-10% and then up to 93%-100% to balance the pack out. But never run it to 0%, that will only get you stranded.

 

[SpudLime]

Define best.

There may be a statistically significant difference in capacity in the lab after many years, but there’s never been shown to be a clinically meaningful difference in the car. I charged my Model S to 90% every night for five years and had 5% loss in capacity. Owners who limited their charge rate did no better. Even if there was a 1 or 2 mile range difference, would that be meaningful to anyone? Not to me.

Just saying this has been asked many times. Im going by the CEO and the guy who is head of the battery division.

Elon:
Elon Musk on Twitter

Head of the battery division.

Jeff Dahn's recommendation on long term battery preservation


Im trusting those guys over the internet.

 

[SSedan]

After a year of shallow discharge and only charging to 70-80% it appeared my car was degrading the battery fast. Last weekend I ran it down to 7% and charged back up to 100% and gained 6miles back vs last time I charged to 100%. Hope to try again soon.
Point being I think it is reasonable to go down to 5% back up to 100% once in awhile to help the computer calibrate. 0% is getting carried away though.

 

[TexasEV]

After a year of shallow discharge and only charging to 70-80% it appeared my car was degrading the battery fast. Last weekend I ran it down to 7% and charged back up to 100% and gained 6miles back vs last time I charged to 100%. Hope to try again soon.
Point being I think it is reasonable to go down to 5% back up to 100% once in awhile to help the computer calibrate. 0% is getting carried away though.

That's a different issue. The OP thought it would be good for the battery. It's not. As you say, it just improves the accuracy of the estimated SOC.

 

[SSedan]

Thank you for making that point more directly than I did.

I should have been clearer in saying it helps calibration but not actual battery health.

 

[mongo]

If you want to calibrate the battery, sure, run it down low, but like 5%-10% and then up to 93%-100% to balance the pack out.

You start out talking about calibration, but then end with balance, so I'm not sure if you typoed/ misspoke at the end. The Pack can balance at any SOC. Each cell group has voltage monitoring and charge adjusting circuitry.

 

[HankLloydRight]

Yes, I meant calibrate the BMS/SOC calculations at both ends of charge state.

 

[dark cloud]

So maybe @rbtower2 can post back and describe how his range has changed from this event?