cwerdna
Posts: 9355
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: 2019 Leaf battery overheating

Wed Jun 12, 2019 10:58 pm

lorenfb wrote:
cwerdna wrote: Just L2 charge for at least an hour and the whole PDM stack gets pretty warm. And, it gets a bit warm near the inlet, as well.



So you have been actually taking temperature measurements while L2 charging?

Sorry, no but it's easy to see for yourself. L2 charge for an hour or more even in a cool environment in the shade (e.g. concrete parking structure) or at night. While charging or shortly after it's stopped, open the hood and notice the whole PDM stack is warm (not quite hot) and warmer than body temperature and ambient temp.

You'll also notice warmth around the inlet area.
lorenfb wrote:
cwerdna wrote: You wouldn't want to dump that warm coolant into the battery pack except when the pack's too cold.


Are you inferring that's a factor for Nissan's not using part of the cooling system to also cool the battery?

Yes. Circulating coolant heated by the on-board charger would almost certainly heat the battery pack in many/most cases.

Except during hot summer days, it's rare for my '13 battery pack to hit 90 F or higher, esp. given my car has no CHAdeMO. L2 charging from say 30-ish% to 80% on my '13 Leaf doesn't heat the battery much, only a few degrees F.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

lorenfb
Posts: 2218
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: 2019 Leaf battery overheating

Thu Jun 13, 2019 4:38 am

cwerdna wrote:
lorenfb wrote:
cwerdna wrote: Just L2 charge for at least an hour and the whole PDM stack gets pretty warm. And, it gets a bit warm near the inlet, as well.



So you have been actually taking temperature measurements while L2 charging?

Sorry, no but it's easy to see for yourself. L2 charge for an hour or more even in a cool environment in the shade (e.g. concrete parking structure) or at night. While charging or shortly after it's stopped, open the hood and notice the whole PDM stack is warm (not quite hot) and warmer than body temperature and ambient temp.

You'll also notice warmth around the inlet area.
lorenfb wrote:
cwerdna wrote: You wouldn't want to dump that warm coolant into the battery pack except when the pack's too cold.


Are you inferring that's a factor for Nissan's not using part of the cooling system to also cool the battery?

Yes. Circulating coolant heated by the on-board charger would almost certainly heat the battery pack in many/most cases.


Nissan could've easily installed bypass valves, i.e. route coolant around the battery during L2. That's a non-issue for Nissan's non-use of TMS.
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F (35C), min discharge (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 25%, temp < 105F

lorenfb
Posts: 2218
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: 2019 Leaf battery overheating

Thu Jun 13, 2019 4:52 am

danrjones wrote:
lorenfb wrote:After driving my 2019 40kWh for a little over 2K miles, the battery temperature appears to be fairly predictable at about 5-10F max above
ambient under the following conditions:

1. The vehicle speed is kept to a maximum of 50-55 MPH, i.e. level terrain & slower @ higher grades.
2. No daytime charging & one charge per day at L2 max.
3. Minimum use of A/C or heat.

The above typically yields about 5-5.5 miles/kWh efficiency.


Well number 3 is out. I'm using the AC. It was 106 today. Nice idea though.


Actually, use of A/C will have minimum effect on raising the battery temperature compared to 1&2.
You have LeafSpy, just evaluate the battery temperature with & without A/C as you drive.
A/C consumes about 4/8 kW, that's about 10/20 battery amps. Battery power is (20^2 X .05 ohms) only 20 watts,
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F (35C), min discharge (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 25%, temp < 105F

danrjones
Posts: 107
Joined: Wed Apr 17, 2019 8:02 am
Delivery Date: 17 Jun 2019
Location: Ridgecrest, CA

Re: 2019 Leaf battery overheating

Thu Jun 13, 2019 7:27 am

Data:

No charge overnight:

Sunset temps: 100.9 max 97.9 min
6am: 92.0 max 89.4 min

Charge from 3am to 5am Lvl 2 (42 to 76% SOH)

Sunset Temps: 101.8 max 100.0 min
6am: 94.4 max 89.6 min

So with this one data point it appears the 2 hour level 2 charge did not drastically change my temps compared to a non charging the night before.
The car was slightly warmer at sunset from a hotter day and so it was slightly warmer the next morning, but not by much.

Based on this data, Lvl 1 charging to keep it cooler would not be needed?
2018 Leaf SV Pearl White with Tech and All Weather, Purchased New on 5/3/19

lorenfb
Posts: 2218
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: 2019 Leaf battery overheating

Thu Jun 13, 2019 7:55 am

danrjones wrote:Data:

No charge overnight:

Sunset temps: 100.9 max 97.9 min
6am: 92.0 max 89.4 min

Charge from 3am to 5am Lvl 2 (42 to 76% SOH)

Sunset Temps: 101.8 max 100.0 min
6am: 94.4 max 89.6 min

So with this one data point it appears the 2 hour level 2 charge did not drastically change my temps compared to a non charging the night before.
The car was slightly warmer at sunset from a hotter day and so it was slightly warmer the next morning, but not by much.

Based on this data, Lvl 1 charging to keep it cooler would not be needed?


Yes!
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F (35C), min discharge (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 25%, temp < 105F

cwerdna
Posts: 9355
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: 2019 Leaf battery overheating

Fri Jun 14, 2019 12:15 am

lorenfb wrote:Nissan could've easily installed bypass valves, i.e. route coolant around the battery during L2. That's a non-issue for Nissan's non-use of TMS.

True, but it's debatable how helpful running coolant thru the pack that will be generally no cooler than outside air temps will be, when DC FCing.

Again, there are added complexities of how to cool the modules/cells w/coolant that's fed into the pack. Examples below:
https://media.gm.com/media/us/en/chevro ... ttery.html
https://gm-volt.com/2013/08/02/spark-ev ... t-battery/

Also, I stumbled across http://www.mychevroletvolt.com/chevy-vo ... algorithms about operating temps of the various systems on separate loops on the Volt.

'19 Bolt Premier
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

lorenfb
Posts: 2218
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

Re: 2019 Leaf battery overheating

Fri Jun 14, 2019 8:12 am

cwerdna wrote:
lorenfb wrote:Nissan could've easily installed bypass valves, i.e. route coolant around the battery during L2. That's a non-issue for Nissan's non-use of TMS.

True, but it's debatable how helpful running coolant thru the pack that will be generally no cooler than outside air temps will be, when DC FCing.

Again, there are added complexities of how to cool the modules/cells w/coolant that's fed into the pack. Examples below:
https://media.gm.com/media/us/en/chevro ... ttery.html
https://gm-volt.com/2013/08/02/spark-ev ... t-battery/

Also, I stumbled across http://www.mychevroletvolt.com/chevy-vo ... algorithms about operating temps of the various systems on separate loops on the Volt.


Oh OK, so no point to TMS, right? So Tesla and others that use TMS should have followed Nissan. Got it.

Actually, given the Leaf battery's high thermal resistance to ambient, the battery's temp can be reduced below ambient with active cooling.
Remember, a vehicle's interior temp can be reduced below ambient with A/C, e.g. compress freon and then allow it to expand.
#1 Leaf SL MY 9/13: 74K miles, 48 Ahrs, 5.2 miles/kWh (average), Hx=70, SOH=78, L2 - 100% > 1000, temp < 95F (35C), min discharge (DOD) > 20 Ahrs
#2 Leaf SL MY 12/18: 115 Ahrs, 5.5 miles/kWh (average), Hx=98, SOH=99, DOD > 25%, temp < 105F

metricus
Posts: 94
Joined: Wed May 15, 2019 1:51 pm
Delivery Date: 28 Apr 2019
Leaf Number: 307046
Location: Reading, PA

Re: 2019 Leaf battery overheating

Fri Jun 14, 2019 1:26 pm

lorenfb wrote:After driving my 2019 40kWh for a little over 2K miles, the battery temperature appears to be fairly predictable at about 5-10F max above
ambient under the following conditions:

1. The vehicle speed is kept to a maximum of 50-55 MPH, i.e. level terrain & slower @ higher grades.
2. No daytime charging & one charge per day at L2 max.
3. Minimum use of A/C or heat.

The above typically yields about 5-5.5 miles/kWh efficiency.


I noticed something similar. At low highway speeds the battery does loose heat although very slow. I also DC charged and after jumping to 41C it returned eventually to 35C while OT was 24C and night time.

However if I drive at turnpike speeds 120 km/h - 70 mph and DC charge I go on red as per OP.

So the conditions for achieving a thermal balance are pretty drastic IMHO. Even so, DC charging at 35C results in a charge power of about 24 kW which sucks big time.

GerryAZ
Gold Member
Posts: 2154
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: 2019 Leaf battery overheating

Fri Jun 14, 2019 6:46 pm

Liquid coolant from radiator cannot cool a battery below ambient temperature. Active cooling using a refrigeration process (air conditioning compressor, for example) is necessary if it is desired to cool a battery during summer. I had ambient temperature of 112 F on Wednesday evening in the shade--radiator coolant circulation through the battery would not help. On the other hand, the onboard charger gets hot enough to warm the radiator enough to cause the fans to turn on once in a while so liquid cooling with radiator is suitable for the power electronics.
Last edited by GerryAZ on Sat Jun 15, 2019 2:39 am, edited 1 time in total.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

danrjones
Posts: 107
Joined: Wed Apr 17, 2019 8:02 am
Delivery Date: 17 Jun 2019
Location: Ridgecrest, CA

Re: 2019 Leaf battery overheating

Fri Jun 14, 2019 8:39 pm

Yesterday AM my SOH 97.42%

Tonight it is 96.49%

That's basically one full percent in 30 hours or so.

At this rate I'll get a free battery by the end of next week. Lol

I really wonder in hot climates if Nissan gave us too much warranty. I have ten years to hit 70%?
2018 Leaf SV Pearl White with Tech and All Weather, Purchased New on 5/3/19

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