Battery Temp. Gauge Reading

[iamchemist]

Would someone please fill me in on the LEAF Battery Temperature Gauge reading (the bar gauge on the left of the main display in front of the driver)? On my LEAF that gauge starts out in the middle of the (white) normal range, when the car has sat in the garage all night - i.e., the battery is surely at garage temperature of maybe 60 degrees F.

Then after driving in town for 30 min. or so that battery temp. gauge has not moved at all and is still setting exactly in the middle of the white range. So, in 30 min. of driving, the battery has not gotten measurably warmer? I don't get it??

 

[ebill3]

Usually, in town driving is not terribly demanding. Get on the freeway and travel 30 miles at max allowable speed. Ill bet the temperature rises.

Where I live, the battery usually sits at four bars and in 40°F freeway driving, I can get five bars.

Bill

 

[abasile]

Then after driving in town for 30 min. or so that battery temp. gauge has not moved at all and is still setting exactly in the middle of the white range. So, in 30 min. of driving, the battery has not gotten measurably warmer? I don't get it??

The battery temperature bars, particularly the middle ones, offer a very coarse grained view. My understanding is that, if there are five temperature bars, the pack temperature could be anywhere in the range of roughly 50-75°F. (It would be nice if we had more resolution than this, since a battery at 50°F might have as much as 10% less capacity compared if it were at 70°F.)

Also, Nissan seems to have chosen a battery chemistry that is quite thermally stable. Charging and discharging do not seem to produce a great deal of heat, though I sometimes do gain a temperature bar in response to a lot of charging/driving. Ambient temperature seems to be the most significant influencer of battery pack temperature.

 

[planet4ever]

Would someone please fill me in on the LEAF Battery Temperature Gauge reading (the bar gauge on the left of the main display in front of the driver)? On my LEAF that gauge starts out in the middle of the (white) normal range, when the car has sat in the garage all night - i.e., the battery is surely at garage temperature of maybe 60 degrees F.
Then after driving in town for 30 min. or so that battery temp. gauge has not moved at all and is still setting exactly in the middle of the white range. So, in 30 min. of driving, the battery has not gotten measurably warmer? I don't get it??

I don't get it either, but according to the service manual 5 bars can apparently represent any battery temperature from about 28°F to about 81°F. (I'm visually interpolating on a graph that shows only 18°F steps -- or 10°C, of course.) There is a huge amount of overlap, since 4 bars is shown from about 23°F to about 59°F and 6 bars from 50°F to about 101°F. They give what seems to me to be a hand-waving explanation that the number of bars shown is adjusted based on long-term decrease in battery capacity.

Ray

 

[TonyWilliams]

The fifth battery temp bar is good for 50F to 74F, and the sixth is 74F up to about 100F.

Not a lot of movement for 50F total of temp change.

EDIT: but what Ray says about the service manual is true too.

 

[smkettner]

For me:

5 bars = winter, 6 bars = summer. Have not seen any higher or lower. Battery heat is basically a non-issue.

 

[ENIAC]

I've never seen it change, even after driving over 60 miles on the highway. I'm interested to see what QC from very low to 80% does.

 

[garygid]

Each of the Pack Temperature Bars 4, 5, 6, and 7 cover 24ºF, with Bar 5 going from 50ºF to 74ºF.

Easy to remember: Hold up one hand, see 5 fingers ... Bar 5, 50 degrees, and 5 times 5 is 25, just five-fifths (1 hand) over 24 degrees.

So, these 4 bars (4 through 7) cover 96ºF of operating temperature, from 26ºF to 122ºF, or the very wide "normal" operating range. Typically, a "mild climate" shows bar 5, and warm summers sometimes shows bar 6.

With some recent logs made during QC sessions, I hope to identify the quickly-rising Battery Pack Temperature for the next firmware upgrade to the SOC-Meter.

 

[iluvmacs]

I've had my Leaf about a month here in Wisconsin. Until last week, our temps were unseasonably warm, around 30-45°F, and my battery temp was consistently at 4-5 bars. Last week, it turned bitterly cold, and I've seen two bars around 5-10°F, and even just one lonely bar at 0°F or below.

No idea if the battery warmer kicked in on the day I saw one bar, but it would have been awfully close to turning on if it didn't. The good news is that even with only 1 bar, the car drove just like normal. I was surprised to see that I had full power output available, though I only had one regen bubble available. My trip that day was pretty short (6 mi R/T), so I didn't get a good feel for range decrease, but I still averaged over 3 MPKWh!

 

[TonyWilliams]

I only had one regen bubble available. My trip that day was pretty short (6 mi R/T), so I didn't get a good feel for range decrease, but I still averaged over 3 MPKWh!

Good job! Is that with the heater on?

I'll repost some previous stuff for reference on this thread:

From Service Manual, April 2011, page EVB-140:

Battery temperature    

Rear RH & Front RH      1 and 2    
Rear center & Front LH  3 and 4   
 
°C (°F)   Resistance (kOhms)

-20  (-4)   Approx. 27.5
-10  (14)   Approx. 18.0
0    (32)   Approx. 12.0
10  (50)   Approx. 7.4
25  (77)   Approx. 4.0
40 (104)  Approx. 2.3
55 (131) Limit

 

[GaslessInSeattle]

From reading through the above, maybe the battery temp gauge is designed simply to help us avoid overheating the battery and not much else. I would very much like to know the actual temp to help determine the ideal target temp for ideal range. I haven't seen it below 4 bars and can generally get it to rise to 5 by prolonged prewarming, charging from 80 to 100%, which may explain why I'm still getting nearly the same miles out of the battery that I did in the summer under nearly identical driving habits and routes.

since the range during the coldest whether is going to define the maximum range someone in a given region can expect to do for a commute, it seems imperative that we find some way to track the actual battery temperature and determine if prewarming/charging or anything else really can reliably maintain improved range. Until we have solid numbers it's going to be hard to tell people with longer than average commute if the car is suitable for them.

 

[garygid]

I have logs of the three CAN buses while doing a QC.

The "rapid" rise in Pack Temperature should be
"easier" to spot for the SOC-Meter to display ... I hope!

 

[iluvmacs]

I only had one regen bubble available. My trip that day was pretty short (6 mi R/T), so I didn't get a good feel for range decrease, but I still averaged over 3 MPKWh!

Good job! Is that with the heater on?

No, I don't ever really run the cabin heater. The defrost is often on at the lowest setting for the windshield, which is nearly always sufficient. I can't remember defrost usage on that particular day.

 

[GREENEV]

Does anyone know why my battery temperature gauge has not moved one bit in 2 months or so? It used to fluctuate constantly.

 

[planet4ever]

Does anyone know why my battery temperature gauge has not moved one bit in 2 months or so? It used to fluctuate constantly.

Mine (on my 2011) sat at 5 bars all winter and 6 bars most of the summer. Those central bars have a very wide temperature range, roughly 25°F per bar. Perhaps your battery's typical winter temperature was close to a transition point, or was down at 4 bars or less where the range per bar is much narrower.

Ray

 

[TomT]

Ditto here.

Mine (on my 2011) sat at 5 bars all winter and 6 bars most of the summer.