Limiting charge to LESS than 80%

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rasgaroo

Member
Joined
Jun 9, 2020
Messages
13
Here's my dilemma:

I usually travel less than 5 miles a day. If I charge my 2014 leaf to 80%, it will have to hold that charge for several weeks, or months.

I have been told that keeping a leaf charged higher than 50% for a long period is bad for the battery.

...

I think it can do better if I can limit the charging to like 45%. But I don't see a way to configure it below 80%. I can keep monitoring from time to time and cut the power when it reaches 45% - 50%.

But I have also been told that externally cutting the power or pulling the plug out before the car cuts if off is also bad for the battery.

Is there any truth to the last claim?

What do you suggest the best thing I can do in this situation?
 
rasgaroo said:
But I have also been told that externally cutting the power or pulling the plug out before the car cuts if off is also bad for the battery.

Is there any truth to the last claim?
No, but if you were to cut power, you should do it right (e.g. pushing the button on the J1772 handle to terminate charging or via timers). Do NOT pull the plug on the wall side of any EVSE while still actively charging. You will likely have arcing and that can lead to problems on that end later.

Also, some L2 EVSEs like Juicebox from what I hear let you specify a target charge level and can stop early (which is safe) when it guesses the charge level has been reached. You need to input your current/starting % SoC since the J1772 protocol doesn't have any means for the car to tell the EVSE the car's SOC (unlike for DC charging).
 
rasgaroo said:
I usually travel less than 5 miles a day. If I charge my 2014 leaf to 80%, it will have to hold that charge for several weeks, or months.
I'm not following your arithmetic
80% charge is somewhere in the range of 50 - 60 miles, so you remove 10% of your charge daily

I think you are fine, but figure you use ~ 1 kWh a day. Do you know the kW charge rate of your EVSE ? Say it is 6 kW. Then if you want to charge once a week you will charge for one hour.
 
cwerdna said:
No, but if you were to cut power, you should do it right (e.g. pushing the button on the J1772 handle to terminate charging or via timers). Do NOT pull the plug on the wall side of any EVSE while still actively charging. You will likely have arcing and that can lead to problems on that end later.
I thought that button only unlatches the handle. Are you saying that pushing that button electrically terminates charging?

When I want to cut power, I turn off the circuit breaker which is dedicated to charging the leaf. Is that safe?

cwerdna said:
Also, some L2 EVSEs like Juicebox from what I hear let you specify a target charge level...
I don't have an L2 charger, I think. I mean all I have is the one that came with the car:
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SageBrush said:
rasgaroo said:
I usually travel less than 5 miles a day. If I charge my 2014 leaf to 80%, it will have to hold that charge for several weeks, or months.
I'm not following your arithmetic
80% charge is somewhere in the range of 50 - 60 miles, so you remove 10% of your charge daily
Umm.... but I travel only two or three days a week! :D

SageBrush said:
I think you are fine, but figure you use ~ 1 kWh a day. Do you know the kW charge rate of your EVSE ? Say it is 6 kW. Then if you want to charge once a week you will charge for one hour.
That's what I was trying to do (without actually doing the math though). It's just I was told that suddenly cutting power without 'informing' the car first can be bad for the battery.
 
rasgaroo said:
I thought that button only unlatches the handle. Are you saying that pushing that button electrically terminates charging?
Yes. See https://openev.freshdesk.com/support/solutions/articles/6000052074-basics-of-sae-j1772 under proximity. Also see https://en.wikipedia.org/wiki/SAE_J1772#Safety. https://www.sae.org/binaries/content/assets/cm/content/standards/chargingprimer.pdf and http://www.fveaa.org/fb/J1772_386.pdf might also be insightful.

Next time when it's charging, hold down the button and wait for the thunk from the car. Observe that the car stops charging while you hold down the button.

Also, if you want to trigger an error, if you plug in while holding down the trigger, you will probably get all 3 blue lights on Leaf flashing in unison with beep-beep-beep-pause which repeats until you let go of it the trigger.
rasgaroo said:
When I want to cut power, I turn off the circuit breaker which is dedicated to charging the leaf. Is that safe?
I wouldn't advise always doing that. You'll wear out the breaker and there might be arcing inside it.

I was suggesting that you could get an L2 EVSE like Juicebox that lets you set a target SoC %.
rasgaroo said:
It's just I was told that suddenly cutting power without 'informing' the car first can be bad for the battery.
Who said that? Cutting power the wrong way can be bad for whatever arcs outside the car. It's not bad for the battery.

Ways to properly stop include: pressing the J1772 handle trigger, having the EVSE properly stop (e.g. via a stop button (some have it like https://www.plugincars.com/curious-what-750-gets-you-pics-guts-nissan-leafs-charge-station-106524.html), software to stop it, swiping an RFID card, etc.), or the car stopping like via charging timer.

(It can also be bad if the J1772 handle latch/tang is broken and you can pull the J1772 handle out of the car WITHOUT pressing the trigger while the car's charging. You might get arcing --> bad for inlet and handle.)

What trim level of Leaf do you have? If it's an SV or SL (has nav system), the charging timers are pretty easy to set. You can have it start late and/or end early. If it's an S trim, the timers are a pain to set.
 
cwerdna said:
Yes. See https://openev.freshdesk.com/support/solutions/articles/6000052074-basics-of-sae-j1772 under proximity. Also see https://en.wikipedia.org/wiki/SAE_J1772#Safety. https://www.sae.org/binaries/content/assets/cm/content/standards/chargingprimer.pdf and http://www.fveaa.org/fb/J1772_386.pdf might also be insightful.

Next time when it's charging, hold down the button and wait for the thunk from the car. Observe that the car stops charging while you hold down the button.

Also, if you want to trigger an error, if you plug in while holding down the trigger, you will probably get all 3 blue lights on Leaf flashing in unison with beep-beep-beep-pause which repeats until you let go of it the trigger.
Wow! I never knew it could do any of that. Thanks a lot!


cwerdna said:
rasgaroo said:
It's just I was told that suddenly cutting power without 'informing' the car first can be bad for the battery.
Who said that?
A guy at a local not-so-authorized nissan service center :) . His reasoning was like that there is a bunch of things the car needs to do with the battery circuit when it is about to stop charging, and if you stop charging without 'informing' the car first, the car wouldn't have enough time to do all those things, which can eventually be bad for the battery. It's fairly possible that he made it up on the spot! :)


cwerdna said:
What trim level of Leaf do you have? If it's an SV or SL (has nav system), the charging timers are pretty easy to set. You can have it start late and/or end early. If it's an S trim, the timers are a pain to set.
It's an X trim. Setting up a start/stop timer sounds like an excellent idea! I remember I saw that feature (thanks to the google translator) on the nav system, but I never realized that I could use it for this purpose.

Thanks a lot again!
 
rasgaroo said:
SageBrush said:
rasgaroo said:
I usually travel less than 5 miles a day. If I charge my 2014 leaf to 80%, it will have to hold that charge for several weeks, or months.
I'm not following your arithmetic
80% charge is somewhere in the range of 50 - 60 miles, so you remove 10% of your charge daily
Umm.... but I travel only two or three days a week! :D

SageBrush said:
I think you are fine, but figure you use ~ 1 kWh a day. Do you know the kW charge rate of your EVSE ? Say it is 6 kW. Then if you want to charge once a week you will charge for one hour.
That's what I was trying to do (without actually doing the math though). It's just I was told that suddenly cutting power without 'informing' the car first can be bad for the battery.
You have your answer from cwerdna how to stop a charge properly.

If you know when your next drive is, then charge an hour or two earlier to 80%, drive down to 70% and you are good.
 
rasgaroo said:
It's an X trim. Setting up a start/stop timer sounds like an excellent idea! I remember I saw that feature (thanks to the google translator) on the nav system, but I never realized that I could use it for this purpose.
We don't have an X trim in the US. We have S, SV and SL. From https://samholford.github.io/leafguide/, I guess X is like SV.

https://www.youtube.com/watch?v=WeR0SXzQdto may help. You might have an 80/100% toggle that's not on '14+ US Leafs.

I found https://www.youtube.com/watch?v=xZaPaTqVAls. I haven't verified its accuracy. I'm guessing you have a JDM import?
 
rasgaroo said:
A guy at a local not-so-authorized nissan service center :) . His reasoning was like that there is a bunch of things the car needs to do with the battery circuit when it is about to stop charging, and if you stop charging without 'informing' the car first, the car wouldn't have enough time to do all those things, which can eventually be bad for the battery. It's fairly possible that he made it up on the spot! :)

This may be true in a very superficial way but the connection to the car's charger is AC and there is an AC to DC converter inside that buffers the battery from the power connection. And yes, there are probably things this charging circuit needs to do in sequence to terminate the charge. I'm an EE but not an expert on high power chargers but my best guess is that this sequence of steps would probably take a matter of msec's (1000th's of a second) to execute. There is no harm to stopping charging by pressing the lock lever. Flipping the breaker is a much, much worse option and honestly, if it were me, I'd replace that breaker just as a precaution.
 
You are worrying needlessly about the state of charge. As long as you don't have the car sitting around, particularly in the heat, at 100% SOC then you're good. I personally wouldn't worry about my LEAF sitting for days at 80% SOC or less, I doubt it does any harm to the pack.
 
alozzy said:
You are worrying needlessly about the state of charge. As long as you don't have the car sitting around, particularly in the heat, at 100% SOC then you're good. I personally wouldn't worry about my LEAF sitting for days at 80% SOC or less, I doubt it does any harm to the pack.
You're in a mild climate that is perfect for Leaf batteries.

Notice the OP's sig says "Lives in a tropical country (temp. around 85F/30C)." I suspect that is the kind of temp he sees year round. Some places don't cool down much at all nor at night. That isn't good for Leaf batteries.

(Not that the OP is in Singapore, but Google for singapore average weather for an example of constantly warm. Average high temps all year are no lower than 87 F (31 C) and average low temps are no lower than 76 F (25 C).)
 
That does make a difference. I still don't understand why anyone who lives in a hot climate chooses a LEAF in the first place, but to each his/her own I guess.
 
I found one of the OP's old posts at https://mynissanleaf.com/viewtopic.php?f=27&t=31173&p=586798#p586798 that says
"Note: I live in the tropics. We don't have seasons. It's always around 80 - 86 degrees (27C - 30C). All leaf cars here show exactly 6 temperature bars all the time."
 
I don't think 86F counts as hot in Arizona. That's sweater and heavy Jeans weather.

True tropics where its 80-90F and on an island is perfect Leaf Gen 1 space. Rarely need to go more than 50 miles unless your are a cab, in which case buy a Gen 2 Leaf.
 
DougWantsALeaf said:
I don't think 86F counts as hot in Arizona. That's sweater and heavy Jeans weather.

True tropics where its 80-90F and on an island is perfect Leaf Gen 1 space. Rarely need to go more than 50 miles unless your are a cab, in which case buy a Gen 2 Leaf.
In terms of the temps, they are pretty terrible for gen 1 Leaf. We've heard of bad degradation in Hawaii on gen 1 Leaf.

My guess is because instead of having only 3-5 months of warm weather and where it does cool down at night (like in my city), it's all year round. The Leaf battery never gets a chance to cool down at all and thus degrades badly.

For example, in my city, even on hot days (e.g. 90 F or more), it is almost unheard of to have stretches of even 2 days where the low temp for the day is 70 F or more. It'll cool down to below 70 F. For my city this week, it's forecasted to hit highs of mid-80F and lows of between 59 and 63 F. I can move my Leaf outside overnight to get the battery cooler. In the morning, when I move it into the garage, batt might be between 65 and 72 F per Leaf Spy.

And, per Google, the coldest month for me is Dec with average high of 59 F and average low of 42 F.

All of the above is in impossible in a place where the low temp is 80 F, at best.

But yes, Arizona is crazy hot with many months of highs of above 100 F every day and lows of no lower than 80ish or 90ish F. But, they eventually have cooler months too. Google for phoenix average weather then click on all months to see what I'm talking about vs. honolulu average weather. And again, we've seen bad degradation in HI.
 
I remember spending time in Singapore and the temp at night is about the same as the temp during the day. The humidity is also about the same and the only real difference is the sun. So I'd expect a Leaf battery in Singapore to stay at a constant 90+ F unless it spent a lot of time in a AC cooled garage in which case the owner could probably afford a new one every year, even with Singapore's $$$$$$ taxes on cars.
 
goldbrick said:
I remember spending time in Singapore and the temp at night is about the same as the temp during the day. The humidity is also about the same and the only real difference is the sun. So I'd expect a Leaf battery in Singapore to stay at a constant 90+ F unless it spent a lot of time in a AC cooled garage in which case the owner could probably afford a new one every year, even with Singapore's $$$$$$ taxes on cars.
Indeed. Cars are CRAZY expensive in Singapore due to the (from what I understand) their certificate of entitlement crap. https://insideevs.com/news/349462/nissan-leaf-arrives-in-singapore/ is probably right. Looks like Leaf didn't arrive there until 2019.
 
It's not as hot as in Singapore, but close. At night the temperature goes down to around 75 - 80 degrees. In the midday, it's around 82 - 86 degrees. I have never seen a leaf here that is lower or higher than 6 bars.

For some reason, probably because of the wolf and lizard battery packs, 2014 and 2015 leafs do much better around where I live. I have never seen a 2013 leaf around here that has higher than 5 battery bars these days. Almost all 2014/2015 cars still have around 8 - 11 bars.
 
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