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Discussion Starter · #1 ·
Hi all,
Are there any do's and don't for maximising the life of a Leaf battery?
I bought my SH 30KW leaf a month ago, it's got 36K miles on it, and so far so good on battery health. How do I keep it that way? Does it matter how I charge it... Or how low it gets or how full I charge to?

If I keep the car for several years when will battery degradation start to be an issue - either restricting the useful range or devaluing the car?

I'm hoping Nissan batteries behave differently to the shocking ones in Apple phones.

Thanks for sharing the wisdom.
 

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Leaf 30kWh, HS PHEV
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Hi all,
Are there any do's and don't for maximising the life of a Leaf battery?
I bought my SH 30KW leaf a month ago, it's got 36K miles on it, and so far so good on battery health. How do I keep it that way? Does it matter how I charge it... Or how low it gets or how full I charge to?

If I keep the car for several years when will battery degradation start to be an issue - either restricting the useful range or devaluing the car?

I'm hoping Nissan batteries behave differently to the shocking ones in Apple phones.

Thanks for sharing the wisdom.
Comparing phone batteries with car batteries isn't fair. Phone battery gets abused much more.

Good usage guide to Li-ion Batteries
DoD dictates total cycles.
Leaf30 charged to a max 4.1v and discharged to 3.3? I haven't tested the lower voltage significantly.

Try not to discharge it before 20%. Charge it based on your usage.

I tend to charge it full if my other half needs 50% capacity. If not needed, I don't charge it... Rare occasions as we use it the most.
 

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Lab tests show that keeping your battery as young as possible is the way to go. Age is a major problem, don't let it get old...

;) :sneaky:

Lab tests also suggest that using the high and low extremes of SOC, especially when the battery is hot, is the way to kill it the quickest.

Difficult to tell in real life because experience so far of such users as taxi fleets with mega miles and charging to 100% every day do not suggest that is so harmful as simply getting old. I keep mine mid SOC when I can but am not remotely concerned about high and low charges, but avoid leaving it at 100% for more than a day if I can help it. I think long dwells at 100% are the worst you can do for the car, given there is little else that is really *known* to be a big factor (other than sheer age).

HTH
 

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The answers to your questions are much like "how long is a piece of string". There doesn't seem to be one thing that makes a world of difference, but there is things you can do to "help".

My Leaf (24kw) battery health is better by 2% than when I bought it last August, so I must be doing better than the previous owner. I put it down to trying to be sensible with the charging. I drive short distances so for me, I charge once every two or three days instead of plugging it in and keeping it "topped up" all the time. I'll let it get down to 25 - 30% and sometimes lower before plugging in and charge to about 80 - 90%. I'm sure you have already read on here that leaving lithium batteries at 100% for long periods isn't the best practice. Although there are a few YouTube video's out there that say it doesn't do any harm, I air on the side of caution with such an expensive battery pack. About once a month, I'll charge to 100%, unplug it, let it sit for ten minutes then plug it in again. I do that a few times so it gets a proper "full charge". I'm not sure if that's the right thing to do, but to me it feels right. It worked well on my electric motorcycle project and I'm pretty sure it doesn't hurt. After doing it, I go for a drive so it's not sitting at 100% for long.

I've no idea when the battery health will start to affect the value of the car. Something I'm not worrying about until the time comes and hopefully there will be options to replace the pack by then...
 

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Discussion Starter · #6 ·
The answers to your questions are much like "how long is a piece of string". There doesn't seem to be one thing that makes a world of difference, but there is things you can do to "help".

My Leaf (24kw) battery health is better by 2% than when I bought it last August, so I must be doing better than the previous owner. I put it down to trying to be sensible with the charging. I drive short distances so for me, I charge once every two or three days instead of plugging it in and keeping it "topped up" all the time. I'll let it get down to 25 - 30% and sometimes lower before plugging in and charge to about 80 - 90%. I'm sure you have already read on here that leaving lithium batteries at 100% for long periods isn't the best practice. Although there are a few YouTube video's out there that say it doesn't do any harm, I air on the side of caution with such an expensive battery pack. About once a month, I'll charge to 100%, unplug it, let it sit for ten minutes then plug it in again. I do that a few times so it gets a proper "full charge". I'm not sure if that's the right thing to do, but to me it feels right. It worked well on my electric motorcycle project and I'm pretty sure it doesn't hurt. After doing it, I go for a drive so it's not sitting at 100% for long.

I've no idea when the battery health will start to affect the value of the car. Something I'm not worrying about until the time comes and hopefully there will be options to replace the pack by then...
Interesting.
So your kind of conditioning the battery with the rest and recharge approach. I was guessing the software would do that for me.
 

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Thanks,

So charging to 90-95% rather than 100% may help,
and avoiding going below 20% on a regular basis may help?

Not getting old is a bit of a challenge...
Yes, if you need to go that far (70% worth).

I use ~30% per day commuting so I charge daily from ~40%~70%. Simple. Oakridge labs data says I can get 10,000 charges of that cycling, so that'd mean 500,000 miles if I keep that up.

The reason for this is that the carbon electrode physically swells and stretches as it accumulates lithium ions. If you want it to last the longest, then stretch it as little as possible. Also, as the cell voltage reaches highs and lows you get oxidising and reducing effects on the electrolyte.

Have you heard of 'Goldilocks and the 3 bears?'? :)
 

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Thanks,

So charging to 90-95% rather than 100% may help,
and avoiding going below 20% on a regular basis may help?

Not getting old is a bit of a challenge...
3.93v is apparently the best for capacity vs total cycles.

Leaf30 as charges to 4.1 so ideally you've already doubled theoretical full cycles.

Not fully discharging it would mean you have cut down the DoD thereby increasing available cycles.

Here's my logging of charge, voltage and battery health in general
 

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My Leaf (24kw) battery health is better by 2% than when I bought it last August, so I must be doing better than the previous owner. I put it down to trying to be sensible with the charging.
Sorry to be the skeptic in the room but it has to be pointed out that there is no way your battery health is "better" now that when you bought it, no matter how you treat it.

There is no known mechanism by which a degraded Lithium Ion battery can be "rejuvenated". These are not Lead Acid cells or other cell types that do have actual rejuvenation mechanisms. What you are seeing are artefacts of the inherent error and uncertainties in the car's BMS estimating the state of health of the battery.

Changes in the measurements circumstances afforded the BMS such as driving and charging patterns can lead to a different measurement result for the exact same battery condition. The reported SoH may have gone up but the battery's true health can't have improved.

A change in reported SoH of 2%, even if it was in the downwards direction is well within the realms of measurement error and uncertainty anyway. Only trends over longer periods of time with more degradation than this would have any real meaning. One reason for this is that actual measurements are quite infrequent and in between those measurements the BMS applies a degradation prediction model to predict where it thinks the SoH probably is now based on factors such as elapsed time, mileage, cell temperatures etc. Probably is the key word here. It's a bit like your power company sending you an estimated bill because you haven't sent any meter readings for a few months.
 

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Sorry to be the skeptic in the room but it has to be pointed out that there is no way your battery health is "better" now that when you bought it, no matter how you treat it.

There is no known mechanism by which a degraded Lithium Ion battery can be "rejuvenated". These are not Lead Acid cells or other cell types that do have actual rejuvenation mechanisms. What you are seeing are artefacts of the inherent error and uncertainties in the car's BMS estimating the state of health of the battery.

Changes in the measurements circumstances afforded the BMS such as driving and charging patterns can lead to a different measurement result for the exact same battery condition. The reported SoH may have gone up but the battery's true health can't have improved.

A change in reported SoH of 2%, even if it was in the downwards direction is well within the realms of measurement error and uncertainty anyway. Only trends over longer periods of time with more degradation than this would have any real meaning. One reason for this is that actual measurements are quite infrequent and in between those measurements the BMS applies a degradation prediction model to predict where it thinks the SoH probably is now based on factors such as elapsed time, mileage, cell temperatures etc. Probably is the key word here. It's a bit like your power company sending you an estimated bill because you haven't sent any meter readings for a few months.
It's possible that with larger charge / discharge, the capacity measurement has improved resulting in overall increase in capacity being shown
 

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Interesting.
So your kind of conditioning the battery with the rest and recharge approach. I was guessing the software would do that for me.
Maybe it does, but I assumed that the BMS cuts off when the battery pack gets to a certain voltage. As the higher cells bleed off into the lower ones during balancing, that high end voltage would drop so plugging back in brings it back up. That's how it works in my head anyway. The fact that after resting it will take more charge sort of confirms that (again, only in my head).

Maybe in a few years I'll have 100% health! Then I'll wake up and eat my cornflakes. :ROFLMAO:

Maybe you are right Hermit Dave. I agree that it's impossible for the battery to be healthier than it was seven months ago. I only have the leafspy figures to go on. I test it once a month when the battery is resting around the 80% charge each time. Of course there are a lot of other variables out of anyone's control, but I do my best to be reasonably consistent when I'm plugging in the dongle.
 

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Is there a way of programming my Leaf to charge to less than 100%?
Is it a case of using the timer and doing some maths?
The Leaf 24 has a "long life mode" that limits charges at 80% (unless you use the timer to charge to 100%, or activate remote climate control while it's plugged in). So far as I know the Leaf 30 doesn't have that option though - but I may of course be wrong on that.

So likely a bit of mental maths and the use of the charge timer!
 

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Or do what I do and rip the plug from it's nose when I think it's cooked!
 

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Discussion Starter · #19 ·
Or do what I do and rip the plug from it's nose when I think it's cooked!
Hmmm, We tend to charge overnight... I don't fancy getting up and going outside at 5AM to unplug. Why on earth did Nissan only give us "start charging" in the App, but no "stop charging" option?
I think creative use of the timer is the order of the day...
 

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Hmmm, We tend to charge overnight... I don't fancy getting up and going outside at 5AM to unplug. Why on earth did Nissan only give us "start charging" in the App, but no "stop charging" option?
I think creative use of the timer is the order of the day...
I used timer everyday when i was charging using granny charger through smart socket.

Now i charge 100% or don't charge at all.. nothing in between.
 
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