# Power Meter - Dots for less power?



## BLDRN3R (Feb 28, 2018)

So I noticed this the other day and decided to see if it would come back.

As the battery in my M3 gets lower and lower I see dots beginning to appear on the far right edge of the power meter (see attached photo). The most I have seen is three dots when I was down to about 50 miles of range.

Has anyone else seen these or have an explanation of what they are? It reminds me of a 'redline' in an ICE car to show where power output caps, esp. as battery gets lower and theres more of a necessity to preserve range/performance.

Will post more photos this week as the dots increase.


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## garsh (Apr 4, 2016)

My guess (based on how my Leaf behaves):

A battery with a low state of charge is physically unable to deliver as much current as one that's well-charged. So as your battery gets really low, this is probably how the car lets you know that you will not be able to accelerate as hard as you usually can. Those dots represent "currently unreachable" power.


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## SoFlaModel3 (Apr 15, 2017)

I've seen that before with higher capacity as well. My gut feeling was that it was more about battery temp or some other factor that simply limited max output.

That said, even flooring the car the bar never hits the end anyway


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## John (Apr 16, 2016)

The dots can appear on either end of the meter, and indicate the max allowed (regent or power) in that direction. Various reasons: state of charge, current conditioning state, temp.


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## SoFlaModel3 (Apr 15, 2017)

SoFlaModel3 said:


> I've seen that before with higher capacity as well. My gut feeling was that it was more about battery temp or some other factor that simply limited max output.
> 
> That said, even flooring the car the bar never hits the end anyway


Following up to reverse what I said. Either I never noticed or this changed with the latest update but the bar most certainly hits the end under full throttle. It's just the regen side that never hits the end


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## MelindaV (Apr 2, 2016)

SoFlaModel3 said:


> It's just the regen side that never hits the end


Then you need to find a bigger hill to go down than Florida has


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## SoFlaModel3 (Apr 15, 2017)

MelindaV said:


> Then you need to find a bigger hill to go down than Florida has


I would enlist anyone's help to find a hill here


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## MelindaV (Apr 2, 2016)

SoFlaModel3 said:


> I would enlist anyone's help to find a hill here


come west. we have all the best things, like mountains


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## SoFlaModel3 (Apr 15, 2017)

MelindaV said:


> come west. we have all the best things, like mountains


I always like my travel west, that is until I have to come back home and lose 3 hours.


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## mswlogo (Oct 8, 2018)

A friend of mine had those dots (on the RIGHT) show up this morning (RWD LR, with Xi3 Snows and never had any issue with snow tire regen)

He had 33 miles left on his battery after a long drive and parked it at -2F overnight at home.

He could have charged it at home, but at work he can charge for free 10 miles away. I told him that's a bad idea to leave it that low in such extreme temps.

Any way he had several dots on the right and a snow flake. Which is fine and expected and he reached work fine.

But, what is odd, is he had FULL REGEN?

Is the battery in some sort of "Extended Range" mode and throwing the regen rules out? Is Regen going into Heat?


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## JWardell (May 9, 2016)

Teslas have both regen and discharge power limits. The UI will show these as dots in the display. Regen limiting stars to kick in below 50F and will go all the way to zero if the battery is near freezing. A battery chilled below freezing will also begin to show a discharge limit as well, I've seen 4-5 dots on the right side myself.

Discharging power will also be limited if you are close to a fully discharged battery. The car only allows a small amount of power to be applied, so voltage doesn't drop below critical levels.
Look at this recent tweet:

__ https://twitter.com/i/web/status/1087023276369555456


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## mswlogo (Oct 8, 2018)

JWardell said:


> Teslas have both regen and discharge power limits. The UI will show these as dots in the display. Regen limiting stars to kick in below 50F and will go all the way to zero if the battery is near freezing. A battery chilled below freezing will also begin to show a discharge limit as well, I've seen 4-5 dots on the right side myself.
> 
> Discharging power will also be limited if you are close to a fully discharged battery. The car only allows a small amount of power to be applied, so voltage doesn't drop below critical levels.
> Look at this recent tweet:
> ...


I get that. Why is full regen available with his frozen battery, snow flake and limited power?


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## mswlogo (Oct 8, 2018)

I wonder if when the battery is super low it can take the full regen even if the battery is very cold.

The only time I see over 100 kw on a supercharger is when my battery is super low (like below 20%)


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## Bokonon (Apr 13, 2017)

mswlogo said:


> I get that. Why is full regen available with his frozen battery, snow flake and limited power?


Just to confirm... did his screen only say he had full regen, or did he report experiencing full regen after he had started driving?

The reason I ask is because sometimes I don't see my "actual" number of regen dots until I actually try to use regen. For example, I may start a drive with ~8 regen dots displayed on the screen, but as soon as I actually use regen to brake, 6 more dots will suddenly appear, and regen will be capped at the 14-dot level.

That said, I've only seen that happen with *some* number of dots displayed when starting a drive, not zero dots.


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## iChris93 (Feb 3, 2017)

Bokonon said:


> Just to confirm... did his screen only say he had full regen, or did he report experiencing full regen after he had started driving?
> 
> The reason I ask is because sometimes I don't see my "actual" number of regen dots until I actually try to use regen. For example, I may start a drive with ~8 regen dots displayed on the screen, but as soon as I actually use regen to brake, 6 more dots will suddenly appear, and regen will be capped at the 14-dot level.
> 
> That said, I've only seen that happen with *some* number of dots displayed when starting a drive, not zero dots.


I'll go further and say sometimes I don't see the dots until I put the car into drive or reverse.


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## mswlogo (Oct 8, 2018)

Anoteher data point. When he plugged in at his work (With a snow flake and limited power) -4F over night and -1F when he drove in.
It went straight to 24 mph charge rate. Fastest he's seen at work.

Hmmm, I wonder if it would be much cheaper to operate by keeping our batteries at low SOC.
You get Full Regen when cold and the charger won't waste energy heating battery to charge it.

How low is practical I don't know.


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## mswlogo (Oct 8, 2018)

Bokonon said:


> Just to confirm... did his screen only say he had full regen, or did he report experiencing full regen after he had started driving?
> 
> The reason I ask is because sometimes I don't see my "actual" number of regen dots until I actually try to use regen. For example, I may start a drive with ~8 regen dots displayed on the screen, but as soon as I actually use regen to brake, 6 more dots will suddenly appear, and regen will be capped at the 14-dot level.
> 
> That said, I've only seen that happen with *some* number of dots displayed when starting a drive, not zero dots.


He definitely experienced full regen. I asked him that too.


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## mswlogo (Oct 8, 2018)

iChris93 said:


> I'll go further and say sometimes I don't see the dots until I put the car into drive or reverse.


He knows that, and I know that. And he felt it.

It makes sense. Superchargers can charge MUCH faster on a low battery.


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## mswlogo (Oct 8, 2018)

You can see he's been on the road for only 10 minutes. Still with very cold battery. Still very cold out. With Full Regen showing and by feel.


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## JWardell (May 9, 2016)

mswlogo said:


> I get that. Why is full regen available with his frozen battery, snow flake and limited power?


His battery isn't cold at all, confirmed by mentioning he was just driving hard in a rally. It might be very cold outside but he's heated the battery by driving hard (which is much more effective than charging BTW!). That's why there's no regen limit, but power is limited because it is almost depleted.



mswlogo said:


> You can see he's been on the road for only 10 minutes. Still with very cold battery. Still very cold out. With Full Regen showing and by feel.


Now this is more curious, because your battery is warm enough for full regen, but still showing snowflake. Maybe temps are still limiting a small amount of battery, but if snowflake is based on percentage of available lost due to cold (instead of percentage of total lost), then it is enough to display.

State of charge is still a bit of a mystery as the displayed SOC is not the same as what the battery calculates. We can clearly read several SOC values communicated by the BMS, inlcuding one labeled UI SOC, and yet the display often shows lower. You might notice this same issue if you compare Teslafi's recorded levels with what is shown on screen. I think Tesla is applying a secondary thermal correction factor just within the computer. Or maybe we'll discover more soon.


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## mswlogo (Oct 8, 2018)

JWardell said:


> His battery isn't cold at all, confirmed by mentioning he was just driving hard in a rally. It might be very cold outside but he's heated the battery by driving hard (which is much more effective than charging BTW!). That's why there's no regen limit, but power is limited because it is almost depleted.
> 
> Now this is more curious, because your battery is warm enough for full regen, but still showing snowflake. Maybe temps are still limiting a small amount of battery, but if snowflake is based on percentage of available lost due to cold (instead of percentage of total lost), then it is enough to display.
> 
> State of charge is still a bit of a mystery as the displayed SOC is not the same as what the battery calculates. We can clearly read several SOC values communicated by the BMS, inlcuding one labeled UI SOC, and yet the display often shows lower. You might notice this same issue if you compare Teslafi's recorded levels with what is shown on screen. I think Tesla is applying a secondary thermal correction factor just within the computer. Or maybe we'll discover more soon.


I was not referring to your Twitter post. I was referring to my friend.

I assure you, his battery is NOT "warm enough" for anything. He is showing a freaking snowflake.
He has full regen because his battery is LOW SOC !!

My battery was much warmer than his this morning because it was in an attached garage (35F) and I had no regen this morning (no snow flake either) but it was at 85% SOC.
And now that it's been outdoors all day it now shows a snow flake as well.

Even at 20-30F if I had no regen to start it would take 70 miles and an hour of driving before I'd get full regen. He only drove 5 miles.

We know lower state of charge can accept more watts. Just didn't know it could be low enough to get full regen at these temps.


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## Long Ranger (Jun 1, 2018)

mswlogo said:


> Hmmm, I wonder if it would be much cheaper to operate by keeping our batteries at low SOC.
> You get Full Regen when cold and the charger won't waste energy heating battery to charge it.
> 
> How low is practical I don't know.


Some interesting data points here, but I think you and your friend would be better served by focusing less on charging costs and focusing more on long term health of the battery. The cost of charging is pretty insignificant in the overall total cost of ownership of this car.

Testing the limits of low SOC and low temperatures is typically a recipe for disaster with lithium batteries. You're really putting a lot of faith in the Tesla engineers to protect that battery. Now, I think they do a great job of that, but they do have to make tradeoff decisions when you push the limits.

When temperature is low, I believe the limited regen that you typically see isn't truly the limit of the battery, it's a limit that Tesla implements to maximize long term battery life. Now when SOC is also very low, they also need to worry about battery damage due to low SOC. I suspect they allow full regen at low SOC + low temp because they are more worried about low SOC than about high charging current at low temps and they want to keep your SOC as high as possible. Just because they allow full regen in those conditions doesn't mean that it's good for your battery. They are likely just choosing the lesser of two evils.


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## mswlogo (Oct 8, 2018)

Long Ranger said:


> Some interesting data points here, but I think you and your friend would be better served by focusing less on charging costs and focusing more on long term health of the battery. The cost of charging is pretty insignificant in the overall total cost of ownership of this car.
> 
> Testing the limits of low SOC and low temperatures is typically a recipe for disaster with lithium batteries. You're really putting a lot of faith in the Tesla engineers to protect that battery. Now, I think they do a great job of that, but they do have to make tradeoff decisions when you push the limits.
> 
> When temperature is low, I believe the limited regen that you typically see isn't truly the limit of the battery, it's a limit that Tesla implements to maximize long term battery life. Now when SOC is also very low, they also need to worry about battery damage due to low SOC. I suspect they allow full regen at low SOC + low temp because they are more worried about low SOC than about high charging current at low temps and they want to keep your SOC as high as possible. Just because they allow full regen in those conditions doesn't mean that it's good for your battery. They are likely just choosing the lesser of two evils.


First, I told him it was not a good idea and I had told him that it might have throw regen rules out the window with the battery that low. And it's choosing to Charge what it can when it can.

The thing is, I don't think you or I know why it's not doing regen in these conditions. I think there is nothing wrong with his car either, which is what he was concerned about. My hunch is that the battery can accept the regen current when the battery is low. And it's not because it's choosing the lesser of two evils. But it's certainly a possibility. He was low, but not that low.

Not sure if the 33 miles is adjusted for (snow flake) or not.

We also don't know how harmful doing what he did is. I personally would avoid letting it stand at low SOC in such cold temps over night.


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## Jay Jay (Oct 26, 2018)

Long Ranger said:


> Some interesting data points here, but I think you and your friend would be better served by focusing less on charging costs and focusing more on long term health of the battery. The cost of charging is pretty insignificant in the overall total cost of ownership of this car.


This! Not worth waiting to charge free at work in this situation.


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## mswlogo (Oct 8, 2018)

Jay Jay said:


> This! Not worth waiting to charge free at work in this situation.


So folks that don't know the answer rather focus on this.

He parks in 2 places for many hours. Both have charging. One is free. The other is $0.23 kWh. He had like 40 miles to start a 10 mile trip. I bet 99% of folks would have done the same.

I asked why regen returned. Nobody has any idea if this is harmful to the battery. Maybe it's a great idea to run lower state of charge and doesn't hurt the battery at all. I'm curious how low the battery has to be for this full regen to return.

People run lower SOC for faster Supercharging. Maybe it works for regen in cold weather too. Is it practical? I don't know? Is it healthy? I don't know.


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## Long Ranger (Jun 1, 2018)

mswlogo said:


> He parks in 2 places for many hours. Both have charging. One is free. The other is $0.23 kWh. He had like 40 miles to start a 10 mile trip. I bet 99% of folks would have done the same.


 Last weekend I finished a long drive with 45 miles left and the car warned me that I should plug in now because the battery would lose capacity once it gets cold. I think most people would follow that advice from the car. Even at $0.23/kWh it would be less than $2 to add another 10% SOC and have a much more comfortable margin.



mswlogo said:


> I asked why regen returned. Nobody has any idea if this is harmful to the battery. Maybe it's a great idea to run lower state of charge and doesn't hurt the battery at all. I'm curious how low the battery has to be for this full regen to return.
> 
> People run lower SOC for faster Supercharging. Maybe it works for regen in cold weather too. Is it practical? I don't know? Is it healthy? I don't know.


Even if full regen at low SOC and low temp isn't harmful to the battery, I still can't understand why you'd want to run the car like this. No extra range for unforseen drives, constant range anxiety, worse acceleration.

Now in terms of the technical details you are looking for on regen, I can't answer that because it depends upon too many Tesla specific factors. I can confirm that I've seen lithium battery graphs that show less risk of lithium plating as the SOC drops below 15% (allowing a higher charge rate). Maybe that fully explains the full regen. But I still contend that it's pretty likely that Tesla reduces that safety margin as SOC approaches 0%. When you're driving at low SOC the car doesn't know when your next charge will be, so it would make sense to give you more regen if the risk of fast charging is less than the low SOC risk.

In terms of your question about whether running at low SOC doesn't hurt the battery at all, that's a pretty easy one. Low (or high) SOC does have a detrimental effect on battery capacity over the long term. Ideally, a lithium battery should be kept around 50% SOC for maximum life. You'll find lots of debate over how significant this is and the ideal range, but generally keeping in the 10-90% range is recommended. Below 10 (but never 0!) and above 90 is fine for short periods, but don't keep it like that. The miniscule damage slowly accumulates the longer the battery is kept at the SOC extremes.


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## TheHairyOne (Nov 28, 2018)

Glad I read this post, so I won’t get fearful if it happens to my car that the battery is prematurely failing or something.

I should register TeslaTraining.org and have a full course of graduating training videos. Curriculum updated when changes and new features occur. 
Driver certification available with levels of: we pray for others on the road, We Pray for you, good luck, approved, expert, trainer.

Alas I’m sure it’s be copyright infringement and shut down for other reasons as well.

Imagine a quiz like, enable EAP while in traffic but use accelerator to avoid getting cut off. Now roll down window and throw something at the car in front of you. 
What’s wrong with the screnario above? A.) it’s wrong to throw things, b.) it’s illadvised to accelerate while in EAP, c.) you should have disabled the camera to avoid self incrimination. 
Correct C was the best choice.


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## mswlogo (Oct 8, 2018)

Long Ranger said:


> Last weekend I finished a long drive with 45 miles left and the car warned me that I should plug in now because the battery would lose capacity once it gets cold. I think most people would follow that advice from the car. Even at $0.23/kWh it would be less than $2 to add another 10% SOC and have a much more comfortable margin.
> 
> Even if full regen at low SOC and low temp isn't harmful to the battery, I still can't understand why you'd want to run the car like this. No extra range for unforseen drives, constant range anxiety, worse acceleration.
> 
> ...


Maybe he had 50 miles when he parked it the night before. And he was well above 10% when he started his short trip. And he was close to 10% when he reached the charger. So your saying it's not safe to run to 10%.


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## Long Ranger (Jun 1, 2018)

mswlogo said:


> Maybe he had 50 miles when he parked it the night before. And he was well above 10% when he started his short trip. And he was close to 10% when he reached the charger. So your saying it's not safe to run to 10%.


I didn't say it wasn't safe to run down to 10%. It's fine to end your trip at 10% or less. It's just better for the battery not to leave it overnight at a low SOC like that. The less time the battery spends at really low or really high SOC, the better. The loss of capacity is a long term cumulative effect, so it's not something you would likely notice unless you do it frequently. However it's difficult to predict the exact long term effects on a given battery, so I lean towards not leaving it overnight at low SOC when it's easily avoidable.

Your initial post seemed to indicate that he had 33 miles on a warm battery and parked it overnight in temps of -2F. In that case, I'd definitely charge it some. If he had 50 miles, that's probably not as critical. However, I don't have any experience in temps like that.


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## mswlogo (Oct 8, 2018)

Long Ranger said:


> I didn't say it wasn't safe to run down to 10%. It's fine to end your trip at 10% or less. It's just better for the battery not to leave it overnight at a low SOC like that. The less time the battery spends at really low or really high SOC, the better. The loss of capacity is a long term cumulative effect, so it's not something you would likely notice unless you do it frequently. However it's difficult to predict the exact long term effects on a given battery, so I lean towards not leaving it overnight at low SOC when it's easily avoidable.
> 
> Your initial post seemed to indicate that he had 33 miles on a warm battery and parked it overnight in temps of -2F. In that case, I'd definitely charge it some. If he had 50 miles, that's probably not as critical. However, I don't have any experience in temps like that.


He was at 33 with 5 miles to go to get to his charger at work. He had already gone 5 and I'm sure at those cold temps he was probably 10 miles higher when he started and probably has some vampire drain overnight. And I'm not sure if the snow flake subtracts Mike's from miles left or not.

So your saying I shouldn't charge to 90% and leave it overnight either. Wouldn't that be the same thing? Which so think is the new recommendation.

When I say safe, I mean safe for battery longevity.


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## garsh (Apr 4, 2016)

mswlogo said:


> So your saying I shouldn't charge to 90% and leave it overnight either.


Charging to 90% is perfectly fine.


__ https://twitter.com/i/web/status/1068745921079345152


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## mswlogo (Oct 8, 2018)

garsh said:


> Charging to 90% is perfectly fine.
> 
> 
> __ https://twitter.com/i/web/status/1068745921079345152


And leaving it at 90% for extended period is safe too?
But letting it drop to 10% isn't?


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## garsh (Apr 4, 2016)

mswlogo said:


> And leaving it at 90% for extended period is safe too?
> But letting it drop to 10% isn't?


According to Musk's tweet, it's safe to charge up to 80%, and even 90%. Also according to musk, it's still safe to even go below 5%.

If you're talking about leaving it at these levels for an extended period of time, it depends on what you mean by "extended period". Are you thinking days? Weeks? Months? Also, is it going to be plugged in during this period of time?

For long term storage (months), I suggest setting the charge level to 50% and leaving the car plugged in. If you can't leave the car plugged in, then I would charge it to 90% before parking it.

For just a day or two, and leaving the car unplugged, 90% will be fine. Leaving it at 10% depends on the situation. If temperatures are well below freezing, then don't do this. Keep it above 20%. A cold-soaked battery loses much of its ability to provide power until it warms back up, and the Model 3 doesn't generate a whole lot of excess heat for warming up the battery. You'll wake up to a lot less range than you had when you parked the car. That said, it shouldn't hurt the battery's lifetime to park it at 10%, even in cold weather.

Also remember that the car loses about a mile a day when it's just parked. So if you park it at 10% for a week, it might be down to 6% when you start it again. And there have been software bugs in the past that cause the car to lose more than a mile per day, so I'd be wary of that happening as well.


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## mswlogo (Oct 8, 2018)

garsh said:


> According to Musk's tweet, it's safe to charge up to 80%, and even 90%. Also according to musk, it's still safe to even go below 5%.
> 
> If you're talking about leaving it at these levels for an extended period of time, it depends on what you mean by "extended period". Are you thinking days? Weeks? Months? Also, is it going to be plugged in during this period of time?
> 
> ...


It was left at like 15% for 8 hours (midnight to 8AM) at his home that he could have charged, very cold night 0F, with a 10 mile cold ride in the morning, which would have left him at around 9% at a free charger at his work that would leave him with a full battery by the time he leaves work.

Some folks baulked at this practice. I might not do it myself. But I certainly can't blame him for doing what he did and think it's within the "reasonable" parameters.

Some folks would argue what if you needed the car for an emergency or stuck in traffic on his way in and never leave the battery so low when there is opportunity to charge it (regardless of saving a few $$).

It was recommended why not add 10% charge. That's actually fairly awkward to do. Since the lowest target is 50%. So then you might syay you can lower the current.
Then you have to calculate what you need, and you set that so low it will probably do more heating than charging. It gets messy. Or you could use a 3rd party scheduler.
Keep in mind this was midnight after a long weekend and a lot driving.

I've read enough to know what folks "think" is good and not good.

Still very curious at what SOC regen becomes fully available again on a very cold battery.


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## mswlogo (Oct 8, 2018)

I had close to the same thing happen that happened to my friend.

You can see I have limited power, snow flake, 4F out. But I have almost full regen.

Normally I try to keep my battery higher. If it was higher, usually a snow flake and limited power come after losing all regen.

But because the battery has low SOC it gradually starts to accept regen as SOC goes down.

It was suggested that regen was enabled to "save the battery" in my friend's case. This clearly is not the case. The battery is low here but not that low. And as the battery got lower the regen gradually came back. But the snow flake didn't go away nor did the power limitation go away as I drove 30 miles. Because it's freakin cold out.


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## Frully (Aug 30, 2018)

mswlogo said:


> But, what is odd, is he had FULL REGEN?
> 
> Is the battery in some sort of "Extended Range" mode and throwing the regen rules out? Is Regen going into Heat?


Obvious statement: Regen is limited by how much power the battery can take.
Less obvious part: the colder the battery, or the more full the battery, the less it can take.
Less obviouser part: the more empty the battery the more it can take...at near completely empty, even if cold, the battery can take much more than a cold middle-charged battery.


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