LeftieBiker
Posts: 6810
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: Battery temp management for new leaf

Mon Aug 28, 2017 4:56 pm

The Volt is a HYBRID (with a bigger battery than any hybrid). That car will use the battery only mode as a gimmick, and then go to gasoline operation when it feels like it, to save the battery and not discharge it to any great extent in order to keep the number of discharge cycles low. I personally have a 12 year old Hybrid, and it still works find. So this car doesn't count.


Inaccurate facts and faulty reasoning. The Volt works fine in "battery mode" for many people. Just as with TMS, it depends on how you need to use the car. The only reason I don't consider the Volt is the cabin design.
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.

Durandal
Posts: 305
Joined: Wed Sep 21, 2016 8:55 am
Delivery Date: 22 Sep 2016
Leaf Number: 025018
Location: Central Arkansas

Re: Battery temp management for new leaf

Tue Aug 29, 2017 6:41 am

Your car only takes a range hit from when you use the air conditioning. Any range hit from simply HAVING the air conditioning is negligible... As such, those in temperate environments will only have their battery ATM turn on when quick charging and in really hot summers. Is that such a problem? How about I whine and complain that my Leaf has a battery heater when I never need it for my hot climate? No, I don't, because it doesn't bother me, because it doesn't turn on. It makes sense for people to be upset at the Leaf NOT having battery ATM when their batteries crap out early, but it makes absolutely NO sense for people in temperate climates to complain about the idea of the Leaf having battery ATM.
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf, and a Tesla Model 3 reservation expected to receive in June 2018.

lorenfb
Posts: 1258
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

Tue Aug 29, 2017 9:07 am

Durandal wrote:Your car only takes a range hit from when you use the air conditioning. Any range hit from simply HAVING the air conditioning is negligible... As such, those in temperate environments will only have their battery ATM turn on when quick charging and in really hot summers. Is that such a problem? How about I whine and complain that my Leaf has a battery heater when I never need it for my hot climate? No, I don't, because it doesn't bother me, because it doesn't turn on. It makes sense for people to be upset at the Leaf NOT having battery ATM when their batteries crap out early, but it makes absolutely NO sense for people in temperate climates to complain about the idea of the Leaf having battery ATM.


The problem, though, is that a BEV's battery has a high thermal mass basically requiring the ATM system
to always be active, i.e. a BEV's battery has a very long thermal time constant which would require increasingly
more battery power the narrower the desired temperature band. It's not like pushing the AC button and having
the interior cool within minutes.

Durandal
Posts: 305
Joined: Wed Sep 21, 2016 8:55 am
Delivery Date: 22 Sep 2016
Leaf Number: 025018
Location: Central Arkansas

Re: Battery temp management for new leaf

Tue Aug 29, 2017 11:42 am

lorenfb wrote:The problem, though, is that a BEV's battery has a high thermal mass basically requiring the ATM system
to always be active, i.e. a BEV's battery has a very long thermal time constant which would require increasingly
more battery power the narrower the desired temperature band. It's not like pushing the AC button and having
the interior cool within minutes.

You're not trying to keep the battery from hitting 80F, you're trying to keep it from hitting 100F+ while charging or discharging. In winter times, the battery won't see those temperatures, and the damage is more done when charging/discharging at high temperatures. So if it activates as soon as you start doing a DC fast charge, it can prevent the temperatures from hitting those damaging levels while doing a bunch of nothing when you're driving around in town.

In any event, I'd rather have an intermittent energy penalty of 300w-500w continuous and have a traction battery that gets an extra year or two of longevity than to save that 300w-500w of usage and have a vehicle that is less than practical after 7 years time.
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf, and a Tesla Model 3 reservation expected to receive in June 2018.

lorenfb
Posts: 1258
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 Aug 30, 2017 8:53 am

Durandal wrote:
In any event, I'd rather have an intermittent energy penalty of 300w-500w continuous and have a traction battery that gets an extra year or two of longevity than to save that 300w-500w of usage and have a vehicle that is less than practical after 7 years time.


That's your guess on the power 'hit'! Do have a design for a proposed system that Nissan can use?
If one uses your worst case number (500W) and 24 hr 'on' time in some climates, that's about 12 kWh of energy per day.
Obviously, a good portion of that energy would be supplied when connected for charging.

Durandal
Posts: 305
Joined: Wed Sep 21, 2016 8:55 am
Delivery Date: 22 Sep 2016
Leaf Number: 025018
Location: Central Arkansas

Re: Battery temp management for new leaf

Thu Aug 31, 2017 6:32 am

lorenfb wrote:
Durandal wrote:
In any event, I'd rather have an intermittent energy penalty of 300w-500w continuous and have a traction battery that gets an extra year or two of longevity than to save that 300w-500w of usage and have a vehicle that is less than practical after 7 years time.


That's your guess on the power 'hit'! Do have a design for a proposed system that Nissan can use?
If one uses your worst case number (500W) and 24 hr 'on' time in some climates, that's about 12 kWh of energy per day.
Obviously, a good portion of that energy would be supplied when connected for charging.

Do you have some snark that Nissan can use? If you read my bloody original message, I suggested ATM that would only be used when discharging or charging the battery, which is when more of the heat damage would be done versus when it's sitting idle. It's ridiculous to suggest that such a system would run 24 hours a day.
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf, and a Tesla Model 3 reservation expected to receive in June 2018.

Durandal
Posts: 305
Joined: Wed Sep 21, 2016 8:55 am
Delivery Date: 22 Sep 2016
Leaf Number: 025018
Location: Central Arkansas

Re: Battery temp management for new leaf

Thu Aug 31, 2017 6:40 am

Here's some reading material for you. Enjoy.
http://publications.lib.chalmers.se/rec ... 200046.pdf
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf, and a Tesla Model 3 reservation expected to receive in June 2018.

SageBrush
Posts: 1114
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Battery temp management for new leaf

Thu Aug 31, 2017 7:31 am

Durandal wrote:Here's some reading material for you. Enjoy.
http://publications.lib.chalmers.se/rec ... 200046.pdf


Nice article, thanks

I've wondered for a while now how much energy per time is released into the battery during use and charging. This data is helpful:

Image

So even during moderate acceleration there is 2 kW of heat to remove.
DC charging is going to be multiples of that amount
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

edatoakrun
Posts: 4574
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: Battery temp management for new leaf

Thu Aug 31, 2017 7:55 am

edatoakrun wrote:
...Seven years ago, The LEAF was (and still is) a far superior BEV for most buyers, for having the "better" conductive battery cooling design...

rmay635703 wrote:My 2013 volt meanwhile uses the same kwhrs to charge today 47,000 miles later as it did new.
Discharges the same 10.3kwhrs today as it did new.

This guys EV range is within the margin of error

https://www.voltstats.net/Stats/Details/1579

Maybe a battery temperature system is a good idea?

No, it's not, and neither was the Gen one Volt, as used by most of its drivers.

The primary message from that link you supplied is what an extremely poor PHEV design the gen one Volt was.

All the extra cost and complexity, all the compromises in interior and room and drivabilty, all the kWh drained from the grid, that Volt still got only ~59 miles of range from each gallon of the ~6,750 gallons gas it used, while emitting ~90,000,000 gallons of C02 just from the tailpipe.

God-only-knows how many more millions of gallons of CO2 this monstrosity produced in the production process, and in generation of electricity so inefficiently used during the ~35% of the miles driven when it was not fueled by gas.

What the Volt gen one proved is that batteries carried in a refrigerated case and acting primarily as deadweight, rather than supplying propulsion energy, will indeed last a very long time.

SO WHAT?

My LEAF, nearing the end of it's seventh (and hottest yet) baking North-Sacramento-Valley Summer, and after ~56 k gas-free miles, traveled 104.2 miles Tuesday on a single charge without even reaching the VLBW.

And also (possibly) nearing the end of my LEAF pack's first life, it still has over 50% more electric range under all conditions than any Gen one Volt did on the day of delivery.
no condition is permanent

finman100
Posts: 271
Joined: Thu Sep 20, 2012 10:42 am
Delivery Date: 06 Jun 2014
Location: Albany, OR

Re: Battery temp management for new leaf

Thu Aug 31, 2017 8:32 am

yay! one data point!
Albany, Oregon
2014 Silver SV with charge/LED package. June 2014, I'm in the EV game!
40,200 miles
18.5 kWh on 100% charge (54-ish Ah)
4.2 miles/kWh average
Best trip: all of 'em. They're all no-gas!

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