LR AWD Battery Issue?

[TheSocey]

I’m currently on a trip. While traveling I stopped at a supercharger and wanted to charge to 100%. The battery was getting close, so I started watching it closely. When I first plugged in, the charging amps were at 48 amps, when I got close to the end of the charge I noticed the charging amps dropped to 35 amps.

I was showing about 304 miles of range and couldn’t wait any longer. So I left. When I arrived at my destination ( about 50 miles) I was showing About 250 miles, but I switched the meter over to read by percentage and I show 80%...

Am I missing something here? Only 8500 miles on the car and I don’t have the ability to try and plug in right now. I tried a “restart” (by holding both steering wheel buttons down until it showed a “T” on the screen.

Any ideas?

 

[Tam]

....Any ideas?

So, what are your concerns questions?

Are you asking why it takes too long to charge your battery while on a road trip?

On a road trip, I prefer to charge up to 80% because I don't want to wait for a slower charging rate to 90% and an extremely slowest charging rate to 100%.

Yes, I can charge to 100% but it would take more than 1 hour or even more. It can even take more than 2 hours if it needs to recalculate itself during the 100% charging.

That's why you should not charge fully or near full while you are on Supercharger.

It's fine to do that while you are resting at a destination charger or at home.

 

[user212_nr]

Am I missing something here? Only 8500 miles on the car and I don’t have the ability to try and plug in right now. I tried a “restart” (by holding both steering wheel buttons down until it showed a “T” on the screen.

You should not be charging to 100% or even 80% on a road trip unless you have no alternative. You want to drive the car until it about 10% and then charge to 40% or whatever number is the minimum needed to reach the next supercharger.

The fastest charge rate is 0-40% and the slowest is at 80-100%. Therefore, there is no point to take the last 20% at a supercharger. The faster charge more than makes up for the additional time pulling off the road and charging.

Check out this tool which will run some of the numbers for you

A Better Routeplanner

 

[Zoomit]

That's why you should not charge fully or near full while you are on Supercharger.

It's fine to do that while you are resting at a destination charger or at home.

To be clear, it’s perfectly fine charging to 100% at a Supercharger from the car's perspective. There’s no real difference in how the battery gets to it’s “charge complete” state. However, it might cost more, be less convenient, or displace others from using the stall.

If you need to charge to 100% and there are no other cars waiting, go ahead and use the Supercharger.

 

[Stretch2727]

I’m currently on a trip. While traveling I stopped at a supercharger and wanted to charge to 100%. The battery was getting close, so I started watching it closely. When I first plugged in, the charging amps were at 48 amps, when I got close to the end of the charge I noticed the charging amps dropped to 35 amps.

I was showing about 304 miles of range and couldn’t wait any longer. So I left. When I arrived at my destination ( about 50 miles) I was showing About 250 miles, but I switched the meter over to read by percentage and I show 80%...

Am I missing something here? Only 8500 miles on the car and I don’t have the ability to try and plug in right now. I tried a “restart” (by holding both steering wheel buttons down until it showed a “T” on the screen.

Any ideas?

Not sure, but I think your concern was the tapering of the charge as it approached 100%. This is perfectly normal. As the battery approaches a full charge some of the cells will stop taking a charge. The tapering (reduced charging rate) allows the battery management system to level all the batteries at the same voltage. It is also important for battery life and reduces the stress on the batteries.

 

[TheSocey]

I guess part of my concern is the battery only charging to 304 miles, but I supposed it was still charging...

If I get home and allow to charge to 100%, will this somehow recalibrate the system? If rated range is 322 miles, and Im seeing 304, that seems like a significant drop for only 8500 miles

 

[camalaio]

I guess part of my concern is the battery only charging to 304 miles, but I supposed it was still charging...

If I get home and allow to charge to 100%, will this somehow recalibrate the system? If rated range is 322 miles, and Im seeing 304, that seems like a significant drop for only 8500 miles

If you didn't actually charge to 100% when you saw 304mi (which seems to be the case?) then 304 is not your max range. 250mi at 80% implies something more like 313 at 100%. That's a 3% drop or so: totally normal for this to happen when new, if a bit frustrating. The degradation slows down a lot after this, it's not a linear trend.

Your battery also needs to be at 25C (77F) or above to report full range. I don't know what temps you were in, but if you had been charging overnight outside it might not be up to temp.

You can check your 100% range estimate (and see if it's reduced due to cold) with this method, no charging required: Tip: Check amount locked out due to cold via app

@user212_nr they were charging at 48A, implying L2 charging - perfect time to charge to a high SoC. Even better that they pulled it just before 100% really!

 

[Tam]

...You should not be charging to 100% or even 80% on a road trip...

That contradicts the advice from:

The Rules of Model S Road Tripping

"Never, ever hesitate to use 100% Charge. Ever."

As your battery gets to near empty, the voltage gets lower, which means the current drawn will be higher, which means you stress the cells more.

When your battery is near empty, at 20% certain functions are cut off or redirected such as Sentry mode, HVAC...

At certain low level, your 12V charging might be cut off as well which means if it's depleted, your car might die even before your main battery gauge has ever reached 0 miles.

Avoid being in a low state of charge as much as possible.

 

[Tam]

I guess part of my concern is the battery only charging to 304 miles, but I supposed it was still charging...

If I get home and allow to charge to 100%, will this somehow recalibrate the system? If rated range is 322 miles, and Im seeing 304, that seems like a significant drop for only 8500 miles

If you are concerned about battery degradation:

1) you need to know that Tesla guarantees only 70% capacity, so you can worry but you can't claim coverage until then.

2) Your battery gauge will drift off to display lower miles so to minimize that miscalculation, Tesla Service Center recommends you to at least charge daily at 90%. It's fine to charge anywhere from 50 to 90% but if you don't follow what Tesla says, the calculation drifts might get worse.

3) To measure your battery degradation, you need to compare 100% to 100% and not with other numbers such 90% to 90%. You might need to do that several times because it might need to recalibrate to get a correct calculation.

My 2018 Model 3 LR at 18,575 miles has 298.7 miles out of original 310 miles at 100%

 

[KenC]

I’m currently on a trip. While traveling I stopped at a supercharger and wanted to charge to 100%. The battery was getting close, so I started watching it closely. When I first plugged in, the charging amps were at 48 amps, when I got close to the end of the charge I noticed the charging amps dropped to 35 amps.

I was showing about 304 miles of range and couldn’t wait any longer. So I left. When I arrived at my destination ( about 50 miles) I was showing About 250 miles, but I switched the meter over to read by percentage and I show 80%...

Am I missing something here? Only 8500 miles on the car and I don’t have the ability to try and plug in right now. I tried a “restart” (by holding both steering wheel buttons down until it showed a “T” on the screen.

Any ideas?

Not really optimal to be charging to 100%, if it's not needed. That will accelerate degradation. Here's the charge curve for the Model 3. You'll see it starts to slow down after 45% SOC, and once you're above 80%, it's almost trickle charging! I don't think I've ever charged above 80% at a SC.

 

[TMThree]

As your battery gets to near empty, the voltage gets lower, which means the current drawn will be higher, which means you stress the cells more.

When your battery is near empty, at 20% certain functions are cut off or redirected such as Sentry mode, HVAC...

It doesn't hurt it going under 20%. The reason for those features to be disabled is so you aren't left stranded because sentry drained the last bit of battery and you can't make it to a charger.

You obviously never want to drain a lithuim battery completely, but Tesla has a few % reserved on the bottom to help.

Additionally, while 90-100% SoC is bad in hot temps, being under 10% in low temps is also bad for cell stress. So if low SoC is bad for it or not will depend mostly on the climate.

Ideally, you'd keep your car between 10-60% most of the time. With no real benefit going below 50%, hence why its the lowest you can set your charge limit to.

Also... for long term storage, you can see a sharp rise in capacity loss when stored over 50%:

 

[TMThree]

My 2018 Model 3 LR at 18,575 miles has 298.7 miles out of original 310 miles at 100%

16,000 miles. 325 miles originally. 65% daily charge. 80-90% intermittently.

It's still within the 325 mile ballpark, though the average is down slightly. You can see from my SoC (in orange) that the car basically sits around since mid Feb, I don't driven it often now, so the charge results may be skewed a bit.

 

[Zoomit]

Your battery also needs to be at 25C (77F) or above to report full range.

I have seen this as well, though I’m surprised it’s this high. Did you derive this temperature empirically, or do you have another source?

 

[Tam]

...Ideally, you'd keep your car between 10-60% most of the time... With no real benefit going below 50%, hence why its the lowest you can set your charge limit to.

The article is talking about STORAGE stress, not driving stress.

We are talking about driving stress that needs serious Amperes drawn from the cells.

 

[user212_nr]

That contradicts the advice from:

The Rules of Model S Road Tripping

"Never, ever hesitate to use 100% Charge. Ever."

That is not an instruction to always charge to 100%. Only at home or if you have no alternative at a supercharger. Its not for the battery it is for time.

Sorry on behalf of whoever wrote that, if it was not clear.

When your battery is near empty, at 20% certain functions are cut off or redirected such as Sentry mode, HVAC...

HVAC works just fine, and sentry mode is not applicable to driving. I'm not aware of any limitations while driving.

As your battery gets to near empty, the voltage gets lower, which means the current drawn will be higher, which means you stress the cells more.

The amount of current is inversely proportional to the charge time. That means the higher the current, the faster the charge.

It is very advisable to road trip this way, and in fact it is not really possible otherwise. Charging to 100% will more than double your charge times on a road trip.

The article that you are quoting says clearly "If your next charging station isn't pushing your range, then you should probably stop charging when the power starts ramping down (except at a Supercharger)."

Having seen your interpretation of that guide, it is definitively poorly written and misleading. The author knows his stuff and means well, but he is overly verbose on certain topics and buries important details in the footnotes.

 

[Tam]

...HVAC works just fine, and sentry mode is not applicable to driving. I'm not aware of any limitations while driving...

I guess you don't drive in a subzero environment when HVAC does not only mean cooling air but also means heating.

The cabin heater will be reduced or cut off when the battery is low.

 

[Zoomit]

The cabin heater will be reduced or cut off when the battery is low.

Have you seen this limit in the Model 3?

Here’s a video of Bjorn Nyland blasting the heat at “Hi” (6+kW) at -1% indicated SoC (15:00). The car is stationary, if that makes a difference.

 

[user212_nr]

I guess you don't drive in a subzero environment when HVAC does not only mean cooling air but also means heating.

The cabin heater will be reduced or cut off when the battery is low.

Obviously you are the one who has never driven below 20% in a subzero environment. Absolutely it works.

Have you ever been in a subzero environment? Do you know that subzero environments are fatal to the human body? Do you think that I pull over at 20% and put a jacket on?

 

[Tam]

...Have you ever been in a subzero environment?...

No. I have never driven my Tesla in subzero environment but I've been driven it sometimes in 30's F weather.

When my SOC is low I think around 20% or so, I would get a message: "Heating and A/C reduced"

 

[user212_nr]

No. I have never driven my Tesla in subzero environment but I've been driven it sometimes in 30's F weather.

When my SOC is low I think around 20% or so, I would get a message: "Heating and A/C reduced"

Yeah, at 0 miles.