DaveinOlyWA
Posts: 12312
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Battery temp management for new leaf

Tue Oct 10, 2017 10:46 am

Oils4AsphaultOnly wrote:
DaveinOlyWA wrote:
Oils4AsphaultOnly wrote:
I was thinking more like apt dweller who can now consider a leaf, because they can fast charge once a week while grocery shopping. QC'ing isn't just to make a long distance trip.


not sure there is any evidence that shows short duration heat being a significant cause of degradation. if it was, I would have lost about 7-8 bars by now! Been in the red a few dozen times but been at 9-10 TBs "at least" 100 times....


But the apt dweller with his 40kwh leaf QC'ing during grocery shopping, isn't doing a short-duration charge. This would be his weekly charge from 20% to 90%, because he doesn't have charging at home. This use case is most definitely long-duration QC.

Edit: By the way, 150 mile range isn't comatose driving, that's a 2-hr trip to san diego or to visit friends for a day. A QC will be needed for the return trip in case there's no L2 at the destination.


The "comatose" comment has to do with the LEAF, not the driver.

As far as a monster charging session once a week? hmmm, I think your gas roots are starting to show :)
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Oils4AsphaultOnly
Gold Member
Posts: 275
Joined: Sat Oct 10, 2015 4:09 pm
Delivery Date: 20 Nov 2016
Leaf Number: 313890
Location: Arcadia, CA

Re: Battery temp management for new leaf

Tue Oct 10, 2017 10:50 am

DaveinOlyWA wrote:
Oils4AsphaultOnly wrote:
DaveinOlyWA wrote:
not sure there is any evidence that shows short duration heat being a significant cause of degradation. if it was, I would have lost about 7-8 bars by now! Been in the red a few dozen times but been at 9-10 TBs "at least" 100 times....


But the apt dweller with his 40kwh leaf QC'ing during grocery shopping, isn't doing a short-duration charge. This would be his weekly charge from 20% to 90%, because he doesn't have charging at home. This use case is most definitely long-duration QC.

Edit: By the way, 150 mile range isn't comatose driving, that's a 2-hr trip to san diego or to visit friends for a day. A QC will be needed for the return trip in case there's no L2 at the destination.


The "comatose" comment has to do with the LEAF, not the driver.

As far as a monster charging session once a week? hmmm, I think your gas roots are starting to show :)


And I think you're failing to account for the change in use-cases as the customer pool expands. How else would you see an apt dweller charge if they don't have home/work charging and still want to get an EV? There isn't an L2 charger in every parking lot yet.
[2013 leaf traded for 2016 leaf S30:
build date: Sep '16 :: purchased: Nov '16
1 May 2017 - 7300 miles & 363 GIDs
6 Sep 2017 - 13k miles & 359 GIDs
26 Oct 2017 - 15.5k miles & 344 GIDs
26 Nov 2017 - 17.1k miles & 332 GIDs]

DaveinOlyWA
Posts: 12312
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Battery temp management for new leaf

Tue Oct 10, 2017 11:11 am

Oils4AsphaultOnly wrote:
DaveinOlyWA wrote:
Oils4AsphaultOnly wrote:
But the apt dweller with his 40kwh leaf QC'ing during grocery shopping, isn't doing a short-duration charge. This would be his weekly charge from 20% to 90%, because he doesn't have charging at home. This use case is most definitely long-duration QC.

Edit: By the way, 150 mile range isn't comatose driving, that's a 2-hr trip to san diego or to visit friends for a day. A QC will be needed for the return trip in case there's no L2 at the destination.


The "comatose" comment has to do with the LEAF, not the driver.

As far as a monster charging session once a week? hmmm, I think your gas roots are starting to show :)


And I think you're failing to account for the change in use-cases as the customer pool expands. How else would you see an apt dweller charge if they don't have home/work charging and still want to get an EV? There isn't an L2 charger in every parking lot yet.


I would imagine that they would have to charge MUCH more often. Sure its conceivable that they live 10 miles from work and don't have much of a life so they don't need much more than 200 miles a week but even if that was the case, I still can't see the logic of charging for at least an hour when opportunity charging is available to simply grab enough to insure you have a day or two's worth.

But then again, I am a different shopper. I always use self check out for one and rarely in the building for 30 mins.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Oils4AsphaultOnly
Gold Member
Posts: 275
Joined: Sat Oct 10, 2015 4:09 pm
Delivery Date: 20 Nov 2016
Leaf Number: 313890
Location: Arcadia, CA

Re: Battery temp management for new leaf

Tue Oct 10, 2017 11:32 am

DaveinOlyWA wrote:
Oils4AsphaultOnly wrote:
DaveinOlyWA wrote:
The "comatose" comment has to do with the LEAF, not the driver.

As far as a monster charging session once a week? hmmm, I think your gas roots are starting to show :)


And I think you're failing to account for the change in use-cases as the customer pool expands. How else would you see an apt dweller charge if they don't have home/work charging and still want to get an EV? There isn't an L2 charger in every parking lot yet.


I would imagine that they would have to charge MUCH more often. Sure its conceivable that they live 10 miles from work and don't have much of a life so they don't need much more than 200 miles a week but even if that was the case, I still can't see the logic of charging for at least an hour when opportunity charging is available to simply grab enough to insure you have a day or two's worth.

But then again, I am a different shopper. I always use self check out for one and rarely in the building for 30 mins.


That's the difference right there I think. The cities around here aren't full of chargers everywhere. Opportunity charging is also dependent on the driver's lifestyle.

My co-worker lives in an apt and he desperately wants to dump his prius, he commutes ~15 miles each way per day. A few days charge for him would be ~25kwh, which means the 40kwh is almost a viable option for him (cost of the charge is the remaining issue). There's a large untapped pool of future EV owners out there, and what works for us charge@home types won't work for them.
[2013 leaf traded for 2016 leaf S30:
build date: Sep '16 :: purchased: Nov '16
1 May 2017 - 7300 miles & 363 GIDs
6 Sep 2017 - 13k miles & 359 GIDs
26 Oct 2017 - 15.5k miles & 344 GIDs
26 Nov 2017 - 17.1k miles & 332 GIDs]

DaveinOlyWA
Posts: 12312
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Battery temp management for new leaf

Tue Oct 10, 2017 11:38 am

Well, EVs are not going away so we will have MUCH more charging options or an all out war...

The ideology that long range EVs removes the need for public charging is completely wrong. Public charging only allows opportunity charging to cover more transportation options.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 27,000 miles.363GID Ahr 79.13Hx95.17%kwh28.1QCs238,L2's 251
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

johnlocke
Posts: 178
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Battery temp management for new leaf

Tue Oct 10, 2017 12:47 pm

Here's why you are going to want/need an active TMS. All this talk about the internal resistance started me to wondering about what are the actual losses while driving and charging. Assuming 60 mph and 16 KWH per hour, that works out to 42 amps current across the internal resistance. 42*42*.115 = 202 watts internal loss. About 650 BTU's an hour. However if we are charging at a level 2 that's only 16,5 amps at 400 VDC. 16*16*.115 = about 32 watts internal loss or about 100 BTU's per hour. That's pretty negligible in my opinion. What happens when we DCFC at 40KW? I typically see 106 amps while fast charging. 106*106*.115 = 1292 watts or around 4000 BTU's per hour. Quite a difference there. What happens if we upgrade to 100KW charging so we can charge our 60 KWH 2019 Leaf in 30-40 minutes? Now we're talking 250 amps at 400 VDC. If we assume no changes to the internal resistance then we are looking at 7200 W loss and 25000 BTU'S an hour. Even if you can somehow cut the internal resistance by 75% you are still looking at 6000 BTU's an hour and that kind of reduction isn't likely. If you want to charge at high rates you are going to have to cool the battery somehow.

You can quibble over what the actual values are for internal resistance. The fact remains that fast charging will generate a lot of heat and if you can't get rid of it, you will cook the battery. Larger batteries make the situation worse simply because higher currents are necessary to keep the charge time reasonable. If you can park your car overnight while charging, you might not need TMS for that. Of course, that might not be viable in Phoenix or Dallas or even east county San Diego. It appears that months of high temps take a toll in any case. Since Tesla's don't seem to have this problem, either the battery chemistry is better or active cooling works or both.
2016 SV
Jamul, CA
San Diego East County

johnlocke
Posts: 178
Joined: Fri Jan 08, 2016 3:47 pm
Delivery Date: 14 Dec 2015
Leaf Number: 300582

Re: Battery temp management for new leaf

Wed Oct 11, 2017 8:12 am

Just out of curiosity, I checked my battery temps before and after L2 charging. Battery temp before charging was 81 degrees and after 3 hours charging ( 24%-100%) it was 85 degrees. Ambient at start was 81 degrees at start and 87 degrees at the end. the battery didn't generate enough heat to even keep up with the change in ambient temps. If I get the chance I'll try to repeat this with a DCFC just to see what the difference is. I know that it will add a couple of bars to the temp gauge but that is so inaccurate that it's next to meaningless. I've always wondered why they didn't assign fixed increments to the temp gauge rather than the overlapping ranges they use. Or even better a digital readout! For Christ's sake, it's an electric car with a screen in place of the gauges, Why not just give me the facts instead of guess-o-meter gauges with simulated analog readouts.
2016 SV
Jamul, CA
San Diego East County

SageBrush
Posts: 1482
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery temp management for new leaf

Wed Oct 11, 2017 8:17 am

johnlocke wrote:Just out of curiosity, I checked my battery temps before and after L2 charging. Battery temp before charging was 81 degrees and after 3 hours charging ( 24%-100%) it was 85 degrees. Ambient at start was 81 degrees at start and 87 degrees at the end. the battery didn't generate enough heat to even keep up with the change in ambient temps. If I get the chance I'll try to repeat this with a DCFC just to see what the difference is.

It would also be interesting to know how much the battery heats up in those conditions without any charge.
I'll guess very little -- perhaps a degree.

That is the battery heat capacity in play, but it also means that cool-down is slow
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

SageBrush
Posts: 1482
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery temp management for new leaf

Wed Oct 11, 2017 8:34 am

johnlocke wrote:It appears that months of high temps take a toll in any case. Since Tesla's don't seem to have this problem, either the battery chemistry is better or active cooling works or both.
I gather that the Volt uses battery and a chemistry very similar to the LEAF albeit with a TMS, and has not been associated with much if any range loss.

There are some five people left outside of Nissan who are skeptical of the utility of a good TMS, but for everyone else the debate is over. And frankly, I expect those five to become fierce TMS advocates the day that Nissan includes one in their EVs
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

lorenfb
Posts: 1405
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: Battery temp management for new leaf

Wed Oct 11, 2017 8:38 am

SageBrush wrote:
johnlocke wrote:Just out of curiosity, I checked my battery temps before and after L2 charging. Battery temp before charging was 81 degrees and after 3 hours charging ( 24%-100%) it was 85 degrees. Ambient at start was 81 degrees at start and 87 degrees at the end. the battery didn't generate enough heat to even keep up with the change in ambient temps. If I get the chance I'll try to repeat this with a DCFC just to see what the difference is.

It would also be interesting to know how much the battery heats up in those conditions without any charge.
I'll guess very little -- perhaps a degree.

That is the battery heat capacity in play, but it also means that cool-down is slow


You both need to use LeafSpy and not guess or rely on cluster bars graphs, and/or indicate data measurement source.

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