new2meleaf
Posts: 1
Joined: Thu Oct 10, 2019 1:20 pm
Delivery Date: 10 Oct 2019

Newbie Battery Questions

Tue Oct 22, 2019 10:19 am

Hi everyone. Just picked up a new to me leaf about two weeks ago and love the car so far! It’s a 2013 SV that came with 82,200 miles and 11 battery health bars.
I did a lot of research and reading both before purchasing and since purchasing the car to determine how to take care of the battery. The problem I keep running into is the answers posted online and the recommendations by Nissan are vague. That’s kind of what I would expect from a car company, keep the recommendations vague so that no matter what, they can say you didn’t correctly follow their instructions.
So here are my main questions, the answers I found, and the questions I still have that I’d love everyone’s help with:

1. How long can you leave your Leaf charged at 100%?
a. Nissan says not to charge to 100% and then let the battery sit fully charged for a long time. Ok, so how long is a long time? 5 hours? 24 hours? A week? A month?
b. If sitting at 100% is bad for the battery, is the negative impact cumulative or does it “reset” each time the battery is used and then recharged? For example, if my car sits 100% charged for 6 hours a day every day for a year, that’s equivalent time wise to 89 days at 100% charge. Is the every day 6 hours just as bad for the car as 3 months sitting at 100%?

2. How low can you let the battery go before it’s a problem?
a. I will never let the car get all the way to 0%, but how low can I go before it could potentially cause damage to the battery pack? I think the lowest I’ve gotten is 15%, but would running it down to 5% be a bad idea as long as I charge up fairly soon?

3. Is DCQC really that bad?
a. Ok, so according to some independent testing, it was found that only DC quick charging and standard level 2 charging are very similar when it comes to battery degradation with a small hit when using only DC quick charging.
b. It seems that the bigger issue is the heat generated during charging. No DCQC when battery temp is 7 bars or higher, maybe OK with 6 bars, 5 bars you are good.
c. Since heat increases and charging efficiency decreases the closer the battery gets to 100%, keep an eye on battery temp when DCQC and maybe avoid going over 80% DCQC when possible. Is this accurate?

LeftieBiker
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Posts: 14624
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: Newbie Battery Questions

Tue Oct 22, 2019 12:58 pm

The answer to most of your questions is "it depends on the battery (and ambient) temperature." I wouldn't leave a Leaf sitting at 100% SOC indicated for more than three hours in Summer, but have done it for most of a day in Winter. Likewise, QC only hurts if it gets the battery too hot - 7 temperature bars or more. Heat is the #1 degrador of Leaf batteries.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

johnlocke
Posts: 594
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Newbie Battery Questions

Tue Oct 22, 2019 2:20 pm

new2meleaf wrote:
Tue Oct 22, 2019 10:19 am
Hi everyone. Just picked up a new to me leaf about two weeks ago and love the car so far! It’s a 2013 SV that came with 82,200 miles and 11 battery health bars.
I did a lot of research and reading both before purchasing and since purchasing the car to determine how to take care of the battery. The problem I keep running into is the answers posted online and the recommendations by Nissan are vague. That’s kind of what I would expect from a car company, keep the recommendations vague so that no matter what, they can say you didn’t correctly follow their instructions.
So here are my main questions, the answers I found, and the questions I still have that I’d love everyone’s help with:

1. How long can you leave your Leaf charged at 100%?
a. Nissan says not to charge to 100% and then let the battery sit fully charged for a long time. Ok, so how long is a long time? 5 hours? 24 hours? A week? A month?
b. If sitting at 100% is bad for the battery, is the negative impact cumulative or does it “reset” each time the battery is used and then recharged? For example, if my car sits 100% charged for 6 hours a day every day for a year, that’s equivalent time wise to 89 days at 100% charge. Is the every day 6 hours just as bad for the car as 3 months sitting at 100%?

2. How low can you let the battery go before it’s a problem?
a. I will never let the car get all the way to 0%, but how low can I go before it could potentially cause damage to the battery pack? I think the lowest I’ve gotten is 15%, but would running it down to 5% be a bad idea as long as I charge up fairly soon?

3. Is DCQC really that bad?
a. Ok, so according to some independent testing, it was found that only DC quick charging and standard level 2 charging are very similar when it comes to battery degradation with a small hit when using only DC quick charging.
b. It seems that the bigger issue is the heat generated during charging. No DCQC when battery temp is 7 bars or higher, maybe OK with 6 bars, 5 bars you are good.
c. Since heat increases and charging efficiency decreases the closer the battery gets to 100%, keep an eye on battery temp when DCQC and maybe avoid going over 80% DCQC when possible. Is this accurate?
1. Overnight if you're able to drive it first thing in the morning as long as the weather is cool. In hot weather, try not to charge to 100%
a. 24 hours is the max I'd suggest.
b. Damage is cumulative. Long periods at full charge does more damage than short periods followed by some discharge. Try not leave the car at more than 80% for more than a few hours. Easy to say but harder to do in practice.

2. Discharging down to LBW shouldn't be a problem. Going down to VLBW should be avoided although It probably doesn't do much damage either. Below VLBW should be avoided just for safety's sake. I'd charge anytime I got below 35% and would try to stay over 20% just as a rule of thumb.

3. The effects of DCQC are minimal. After all, you are only charging at a 2 C rate. Try to avoid it in hot weather though. Leaf batteries are slow to cool and heat is the enemy. Warming the battery by 10-15 degrees on a cool day isn't a problem but on a hot day where the battery starts out at 95-100 degrees and ends at 115-120 degrees could be.

DCQC charge rate drops as the charge hits 80-85% so the last bit of charge will probably cost more to get if you're being charged by the minute. Unless you really need the range, stop at 80-90%. Also keep in mind that the temp bars are wildly variable and each bar can vary at what temperature it shows up. Get LeafSpy so you can get accurate temps.

Hope this helps.
2016 SV, New battery at 45K mi.
Jamul, CA
San Diego East County

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Nubo
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Re: Newbie Battery Questions

Tue Oct 22, 2019 2:43 pm

All battery degradation is cumulative. And you won't get definitive answers to effects because of the number of interrelated variables. It seems from evidence presented over time that heat is the largest factor.

Your course of action depends on how much time and inconvenience you're willing to spend to mitigate battery aging. Five years into my 2nd LEAF I'm pretty much of a mind that "just drive it" suffices. I charge to 100% most of the time and sometimes it sits for days. I like having the car as ready as it can be in case I need to use it. Mine is a 2015, 24 kWh pack. As packs get larger, the inconvenience factor of under-charging is lessened. If I had a 40 kWh pack, for example I might endeavor to charge at 80% most of the time. In fact I did so with the 2012 religiously because the timer had a provision to do that easily. Ironically, despite the coddling the degradation of my 2012 was far worse than it has been with the 2015 -- reinforcing my "just drive it" mentality.
I noticed you're still working with polymers.

Lothsahn
Posts: 621
Joined: Thu Apr 05, 2018 4:35 pm
Delivery Date: 04 Jan 2018
Leaf Number: 007797

Re: Newbie Battery Questions

Tue Oct 22, 2019 9:50 pm

Nubo wrote:
Tue Oct 22, 2019 2:43 pm
All battery degradation is cumulative. And you won't get definitive answers to effects because of the number of interrelated variables. It seems from evidence presented over time that heat is the largest factor.

Your course of action depends on how much time and inconvenience you're willing to spend to mitigate battery aging. Five years into my 2nd LEAF I'm pretty much of a mind that "just drive it" suffices. I charge to 100% most of the time and sometimes it sits for days. I like having the car as ready as it can be in case I need to use it. Mine is a 2015, 24 kWh pack. As packs get larger, the inconvenience factor of under-charging is lessened. If I had a 40 kWh pack, for example I might endeavor to charge at 80% most of the time. In fact I did so with the 2012 religiously because the timer had a provision to do that easily. Ironically, despite the coddling the degradation of my 2012 was far worse than it has been with the 2015 -- reinforcing my "just drive it" mentality.
Well, the 2012 chemistry was WAY WAY worse than the 2015 chemistry. Having had both chemistries (in my 2011), I can say that charging to 80% spring/summer/fall, storing the car in an air conditioned garage, and avoiding quick charging kept my degradation minimal. In the winter, we did charge to 100% (because cold minimizes battery breakdown and we needed the extra range).

Doing the above, degradation has been <3%/yr, even in the 2011 chemistry (which was at 57% when I bought the car).
2011 Silver SV, purchased 2018, lives in Missouri (previously in CA)
LeafSpy Pro + BAFX Products OBDII dongle
Battery swap 2019/04/24 (87% SOH, 12 bar)

Gospelman
Posts: 9
Joined: Sat Oct 12, 2019 5:09 am
Delivery Date: 12 Oct 2019
Leaf Number: 015746
Location: Lee-on-the-Solent, England

Re: Newbie Battery Questions

Wed Oct 23, 2019 9:56 am

Another Newbie here with a battery degradation question. I've owned my Leaf for just 3 weeks and am delighted with it, coupla days ago I started using LeafSpy Pro and this informed me that my battery's SOH is 83.57%. The car is 5 years old, has travelled 18,500 miles and Spy also informs me that in its life the battery has received 12 QCs and 796 L1/L2s. The climate where I live South Coast England is relatively cool, so what on earth has the previous owner likely to have done to have caused this amount of degradation in so relatively short a time?
Many thanks for any replies.

LeftieBiker
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Re: Newbie Battery Questions

Wed Oct 23, 2019 11:32 am

Gospelman wrote:
Wed Oct 23, 2019 9:56 am
Another Newbie here with a battery degradation question. I've owned my Leaf for just 3 weeks and am delighted with it, coupla days ago I started using LeafSpy Pro and this informed me that my battery's SOH is 83.57%. The car is 5 years old, has travelled 18,500 miles and Spy also informs me that in its life the battery has received 12 QCs and 796 L1/L2s. The climate where I live South Coast England is relatively cool, so what on earth has the previous owner likely to have done to have caused this amount of degradation in so relatively short a time?
Many thanks for any replies.
What year is the car? If it's a 2011-2012 Leaf (unlikely if 5 years old, I guess!), then it has a battery chemistry that degrades easily, albeit more slowly in cool climates. I don't know when the switch to a better chemistry occurred in UK Leafs - it was in April of 2013 in the US and Canada. Still, leaving any Leaf at 100% charge for long periods, especially in hot weather, will degrade the battery. So will quick charging it when the battery is already hot.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

Gospelman
Posts: 9
Joined: Sat Oct 12, 2019 5:09 am
Delivery Date: 12 Oct 2019
Leaf Number: 015746
Location: Lee-on-the-Solent, England

Re: Newbie Battery Questions

Wed Oct 23, 2019 12:20 pm

Many thanks for your swift response. My car was registered new in June 2014 so there's a possibility that it might have the earlier defective chemistry, especially if it had been standing in storage for any length of time. A build date would be useful here. I think we can discount quick charging woes, as it's only had 12 QC's in its life, but your comment on keeping the battery at 100% charge for long periods might well be the reason, especially as the previous owner may have been paranoid about range & keeping the battery fully charged. I don't know who the previous owner is, as the Data Protection Act in the UK forbids the relevant Motor Licensing Authorities disclosing this information to a new owner. I only know that he/she lives in the same town as me because they forgot to clear the memory in the Sat Nav system, a procedure always to be recommended when selling a motor vehicle.

johnlocke
Posts: 594
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Newbie Battery Questions

Wed Oct 23, 2019 2:31 pm

Gospelman wrote:
Wed Oct 23, 2019 12:20 pm
Many thanks for your swift response. My car was registered new in June 2014 so there's a possibility that it might have the earlier defective chemistry, especially if it had been standing in storage for any length of time. A build date would be useful here. I think we can discount quick charging woes, as it's only had 12 QC's in its life, but your comment on keeping the battery at 100% charge for long periods might well be the reason, especially as the previous owner may have been paranoid about range & keeping the battery fully charged. I don't know who the previous owner is, as the Data Protection Act in the UK forbids the relevant Motor Licensing Authorities disclosing this information to a new owner. I only know that he/she lives in the same town as me because they forgot to clear the memory in the Sat Nav system, a procedure always to be recommended when selling a motor vehicle.
Check the manufacturer's plate in the door frame. It should have the manufacture date on it. Your car is 5 years old so 83% isn't terrible. With 796 L2 charges and 18000 mi. the car was charged every 22 mi. on average. That battery has probably never been below 60% charge and sat with a full charge most of the time. I'd suggest using the battery a little harder and charging when you get down to 30% or less. Unless you need more range the next day, I'd let it sit at a partial charge.
2016 SV, New battery at 45K mi.
Jamul, CA
San Diego East County

Gospelman
Posts: 9
Joined: Sat Oct 12, 2019 5:09 am
Delivery Date: 12 Oct 2019
Leaf Number: 015746
Location: Lee-on-the-Solent, England

Re: Newbie Battery Questions

Wed Oct 23, 2019 10:58 pm

johnlocke thanks for the information concerning build date. You'll be pleased to know that I'm already complying with your recommendations, charging to 80% and allowing the charge to sink to 20 - 30 % before recharging.

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