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Old 9th March 2020, 21:28   #31
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Default Re: Some technical questions on Electric Vehicles

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Originally Posted by avi_swift View Post
Doing this might be harmful for your phone's battery. I don't know which brand's phone you use but Apple clearly states that when storing a phone, the battery should be charged only till 50%, neither 100% nor zero. I assume this rule will remain true for other brands as well. Granted this article talks about 'long term', but since you are seeing around 30% drop when you restart after 7 or more days, I believe it will be best if you charge it only till 50% while storing.

Can anyone please clarify if EV batteries should also be half charged when the car will remain unused for a long time?
I do not full-charge my cellphone and turn off, as a matter of practice. It only happened once by accident and when I turned on after a week, 25-30 per cent charge was gone. After this, I deliberately tried one more time just to see and the result was the same.

Hence, my question if EV batteries also behave this way. And, my question was answered in affirmative. I don't see any reason why your EV can't be full-charged if you're planning to keep it unused for long periods of time. It will lose some of the charge anyway, as it happens even in Tesla.
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Old 9th March 2020, 23:08   #32
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Default Re: Some technical questions on Electric Vehicles

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Originally Posted by pgsagar View Post
I do not full-charge my cellphone and turn off, as a matter of practice. It only happened once by accident and when I turned on after a week, 25-30 per cent charge was gone. After this, I deliberately tried one more time just to see and the result was the same.

Hence, my question if EV batteries also behave this way. And, my question was answered in affirmative. I don't see any reason why your EV can't be full-charged if you're planning to keep it unused for long periods of time. It will lose some of the charge anyway, as it happens even in Tesla.
There are large differences in the algorithms and hardware used for a cell phone compared to a modern EV.
1. Tesla LR has 4416 cells in groups (bricks) of 46. They are all encased in the battery pack with a ton of sensors, fast charger, charge controller, pyro sensors, temp sensors, relays and the whole enchilada.
2. The battery casing is liquid cooled to control temperature. The batteries operate best at specific core temperature. There are some smarts in the way heat/cold from AC or drive train is used, but when parked the energy used is largely to maintain battery.
3. The algorithms used will take care of not discharging the 4416 individual batteries 100% and ruin it/impact it like our cell phone. The physical relays in the battery pack physically disconnect and prevent any sort of overcharging.

Cell phones are too sensitive to size and weight, there cannot be anything more than absolute basic needs to charge/work on day one in the showroom. The cell phone makers are happy if the battery dies after a year, as it equates to more sales of newer phones. Even the ones who make phones with replaceable batteries do not make new batteries for old phones.

The discharge/vampire drain that happens in a Tesla can be as a result of several connected car features and the battery temperature management kicking in while parked. The actual reasons can only be ascertained by looking at the logs that only Tesla (and some serious hackers) would be privy to. Rest is all speculation by the smart people of internet as to what caused the vampire drain.


Quote:
Originally Posted by ShivrajG View Post
How EV manufacturers are dealing with this situation? Just curious.
To put it crudely: they have upgraded and extended the AC to run all the time and maintain the battery temperature. Nissan did not do this, and their EVs suffer the most because of ambient temperature.

Last edited by GutsyGibbon : 9th March 2020 at 23:16.
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