Wait to cool first or charge spent battery first?

So I'm in Phoenix where normally I come home with 7 temperature bars. Obviously Nissan says to wait for battery to cool down first before charging. It can take a LONG time for the battery to cool down to 6 bars inside a hot garage in Phoenix.

Now here's my other dilemma: Sometimes I come home with just 1 or 2 bars left. Common sense also says to not allow the battery to sit at a deep discharge state for too long.

So which is more important? Wait for it to cool first (using an end timer by morning) at the expense of being in a discharge state for a long time (several hours)?

Or charge the hot battery up to maybe 3 or 4 bars first, then stop (before I go to bed), then charge to 80% with an end timer only to allow the battery to cool down?

If 7TBs I would wait

Temperature has a demonstrated adverse effect. Having 30% capacity left in the battery meets long term storage parameters.

Cool the battery.

Does anyone else see why this might be a design that will never be adopted by the masses. So Joe Consumer buys one of these, he really should not charge to 100%. He should not QC too often or charge too soon or let full charge stay on batteries too long. I could go on but this is starting to get ridiculous. Us first adopters know a lot of these things, but expecting the masses to do or don't do all of these things are going to kill this whole movement. Maybe all of this was not thought out very well.

TonyWilliams said:

Temperature has a demonstrated adverse effect. Having 30% capacity left in the battery meets long term storage parameters.

Cool the battery.

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+1

ebill3 said:

TonyWilliams said:

Temperature has a demonstrated adverse effect. Having 30% capacity left in the battery meets long term storage parameters.

Cool the battery.

Click to expand...

+1

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Yep, the only time I might consider charging immediately instead of waiting would be if the car was driven below VLBW. And then I would suggest only charging about an hour before delaying the rest of the charge as much as possible.

Volusiano said:

So I'm in Phoenix where normally I come home with 7 temperature bars. Obviously Nissan says to wait for battery to cool down first before charging. It can take a LONG time for the battery to cool down to 6 bars inside a hot garage in Phoenix.

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Do you close your garage door? I've been leaving mine open, or at least part way open until I'm ready to go to bed. That helps it cool off in there a lot faster. Because, yeah, it takes a while for the heat to dissipate in there. Even though the outside temperature may have dropped into the 80's, it can still be 100 degrees in the garage with the door left shut.

drees said:

Yep, the only time I might consider charging immediately instead of waiting would be if the car was driven below VLBW. And then I would suggest only charging about an hour before delaying the rest of the charge as much as possible.

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I try to charge immediately to 2-3 bars, whenever significantly below the LBW.

But I can avoid having 7 bars and a LBW (much less VLBW) at the same time.

Is there any reason, in theory, why low SOC in a very hot battery, is more or less damaging than low SOC, in a cooler one?

downeykp
Does anyone else see why this might be a design that will never be adopted by the masses. So Joe Consumer buys one of these, he really should not charge to 100%. He should not QC too often or charge too soon or let full charge stay on batteries too long. I could go on but this is starting to get ridiculous. Us first adopters know a lot of these things, but expecting the masses to do or don't do all of these things are going to kill this whole movement. Maybe all of this was not thought out very well.

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I think the real problem is is LEAF buyers whose purchase decision was "not thought out very well".

If your usual daily driving is not achievable on an 80% charge without going much below the LBW, a LEAF may not be right for you in the first place. Not because the LEAF cannot be used for longer daily travel, but because the thoughtfulness required for that level of operation, is beyond the ability of many drivers, as the use patterns of many of the bar loss LEAFs (those who have reported) illustrates.

Yes, with careful management, you probably can put 2,000 miles a month on a LEAF and still limit the time at very high and low SOC and very high temperatures (probably, even in Phoenix) which will lead to significantly shorter battery life.

I just think that the evidence is building, that not many are capable of doing this.

downeykp said:

Does anyone else see why this might be a design that will never be adopted by the masses. So Joe Consumer buys one of these, he really should not charge to 100%. He should not QC too often or charge too soon or let full charge stay on batteries too long. I could go on but this is starting to get ridiculous. Us first adopters know a lot of these things, but expecting the masses to do or don't do all of these things are going to kill this whole movement. Maybe all of this was not thought out very well.

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I asked OP question adding optimal battery temp, CS as well as people at NNA HQ. CS was not very helpful stating that as long as TB are in white area, battery will be fine. I am still waiting for HQ to answer, but not very optimistic because last email I sent to them was a week or so ago. Cooling battery takes long time and in my case I not only keep my garage door and window across completely open, but if temp outside at midnight still in 90 area I run ac till next morning. I also run box fun under battery area which helping some. So far with this routine I was able to keep battery in middle 80 area which now require running AC in garage every other day. This is my storage routine and car is not used from middle of June. It is not that easy to keep battery in reasonable temp without some kind of TMS, if temp gradient is not that much battery will cool maybe 1 or 2F within few hours. Sure, charging will drive battery temp up right on so even limited drop will help. I am not sure why Nissan is not helping us here but to me keeping battery in reasonable temp is an effort that takes so much time and resources as well I never expected I will be doing.

in my 5 Turtle events, i did not charge right away in any of those times and temperature was not an issue (3 turtles in winter with 4 TBs!) in all 3 cases. i finished the day around 5-6 PM, plugged in at 10-11 PM.

i have also been doing temperature checks as well and found that closing the garage door yesterday for 3 hours the temp rose to 35.5C. if opened, temp leveled out to 25.2 C within 30 minutes. this was during time that Sun was out (sundown is like (9:45 or so) and sets on the garage door. shade from trees does block a good portion of the direct sunlight as the Sun takes an angled path across the front so Sun only penetrates about 3-4 ft inside the garage. i did the same test with closing door for 2 hours after 6 PM. temps rose to 32.5 C but cooled to 23 C again within 20-30 minutes.

Install a window swamp cooler in your garage.. they use very little power, basically just an electric fan bringing in external air. The average monthly wet bulb temperature in Phoenix ranges from 43° F (Dec) to 69° F (Aug) yearly, that is a very comfortable temperature range for lithium-ion batteries.

http://www.wrcc.dri.edu/htmlfiles/westcomp.wb.html" onclick="window.open(this.href);return false;

current conditions:
http://tiggrweather.net/" onclick="window.open(this.href);return false;

Volusiano said:

So I'm in Phoenix where normally I come home with 7 temperature bars. Obviously Nissan says to wait for battery to cool down first before charging.

Click to expand...

TonyWilliams said:

Temperature has a demonstrated adverse effect. Having 30% capacity left in the battery meets long term storage parameters.
Cool the battery.

Click to expand...

DaveinOlyWA said:

If 7TBs I would wait

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I'm confused by all this. Is 7 bars on the temp gauge considered high? That is well within the "white" area and still several bars below "red," which I thought was the high temp indicator. I have never seen any indication from Nissan that it is detrimental to charge the car on L2 when the temp gauge is at 7 bars. Maybe L3 could raise the temp during a charge more rapidly, but I have never seen the gauge go up by more than 1 bar during an L2 charge. Is this advice just predicated on "an abundance of caution" or has there been some actual engineering advice offered by Nissan that I have missed? The Battery Information Sheet that contains the recommendations for minimizing capacity loss certainly does not include advice to "never charge the battery if the temp gauge is at 7 bars or higher." Where is this fear coming from--has new info surfaced from the "Phoenix phenomenon" perhaps?

Granted, I am in a temperate climate and have never even seen 7 bars on my gauge (5 or 6 is the norm), but I would not have been shocked or worried if it reached that level, since it is well within the "normal" operating range, and would not have thought twice about plugging it in before it cooled down if I needed the charge, since it would still be in the "safe" area according to the documentation. Am I deluded or uninformed somehow?

TT

ttweed said:

I'm confused by this. Is 7 bars on the temp gauge considered high? That is well within the "white" area and still several bars below "red," which I thought was the high temp indicator.

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Yes, I consider it to be high. Remember that the Phoenix folks have their cars at 7 temperature bars for significant periods of time, and they are seeing a lot of degradation. We don't know how high into the 7 bar temperature band they are getting, since the bars are way too coarse to provide really useful information.

I have never seen any indication from Nissan that it is detrimental to charge the car on L2 when the temp gauge is at 7 bars.

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Yes, but Nissan does say not to charge right away after driving to let the battery pack cool down. Their advice is far too generic to be of much use, because if I have 5 temperature bars it really wouldn't matter if I charge right away--the battery is already at a nearly ideal temperature.

ttweed said:

I'm confused by all this. Is 7 bars on the temp gauge considered high? That is well within the "white" area and still several bars below "red," which I thought was the high temp indicator. I have never seen any indication from Nissan that it is detrimental to charge the car on L2 when the temp gauge is at 7 bars. ...

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It's all conjecture. We know that "normal" conditions in Phoenix are sufficient to cause degradation, so people are grasping for ways to improve the situation. But it's all just guesswork. We've had people who use all sorts of different charging regimens report capacity loss, so it's not clear that it's made much difference.

For the people who voted to let the battery sit in VLBW for a long time so it's had a chance to cool down first before charging, do you have any empirical evidence that shows your choice is the lesser of the 2 evils?

Sure, we know that 7TB causes degradation. But that's the damage due to 7TB already done no matter what. What we're really talking about here is new damage due to the difference between charging at 7TB vs 6TB.

How do we really know that this "new" damage is worse than the damage of letting the battery sit at VLBW for 6 hours?

Also, remember that we have 3 options:

1. Wait for the cool down then use end timer charging.
2. Charge right away all the way to get out of VLBW asap.
3. Charge right away to maybe 3 bars, then stop and cool down with end timer charging.

Most people seem to pick option 1 right away. Only 1 person mentioned option 3.

I was surprised to see that not too many people would go with option 3. Why wouldn't option 3 be the best of both worlds?

3. Charge right away to maybe 3 bars, then stop and cool down with end timer charging.

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that what I think is best and may increase your battery temp by 3 -4F which is not that much. Partial/shallow cycling is consider to be good for the battery

adric22 said:

Volusiano said:

So I'm in Phoenix where normally I come home with 7 temperature bars. Obviously Nissan says to wait for battery to cool down first before charging. It can take a LONG time for the battery to cool down to 6 bars inside a hot garage in Phoenix.

Click to expand...

Do you close your garage door? I've been leaving mine open, or at least part way open until I'm ready to go to bed. That helps it cool off in there a lot faster. Because, yeah, it takes a while for the heat to dissipate in there. Even though the outside temperature may have dropped into the 80's, it can still be 100 degrees in the garage with the door left shut.

Click to expand...

I leave it up just a tiny bit (an inch or so) to allow some air to get in for convection flow. But I don't leave it wide open for security purposes because I have lots of stuff in my garage.

edatoakrun said:

I think the real problem is is LEAF buyers whose purchase decision was "not thought out very well".

If your usual daily driving is not achievable on an 80% charge without going much below the LBW, a LEAF may not be right for you in the first place. Not because the LEAF cannot be used for longer daily travel, but because the thoughtfulness required for that level of operation, is beyond the ability of many drivers, as the use patterns of many of the bar loss LEAFs (those who have reported) illustrates.

Yes, with careful management, you probably can put 2,000 miles a month on a LEAF and still limit the time at very high and low SOC and very high temperatures (probably, even in Phoenix) which will lead to significantly shorter battery life.

I just think that the evidence is building, that not many are capable of doing this.

Click to expand...

I made the mistake of buying what I thought was a car, but apparently I bought a rolling orchid. I will start sitting in the garage and talking to it at night, so perhaps it won't lose any more bars.

I completely agree with downeykp. If the Leaf requires this level of care and "thoughtfulness", it will never sell to the general public. This isn't the seventies, when all cars required thoughtfulness and a little spay of carb fluid to get them started.

So the general consensus is to cool the battery then charge.

Scenario:
2 bars left/low battery warning when pulling into garage at 8pm with 7 temp bars+

Requirements:
50+ miles of charge/40-60% SOC by 7am

Resolution:
Set internal timer on vehicle to allow charge from 2am-7am or set delay on evse to delay 6 hours before charging


Are we pretty much agreed that's best solution?

My opinion of 7TBs is based on 2things. Phoenix user observations and "general" Li info that degradation ratds increase over 30C..

It is just an opinion