specialgreen
Posts: 20
Joined: Sun Mar 26, 2017 1:21 pm
Delivery Date: 26 Mar 2017
Location: Minnesota

when does DCQC cause degradation?

Mon Sep 25, 2017 2:43 pm

I have had my 2017 for about 3 weeks and 1k miles. So-far, I have only quick-charged it! I wait until stored energy is below 40%, then charge it to 80%. Sample of these short charges have been 11kw-hrs, 14, 6, 12, 10, 11 10, 11 kw-hrs etc. Basically, 10 minutes or so of DCQC, every other day. It's temperate where I live, so battery heat bars have been starting at 5 bars, ending charge cycle with 6; or starting at 6 bars and ending with 7... and that is during the hottest part of the year.

The manual just states to avoid DCQC to promote battery longevity. My thought was that increasing battery temp only from 5 to 6 bars, or from 6 to 7, will probably do nothing to degrade the battery. And the DCQC is free power using Nissan Good-to-Go charging program. And it lets me stop charging at 80% easily. It's also along my commute, and I clear my email while I wait, so it's not inconvenient.

But really, the total savings of using free charging for two years is only $800-$900 for me. So I'm wondering: would doing nothing but DCQC (in short charge cycles at 7 bars of heat or less) cause $800-$900 of degradation to the battery (about 15% the cost of a new battery)? For all I know, DCQC-induced degradation is cumulative and linear. Or maybe it follows a "hockey-stick" curve, causing little/no damage until you get to 9+ bars.

LeftieBiker
Posts: 6959
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: when does DCQC cause degradation?

Mon Sep 25, 2017 2:52 pm

We don't know for sure, but your guess is probably right. DCFC causes degradation by pushing pack heat above "safe" (for longevity) levels. It may even help longevity a bit at lower temps. You can help answer this question yourself!
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

specialgreen
Posts: 20
Joined: Sun Mar 26, 2017 1:21 pm
Delivery Date: 26 Mar 2017
Location: Minnesota

Re: when does DCQC cause degradation?

Tue Sep 26, 2017 8:21 am

OK, I'll be the tester for "nothing but low-temp DCQC for 2 years." If I ever sell this car, and the buyer hooks-up LeafSpy, they're going to be surprised at the QC count!

I plan to balance cells monthly, which I did last night at L2, 12 amps. I thought balancing would add hours, even at the DCQC station, so I did it at home. But looking at my power graph for last night, the L2 bulk charge finished, then there was a 25-minute tail-off of charge current, then 30 minutes containing three small 1kw spikes lasting <5 minutes each. Balancing appears to have finished 55 minutes after bulk charge completed. If balancing adds less than one hour to charge time, then I could balance cells at the DCQC station too.

alozzy
Posts: 627
Joined: Fri Jan 20, 2017 4:25 pm
Delivery Date: 18 Jan 2017
Location: Vancouver, BC
Contact: Website

Re: when does DCQC cause degradation?

Tue Sep 26, 2017 1:31 pm

Just an etiquette suggestion - if there is an L2 EVSE available, next to the DCQC, then charge your battery to 80% using the DCQC and top off your battery using the L2 instead. Unless, of course, you stay with the Leaf while it's DCQC charging so you can move it to an L2 if someone else wants to DCQC. Lots of people DCQC only when they are in a hurry or when they are long distance traveling...
Vancouver, CA owner of a 2013 Ocean Blue SV + QC, purchased 01/2017 in WA
Zencar 12/20/24/30A L1/L2 portable EVSE
1-1/4" Curt #11396 hitch
After market, DIY LED DRLs
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Loving my first BEV :D

DaveinOlyWA
Gold Member
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Leaf Number: 314199
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Re: when does DCQC cause degradation?

Tue Sep 26, 2017 1:47 pm

A Fast charge station will not balance your cells. It will simply see the pack as full and not start
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 24,858.2 miles.363 GIDAhr 80.66Hx95.95%kwh28.1QCs215,L2's 227
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

desiv
Posts: 588
Joined: Tue Jan 06, 2015 1:10 pm
Delivery Date: 04 Jan 2015
Leaf Number: 018850
Location: Lincoln City, Oregon

Re: when does DCQC cause degradation?

Tue Sep 26, 2017 2:35 pm

I wouldn't worry unless it's really hot..

I am now QCing 3 times a day for my commute (and a full L2 every night (well, work days)).
I am down to 10 bars, but it's still expected per the degradation chart per age...
2012 Leaf with 75k+ miles so far...
(I've owned it for 3 years; about 25k miles for me per year)

So no significant extra degradation (probably some, but nothing significant) from frequent QCs.

Now, I never QC to full. Only to under 80%..
And I don't charge to full and leave the car sitting for days..

The people who have had serious degradation all live in really hot climates..

I'm in the PNW, so pretty moderate.. Although there have been days with 90+ degree temps.. And I have had my car on those days.
But not too many of them...

desiv
2012 SL - Silver

LeftieBiker
Posts: 6959
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: when does DCQC cause degradation?

Tue Sep 26, 2017 2:36 pm

DaveinOlyWA wrote:A Fast charge station will not balance your cells. It will simply see the pack as full and not start


He was referring to leaving it connected after 80% is reached, not connecting it at or above 80%. Thus Alozzy's suggestion.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

DaveinOlyWA
Gold Member
Posts: 12115
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: when does DCQC cause degradation?

Tue Sep 26, 2017 2:57 pm

LeftieBiker wrote:
DaveinOlyWA wrote:A Fast charge station will not balance your cells. It will simply see the pack as full and not start


He was referring to leaving it connected after 80% is reached, not connecting it at or above 80%. Thus Alozzy's suggestion.


doesn't matter. DCFC won't do a full charge. you might get it to 95% on some stations but that is about it.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 24,858.2 miles.363 GIDAhr 80.66Hx95.95%kwh28.1QCs215,L2's 227
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

alozzy
Posts: 627
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Location: Vancouver, BC
Contact: Website

Re: when does DCQC cause degradation?

Tue Sep 26, 2017 7:41 pm

My comment was more to do with etiquette than with balanced charging. People who plugin their EV at a DCQC, then walk away for an hour, is becoming common place and it's super frustrating when you're the one waiting for the person to come back.
Vancouver, CA owner of a 2013 Ocean Blue SV + QC, purchased 01/2017 in WA
Zencar 12/20/24/30A L1/L2 portable EVSE
1-1/4" Curt #11396 hitch
After market, DIY LED DRLs
LeafSpy Pro + Konnwei KW902 ELM327 BT OBDII dongle
Loving my first BEV :D

DaveinOlyWA
Gold Member
Posts: 12115
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: when does DCQC cause degradation?

Wed Sep 27, 2017 4:26 am

At a public charging station there is an authentication process to verify access. This happens EVERY time the power is cycled. So you CANNOT balance a pack at an L2 or an L3 unless its a station that is free and always on (needs no card, smartphone access, etc.) Now L3's that are free and only require a button to be pushed will also not balance the pack.

To balance a pack, it requires multiple power on cycles.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 24,858.2 miles.363 GIDAhr 80.66Hx95.95%kwh28.1QCs215,L2's 227
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

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