Cell Balancing - Does Charging to 80% Prevent it - Any tips?

[reeler]

I have probably charged to 100% no more than a handful of times. As I understand things, the Leaf does cell balancing upon reaching 100%. I am not sure how long it takes to perform the cell balancing.

Will charging only to 80% cause decreased range and increased wear on the cells in the battery pack? Should we purposefully charge to 100% at some interval--say once a month?

Are there any rules of thumb that would keep our battery packs in tip-top shape?

 

[djchrispaul]

I was wondering the same thing, I charge to 80% most of the time and get 10 of 12 bars but yesterday and today I only got 9 of 12!
I just charged to 100% to see if I was going to only get 11of 12 but happily I got 12 of 12, so popped out and drove slowly and lost a bar after 4 miles. Not sure what all this means but maybe it's good to charge to 100% as you say monthly, looking forward to some expert replies!

 

[planet4ever]

This is not an expert reply, but based on the more expert comments I have seen, unbalanced cells apparently don't damage the battery in any permanent way. My impression is that they merely reduce its effective capacity. If that is true, then there is nothing to worry about here. If you get all the range you need with an 80% charge, then stick with it. Charge to 100% any time you need more range, and guess what, cell balancing will take care of itself.

Well, with the exception that if you need to charge to 100%, then maybe once a month or so you should arrange things so that the car sits still plugged in for four or more hours after the charge completes.

Ray

 

[TEG]

I almost always charge to 80% most of the time.
Rarely, I need to take a longer trip, so I may do 100% say once every two months.
I haven't noticed any sort of reduction in range. It 'feels' like my pack has been staying balanced even though I don't generally use 100% charging.

 

[ebill3]

This is not an expert reply, but based on the more expert comments I have seen, unbalanced cells apparently don't damage the battery in any permanent way. My impression is that they merely reduce its effective capacity. If that is true, then there is nothing to worry about here. If you get all the range you need with an 80% charge, then stick with it. Charge to 100% any time you need more range, and guess what, cell balancing will take care of itself.

Well, with the exception that if you need to charge to 100%, then maybe once a month or so you should arrange things so that the car sits still plugged in for four or more hours after the charge completes.

More non-expert advice:

Do the 100% charge without timer - not an override of the 80% charge. I don not think balancing will occur with an 80% charge overridden. Expert comment?

Bill

 

[DaveinOlyWA]

i think cells balance all the time but more effectively at 100%.

if you have a pack where the #1 concern is not overcharging, then you approach full with caution and better to be safer than sorry right?

with 80% balancing, its not an issue so not a big deal if off by a few %. at 100% usable capacity, you are simply way to close to take chances which is why you see "corrective" charging.

the car would rather stop short and correct it than overshoot the full mark.

i have to say my recommendation; if you can live with the range limitations; keep your SOC between 40-80% AT ALL TIMES.

if you cant, no worries. short periods of time at 100% is ok. i rarely charge to 100% but have done it much more frequently lately and my GID count has hit 280 3 times in the past week. so i am still pretty much where i started

 

[EVDRIVER]

Ask this simple question. Would Nissan advocate 80% charging without some provision of balancing if needed? They just overlooked that small detail in the design of the BMS because they were too busy one day? I don't remember the manual saying "We leave it up to owners to figure out how to balance the pack when needed" Luckily they thought of keeping the car from driving away while plugged in Many simple questions on this forum can be answered with 10 seconds of common sense logic. Since Nissan expects many consumers to be challenged to just plug the car in they certainly don't expect them to figure out how to best manage the pack balancing.

 

[garygid]

If one needs to TURN OFF the Timer to Equalize the cells,
that would be new news. I doubt that it's necessary.

I never charge without the timer, set to "anytime" and 80%,
or by using the Timer-Override to charge to 100%.

 

[GaslessInSeattle]

I think you are right in this instance, but given the omissions for Phoenix and Southern CA, I'm not so confident in general that they thought it all through as well as I used to used be.

Ask this simple question. Would Nissan advocate 80% charging without some provision of balancing if needed? They just overlooked that small detail in the design of the BMS because they were too busy one day? I don't remember the manual saying "We leave it up to owners to figure out how to balance the pack when needed" Luckily they thought of keeping the car from driving away while plugged in Many simple questions on this forum can be answered with 10 seconds of common sense logic. Since Nissan expects many consumers to be challenged to just plug the car in they certainly don't expect them to figure out how to best manage the pack balancing.

 

[EdmondLeaf]

I think you are right in this instance, but given the omissions for Phoenix and Southern CA,

and TX (I think)

 

[reeler]

Has anyone observed how long it takes to do the cell balancing on the Leaf? Someone with a meter hooked to their Leaf might be able to determine this.

When I charge to 100% (usually by pressing the override button), I only leave it at 100% for less than a couple hours.

Thanks for all the comments, but I think I would like to charge to 100% about once a month leaving enough time to complete the cell balancing routine.

 

[ebill3]

Has anyone observed how long it takes to do the cell balancing on the Leaf? Someone with a meter hooked to their Leaf might be able to determine this.

When I charge to 100% (usually by pressing the override button), I only leave it at 100% for less than a couple hours.

Thanks for all the comments, but I think I would like to charge to 100% about once a month leaving enough time to complete the cell balancing routine.

Six hours.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=8765&p=196214&hilit=6+hours#p196214" onclick="window.open(this.href);return false;

Bill

 

[TonyWilliams]

Has anyone observed how long it takes to do the cell balancing on the Leaf? Someone with a meter hooked to their Leaf might be able to determine this.

When I charge to 100% (usually by pressing the override button), I only leave it at 100% for less than a couple hours.

Thanks for all the comments, but I think I would like to charge to 100% about once a month leaving enough time to complete the cell balancing routine.

Six hours.

http://www.mynissanleaf.com/viewtopic.php?f=30&t=8765&p=196214&hilit=6+hours#p196214" onclick="window.open(this.href);return false;

Bill

The longest period of time I have observed (and that was with some serious jacked up out of balance) was a bit over 4 hours. Immediately after, the car returned to "full performance".

 

[TonyWilliams]

Ask this simple question. Would Nissan advocate 80% charging without some provision of balancing if needed? They just overlooked that small detail in the design of the BMS because they were too busy one day? I don't remember the manual saying...

Yes, you mention this frequently. My "common sense" says that:

1. That manual is factually challenged in many areas. Love the pics showing exhaust systems, et al. How about 403v pack (4.2v per cell)? Lots and lots of others.

2. Nissan isn't spilling their guts with everything they know about the car in that manual.

3. I'm confident that the BMS works quite well.

4. 80% charging to 4.05v per cell is critical to the longest life of the cell (compared to higher voltages)

5. Longest life at 80% has nothing to do with balancing. Nissan will never have a warranty claim for out of balance cells that the automation can easily fix. They will for cars left at 100% in Phoenix in May for a month.

6. Nissan originally said one quick charge per day. Now, the revised manual says more. The reality is neither is a good idea if the battery is hot.

 

[LEAFfan]

Hot is a relative term. QCing when the temp gauge is up to 9 bars/12 is okay. If it goes to 10 bars (may let you drive up to 25mph), then I would wait until it drops to at least 9. It doesn't have to be in the red to be hot.

 

[jwatte]

In reality, 90 degrees Farenheit (30 degrees Centigrade) is "hot" for Lithium Ion. I'm in Northern California, and have to park outside at work, and we get that temperature in the summer.
I trickle charge at work, and never to more than 80%, though, so at least it's not adding more heat.

 

[bej]

I have a 2013 leaf. Just got it from someone who claims they never charged above 80%. I charged a few times to 80% and noticed that it does full charge(about 1400w) until the end when the charging indicator lights all turn off(shown in pics). Today I had to go a longish distance and charged to 100% starting at about 2am. This morning I noticed that it still indicated charging but slowly tapered off and went in 5 minute cycles of off and on 3 times. After this it stopped charging so I unplugged and plugged in the charger. This yielded about 4 more cycles and 1 more mile estimated range till the charging lights all lit up and seemed to not take any more charging though I couldn't test this fully as I had to go somewhere. This is making me think that the bms is actually balancing the cells when charging to 100% as opposed to only 80% though this usually takes a long time to balance the cells if they haven't been balanced for a while so I am not totally positive. Maybe my cells were in balance already or the balancer in the bms is super fast... dunno. Feel free to check out the pics to see it in action:

https://photos.app.goo.gl/iVCEvKudiyimZ6Wc9

 

[LeftieBiker]

Welcome. The charge to 100% (indicated) is only one of the times when the cells balance. It is an ongoing process whenever the car is On, although the BMS can't shunt large currents, so when you are actually driving the overall effect is small.

 

[Learjet]

11 year old thread brought back to life

 

[LeftieBiker]

Cthulhu smiles when someone resurrects a long-dead argument.