Battery temp management for new leaf

[johnlocke]

OK I did a DCFC today from 37% to 100%, I started at 82 degrees battery temp with 74 degree ambient. ended at 100.2 degrees battery temp with ambient still at 74 degrees. For whatever good it does, the temp gauge went from 6 bars to 8 bars.

I have in the past pushed the battery to 11 bars (112 degrees according to Leaf Spy). It was really hot day and I had to DCFC to get home but I wouldn't recommend it.

As an interesting note, I was still charging at over 30 KW even with the battery at over 95% and was still drawing 13 KW even at the end.

[cwerdna]

OK I did a DCFC today from 37% to 100%, I started at 82 degrees battery temp with 74 degree ambient. ended at 100.2 degrees battery temp with ambient still at 74 degrees. For whatever good it does, the temp gauge went from 6 bars to 8 bars.

I have in the past pushed the battery to 11 bars (112 degrees according to Leaf Spy). It was really hot day and I had to DCFC to get home but I wouldn't recommend it.

As an interesting note, I was still charging at over 30 KW even with the battery at over 95% and was still drawing 13 KW even at the end.

You have a 30 kWh battery Leaf, right?

This is even more evidence beyond what I already had w/24 kWh Leafs that the "80%" DC FC "unwritten rule" as to when to yield and change to L2 is incorrect. When I had a Leaf w/CHAdeMO, I've been past 90% w/the rate still being higher than my car's max L2 rate of 6.6 kW.

[DaveinOlyWA]

OK I did a DCFC today from 37% to 100%, I started at 82 degrees battery temp with 74 degree ambient. ended at 100.2 degrees battery temp with ambient still at 74 degrees. For whatever good it does, the temp gauge went from 6 bars to 8 bars.

I have in the past pushed the battery to 11 bars (112 degrees according to Leaf Spy). It was really hot day and I had to DCFC to get home but I wouldn't recommend it.

As an interesting note, I was still charging at over 30 KW even with the battery at over 95% and was still drawing 13 KW even at the end.

is that a typo? Because that is significantly different than what I am seeing. Now I have 3 sensors where 2 are close but one is generally 5-10º cooler. Is this the lowest sensor you are referring to?

[johnlocke]

OK I did a DCFC today from 37% to 100%, I started at 82 degrees battery temp with 74 degree ambient. ended at 100.2 degrees battery temp with ambient still at 74 degrees. For whatever good it does, the temp gauge went from 6 bars to 8 bars.

I have in the past pushed the battery to 11 bars (112 degrees according to Leaf Spy). It was really hot day and I had to DCFC to get home but I wouldn't recommend it.

As an interesting note, I was still charging at over 30 KW even with the battery at over 95% and was still drawing 13 KW even at the end.

is that a typo? Because that is significantly different than what I am seeing. Now I have 3 sensors where 2 are close but one is generally 5-10º cooler. Is this the lowest sensor you are referring to?

Not a typo unfortunately. I was referring to the highest value shown in Leaf Spy but my sensors usually don't have more than a 5 degree spread. And yes I do own a 30 KWH 2016 currently at 73% SOH and 268 GID's full charge. To be fair, it was a 90+ degree day and the battery started at 8 or 9 bars (I don't remember which) but I had to get home so I charged it anyway.

[DaveinOlyWA]

OK I did a DCFC today from 37% to 100%, I started at 82 degrees battery temp with 74 degree ambient. ended at 100.2 degrees battery temp with ambient still at 74 degrees. For whatever good it does, the temp gauge went from 6 bars to 8 bars.

I have in the past pushed the battery to 11 bars (112 degrees according to Leaf Spy). It was really hot day and I had to DCFC to get home but I wouldn't recommend it.

As an interesting note, I was still charging at over 30 KW even with the battery at over 95% and was still drawing 13 KW even at the end.

is that a typo? Because that is significantly different than what I am seeing. Now I have 3 sensors where 2 are close but one is generally 5-10º cooler. Is this the lowest sensor you are referring to?

Not a typo unfortunately. I was referring to the highest value shown in Leaf Spy but my sensors usually don't have more than a 5 degree spread. And yes I do own a 30 KWH 2016 currently at 73% SOH and 268 GID's full charge. To be fair, it was a 90+ degree day and the battery started at 8 or 9 bars (I don't remember which) but I had to get home so I charged it anyway.

interesting. I generally don't hit "10" bars until after 124º F 11 bars around 128º

Sounds like the "temperature" bars take other things into account other than temperature.

I would venture to say that your "11 bar temperature turn on" has been creeping downwards with your range.

Granted this was a while ago but I just repeated this trip in Mid Sept with nothing significantly different including temperatures despite average temps in the upper 70's... check out the temps for my car.

http://daveinolywa.blogspot.com/2017/03 ... urney.html

[BuckMkII]

OT: Dave, are those the usual Ecopias? What is your cold inflation temp?

I just replaced original tires with Ecopia Plus a few weeks ago. I expected that losing the worn, thinner, and so presumably more supple tread would cost me efficiency, and indeed I seem to be off by a half mile per kWh. I have been staying at the sidewall max of 40 PSI cold. I'm probably going to push past that a bit since my driving is all a low speed and, for the next 7-8 months, low temps.

[DaveinOlyWA]

OT: Dave, are those the usual Ecopias? What is your cold inflation temp?

I just replaced original tires with Ecopia Plus a few weeks ago. I expected that losing the worn, thinner, and so presumably more supple tread would cost me efficiency, and indeed I seem to be off by a half mile per kWh. I have been staying at the sidewall max of 40 PSI cold. I'm probably going to push past that a bit since my driving is all a low speed and, for the next 7-8 months, low temps.

Those are OEMs and my cold pressure target is always the Max sidewall pressure. Can't remember the last time I saw a passenger tire with 40 PSI listed. (if ever?)

[Nubo]

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.

Psychology and obfuscation. The same reason the last SOC bar is so much wider than the others or why the first capacity bar is so much wider than the others. Carmakers are like Col. Nathan Jessup -- they don't think you can handle the truth.

And sometimes they're right. I remember my original Miata had a functional oil pressure gauge, which was useful for judging when the car was warmed up. But too many owners weren't familiar with how viscosity changes with temperature and would freak out either over the high initial pressure, or the big drop when warmed up. Mazda got tired of the inquiries and complaints and in future vehicles chose a unit that was an idiot-light masquerading as a pressure gauge.

[johnlocke]

Right in the manual it states that the temp bars represent a range of values and that the range for a given bar can overlap the ranges for other bars. What that depends upon is anybody's guess! The highest temp I ever saw was 117 degrees and still 11 bars. If I recall correctly, the system will throttle back output if the temp exceeds 122 degrees.

[DaveinOlyWA]

Right in the manual it states that the temp bars represent a range of values and that the range for a given bar can overlap the ranges for other bars. What that depends upon is anybody's guess! The highest temp I ever saw was 117 degrees and still 11 bars. If I recall correctly, the system will throttle back output if the temp exceeds 122 degrees.

Been over 122º dozens of times and only saw one "possible" time that the speed of the fast charge might have been throttled. Was expecting roughly 45-46 KW and it was only running at 30 KW. I think I only had 9-10 bars at the time