Battery Life goes UP as car sits Idle

[Pg3ibew]

I was very cold This morning. Low 20s. I Got in my car and the EV miles Range said 17. I drove my bride to the store on all EV and the remaining EV miles Range said 14. She went into the store and I sat in the car with it ON. Listening to the radio and just PLAYING. A good 30 minutes. As I sat there, the EV Mileage Range went UP to 15, 16, 17, then 18.

 

Is this normal? Can someone explain it? Thanks!!

[murphy]

I was very cold This morning. Low 20s. I Got in my car and the EV miles Range said 17. I drove my bride to the store on all EV and the remaining EV miles Range said 14. She went into the store and I sat in the car with it ON. Listening to the radio and just PLAYING. A good 30 minutes. As I sat there, the EV Mileage Range went UP to 15, 16, 17, then 18.

 

Is this normal? Can someone explain it? Thanks!!

What was the outside temperature?  Battery efficiency drops as the temperature drops.  The battery gets air from the cabin so that can warm it up after being cold soaked over night.

[rbort]

No its not normal should be going down over time, unless you were plugged in.

 

-=>Raja.

[openair]

I've experienced this as well. What Murphy says is very possible but I've experienced this in 20c weather iirc. Imo it's an artifact of some time weighted calculations that are part of the range estimate.

[murphy]

To add to what openair said there is no known method to measure the charge in a battery.  It is based on mathematical calculations.  In otherwords a SWAG.

[rbort]

How can it be?  I've never seen my car go up while powered up.

 

Logic dictates that power ON draws 600w constantly from the battery.

 

Range is based on MPGe.  If you reset the MPGe meter recently and drive a little and stop, while stopped you constantly see the MPGe number dropping.  It only goes up while you're going down hill and regenerating, or coasting.  When accelerating it drops quickly, when stopped it continues to drop slowly.

 

The only time it can go UP while stopped is if the car is plugged in.  Then if your MPGe is going up, but you've driven 5 miles already, now you have gone 5 miles in less and less KWH used, (MPGe going up), and then the car will recalculate the range higher and higher for the remaining KWH in the battery.

 

You have something wrong with your car if you stop and sit there with it on and the range goes up from 14 to 18 miles in a half hour of drawing 600w out of the battery, maybe more if you're running heat or AC.  

 

-=>Raja.

[Pg3ibew]

How can it be?  I've never seen my car go up while powered up.

 

Logic dictates that power ON draws 600w constantly from the battery.

 

Range is based on MPGe.  If you reset the MPGe meter recently and drive a little and stop, while stopped you constantly see the MPGe number dropping.  It only goes up while you're going down hill and regenerating, or coasting.  When accelerating it drops quickly, when stopped it continues to drop slowly.

 

The only time it can go UP while stopped is if the car is plugged in.  Then if your MPGe is going up, but you've driven 5 miles already, now you have gone 5 miles in less and less KWH used, (MPGe going up), and then the car will recalculate the range higher and higher for the remaining KWH in the battery.

 

You have something wrong with your car if you stop and sit there with it on and the range goes up from 14 to 18 miles in a half hour of drawing 600w out of the battery, maybe more if you're running heat or AC.  

 

-=>Raja.

Let me elaborate here. It DEFINITELY went UP from 14 to 18 while sitting there, WITH THE CAR ON. In that 30 minutes, the outside temps did rise considerably from mid 20s to mid 30s F and I was sitting in the direct Sunlight. 

I am often early for work. And sit in the car with it ON. The EV numbers either stay the same or DROP. They will drop when I turn on the heater. But, it is still dark and very cold.

 

To go even further. I have gotten out of the car with an EV of 8. Come back to the car 7 hours later, temps rising by 20 degrees F and I will start the car and it will say EV 10 or 11. Depends on how much it warms up outside. 

 

Which leads me to believe the outside temps play a bigger role with the batteries than we know.

Edited February 12, 2017 at 11:35 PM by Pg3ibew

[rbort]

 

 

To go even further. I have gotten out of the car with an EV of 8. Come back to the car 7 hours later, temps rising by 20 degrees F and I will start the car and it will say EV 10 or 11. Depends on how much it warms up outside. 

 

That is absolutely correct, I say this all the time.  The charge level will increase if the temp rises and will decrease if the temp drops.,  Well really more like the HV battery temp rise and decline, in the end that's all that matter, and its not really the charge level but the overall pack voltage, which correlates to a charge level indication in the car.  

 

HOWEVER, when the car is turned on and you're in it, you are always drawing from the battery.  I can't see how it can go up, but I'm sure you didn't make it up.  I've never seen that with my car, that's all I can say.

 

-=>Raja.

[Pg3ibew]

That is absolutely correct, I say this all the time.  The charge level will increase if the temp rises and will decrease if the temp drops.,  Well really more like the HV battery temp rise and decline, in the end that's all that matter, and its not really the charge level but the overall pack voltage, which correlates to a charge level indication in the car.  

 

HOWEVER, when the car is turned on and you're in it, you are always drawing from the battery.  I can't see how it can go up, but I'm sure you didn't make it up.  I've never seen that with my car, that's all I can say.

 

-=>Raja.

I fully understand what you are saying. But the reason I posted here about this, is because I was astonished myself!!

[rbort]

 

I fully understand what you are saying. But the reason I posted here about this, is because I was astonished myself!!

 

 

Today I drove to Mansfield to get some dinner at Fresh Catch.  I got there with 51% battery left.  When I came out it had dropped to 46% (getting later in the evening and the outside air temperature dropping a few degrees, plus battery cooling down while sitting.

 

But you know what, I got it all wrong.  Instead of turning off the car, I should leave it on...!!   :idea: This way I could go in there and eat, and when I come out instead of having 12 miles left of range, I could have it go up to 16 miles or so.  What the heck is wrong with me, 3 1/2 years driving this car and I should have been leaving it on all the time while dining out  :headscratch:

 

Sorry couldn't resist, I'm  :hysterical:

 

-=>Raja.

[Pg3ibew]

OK, I just want to let you kids in on something here. Today, I went with my bride to the same store. Just to experiment, I stayed in the car again today. Only about 15 minutes. 

We started out with 20 miles of EV. She puts the heat on full blast mode and the heated seats. We get to the store and the EV range reads 14. The bride goes in the store. I am sitting, with the car on, in a nice sunny spot. Heated seats OFF and heat OFF. Range went UP from 14-16. 

Edited February 18, 2017 at 05:07 PM by Pg3ibew

[rbort]

Ah, now we spill some more details about the situation.

 

If you turn the heat on, the miles will drop from 16 to 14, if your turn it back off they will jump back up to 16.

 

You didn't realize this before, thought the battery came up by itself, but its because you're not using heat vs using heat.

 

The ev range miles is just an estimate.  If what you're saying is correct, then go into the battery charge level screen on the MFT and check charge level, see if when you get to the store you have 60% charge level, and then all of a sudden it rises to 68% as you sit in the car with it on.

 

-=>Raja.

Edited February 18, 2017 at 05:44 PM by rbort

[openair]

Yes, it is just an estimate. No one knows exactly how they calculate this estimate but things like the heater using less energy because more heat is coming from the ice or reducing your average speed from highway to city speed affect the estimate but not immediately like turning the heater completely off does. The estimate slowly updates to an increased estimated range. Implying there are some time weighted calculations. A possible outcome of both either overly complex or overly simply time weighted estimates is that when certain, often rare, conditions are met the estimate can have weird results.

Today, 11c outside, 20c inside the vehicle due to Sun. I park the vehicle turning off the ac that was blowing cool air. 20km range estimated. 68%. With it off. Go inside store. Come back out to the vehicle. 20km range estimated. 68%. Ac still off. I sit parked for 10 to 15 minutes. Ac still off. Estimated range rises to 21km. 67%.

An artifact of the calculation imo.

Edited February 19, 2017 at 08:45 PM by openair