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Repetitive charging: What is defined as "high battery state of charge"

Posted: Sun Jan 15, 2017 3:55 pm
by ATXLeaf
Need some advice with the statement in the 2017 Nissan Leaf (SV) manual on page EV-24 :
"Avoid repetitive charging of the Li-ion battery with high battery state of charge."

What is typically defined as "high battery state of charge" ? 95%, 90%, 80%, 70%, ... ?

More specifically, sometimes we only use 10% or less for a trip. Would it be better to wait with charging until the level dropped to what ?? % ????
----> Even if that means the car will not be charged to 100% for a week, sometimes 2 weeks?

Thank you for any pointers, hints, tips and best practice advice.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sun Jan 15, 2017 4:18 pm
by LeftieBiker
You won't get any numbers from Nissan, but it's safe to assume that charging when the car already has more than 80% charge should be avoided unless it's necessary. Don't obsess over it, though. It's better to charge only when the pack falls below 60-70% or so, as long as that doesn't put you at risk of running out of range. An occasional charge to 100% will help keep the pack's cells balanced, though - just don't let the car sit at 100% for more than a few hours if you can avoid it.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sun Jan 15, 2017 4:22 pm
by DaveinOlyWA
don't worry about it. the only thing you should be worrying about is making sure you have the charge you need.

Now, you should also consider working on predicting your needs. for some that is easy; their life is very predictable. for others, it could be a struggle.

But generally, don't leave your car at very low SOC (use the warnings for a guide) or let it sit fully charged longer than is necessary. its ok every once in a while and if its cold, that is even better.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sun Jan 15, 2017 7:00 pm
by ATXLeaf
That was my thinking, to let it go to below 60% before charging it to 100 again.

As I said we usually only need 10 - 15% per trip/day and don't even drive it every day.

So with the answers from my other thread I gather that it is OK to let it sit at lower % (but not below 40%) and charge it when a bigger drive is planned.

No problem with the ChargePoint we have and agreed to be on the save side and always have plenty charged :D

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sun Jan 15, 2017 7:08 pm
by DaveinOlyWA
ATXLeaf wrote:That was my thinking, to let it go to below 60% before charging it to 100 again.

As I said we usually only need 10 - 15% per trip/day and don't even drive it every day.

So with the answers from my other thread I gather that it is OK to let it sit at lower % (but not below 40%) and charge it when a bigger drive is planned.

No problem with the ChargePoint we have and agreed to be on the save side and always have plenty charged :D
for your level of need, I would never charge to 100%.... sounds like you would be better off keeping it in the 40 to 75% range.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sun Jan 15, 2017 7:51 pm
by LeftieBiker
for your level of need, I would never charge to 100%.... sounds like you would be better off keeping it in the 40 to 75% range.
The Leaf's battery pack is "top balanced" which means that the cells are equalized in voltage by the BMS only when the pack is fully charged. This doesn't have to be done often, but it should be done regularly.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Thu Jan 19, 2017 3:42 pm
by arnis
High battery charge state is over 80%. Do not cycle battery between 80-100% on regular basis.
If you are not able to set 80% limit (there are two options: "battery saving mode" and timers with 80% option).
Then you might let car charge for limited time, either with timer or manually.
Let it discharge to at least 60% before charging to 80%.
Need more then discharge to 40% and then charge to 80%.
Need more then let it discharge to 40% and charge to 90%.

Charge to 100% once a month.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sat Jan 21, 2017 8:28 am
by DaveinOlyWA
LeftieBiker wrote:
for your level of need, I would never charge to 100%.... sounds like you would be better off keeping it in the 40 to 75% range.
The Leaf's battery pack is "top balanced" which means that the cells are equalized in voltage by the BMS only when the pack is fully charged. This doesn't have to be done often, but it should be done regularly.
only benefit to top end balancing is more range. if you never need that range, then its simply not that necessary. It would be worse to charge it to 100% then take two days to get it back down to 75% or something.

Saying that; its always better to have more than you think you need. If planning on driving more than 30-40 miles that day, I would charge to full. Its all about understanding how your needs mesh with best practices while knowing best practices may only have a very small benefit that can easily be overcome by one incident of not having the charge you need.

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sat Jan 21, 2017 10:28 am
by Oils4AsphaultOnly
arnis wrote:High battery charge state is over 80%. Do not cycle battery between 80-100% on regular basis.
If you are not able to set 80% limit (there are two options: "battery saving mode" and timers with 80% option).
Then you might let car charge for limited time, either with timer or manually.
Let it discharge to at least 60% before charging to 80%.
Need more then discharge to 40% and then charge to 80%.
Need more then let it discharge to 40% and charge to 90%.

Charge to 100% once a month.
What is this "battery saving mode"? If you're referring to "B" mode, how do I trigger it when parked for charging? I got an S30 without realizing that they took away the 80% charge limit. :(

Re: Repetitive charging: What is defined as "high battery state of charge"

Posted: Sat Jan 21, 2017 12:46 pm
by LeftieBiker
"Battery saving mode" is the 80% charge limit menu option that only 2013 Leafs have.