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TonyWilliams
Posts: 10091
Joined: Sat Feb 19, 2011 1:48 am
Location: San Diego
Contact: Website

Re: Turning Over a New LEAF: My Response to a Lost Capacity

Wed Jul 18, 2012 7:11 am

turbo2ltr wrote:
I haven't looked at his data, but as far as I'm concerned, any increase as it got cooler wasn't a "seasonal winter increase" it was a "recovery from a summer decrease".

All I know:
Hot temperatures reduces the ability of the battery to store a charge.
My car did NOT charge to 280 for the first couple months. I am quite sure I remember others reporting this as well.

I'll leave the speculation up to you.
I have observed this with my new 2012 LEAF. With battery at "full" charge when at moderate temps, it would hold 278-280 Gids (I have never actually seen 281, but other drivers did on my car).

When the battery became hot, at over 130F, it would only hold about 255-260 Gid. Once the temp returned to "normal" that same day, it would hold 278-280 Gid again.

DaveinOlyWA
Posts: 15053
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Turning Over a New LEAF: My Response to a Lost Capacity

Wed Jul 18, 2012 9:23 am

TonyWilliams wrote:
turbo2ltr wrote:
I haven't looked at his data, but as far as I'm concerned, any increase as it got cooler wasn't a "seasonal winter increase" it was a "recovery from a summer decrease".

All I know:
Hot temperatures reduces the ability of the battery to store a charge.
My car did NOT charge to 280 for the first couple months. I am quite sure I remember others reporting this as well.

I'll leave the speculation up to you.
I have observed this with my new 2012 LEAF. With battery at "full" charge when at moderate temps, it would hold 278-280 Gids (I have never actually seen 281, but other drivers did on my car).

When the battery became hot, at over 130F, it would only hold about 255-260 Gid. Once the temp returned to "normal" that same day, it would hold 278-280 Gid again.
so AZ owners might be jumping the gun a bit... still makes the car non functional. sucks. i go from about 85-87 miles (more or less) in summer to 70-72 miles in winter (very little CC on this. wear a coat!! wont kill ya) but that is the price of rice. i knew that. so in 3-4 years i will start having issues in winter that AZ'rs are experiencing now.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 13,705 mi, 93.41% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

SanDust
Posts: 1363
Joined: Fri Aug 06, 2010 10:54 am

Re: Turning Over a New LEAF: My Response to a Lost Capacity

Wed Jul 18, 2012 10:22 am

TonyWilliams wrote:
turbo2ltr wrote:
I haven't looked at his data, but as far as I'm concerned, any increase as it got cooler wasn't a "seasonal winter increase" it was a "recovery from a summer decrease".

All I know:
Hot temperatures reduces the ability of the battery to store a charge.
My car did NOT charge to 280 for the first couple months. I am quite sure I remember others reporting this as well.

I'll leave the speculation up to you.
I have observed this with my new 2012 LEAF. With battery at "full" charge when at moderate temps, it would hold 278-280 Gids (I have never actually seen 281, but other drivers did on my car).

When the battery became hot, at over 130F, it would only hold about 255-260 Gid. Once the temp returned to "normal" that same day, it would hold 278-280 Gid again.
Interesting observations. A battery cell can absorb more energy when hot and, once, you've lost battery capacity you can't recover it (for example, once the Li ions have moved from the electrolyte to the anode you can't get them back into play). Based on temperature, the charger may be dialing back the to avoid side reactions and charging more fully when the temperature drops, but you're not "recovering" capacity as cooler temperatures return.

If the capacity bars are linked to charging which is dependent on temperature, then as temperatures cool one or more of the capacity bars may return. However, if the capacity bars truly represent capacity then that won't happen.

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DaveEV
Posts: 6246
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: Turning Over a New LEAF: My Response to a Lost Capacity

Wed Jul 18, 2012 10:37 am

TonyWilliams wrote:I have observed this with my new 2012 LEAF. With battery at "full" charge when at moderate temps, it would hold 278-280 Gids (I have never actually seen 281, but other drivers did on my car).

When the battery became hot, at over 130F, it would only hold about 255-260 Gid. Once the temp returned to "normal" that same day, it would hold 278-280 Gid again.
Another reason to perform actual range tests to confirm GID readings. Were you able to check 100% charge voltage when the battery was hot? Did it still reach ~394V as expected?

The question is: Is the reduction in GID count when the battery is hot reflects an actual reduction in usable capacity (in theory because the BMS limits max or min voltage) or is simply the result of some sort of temperature correction applied to the GID numbers?

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