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ebill3
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Re: Rules to charge your EV

Wed Apr 11, 2012 8:25 am

EVDRIVER wrote:
mkjayakumar wrote:
.... Charge to 100% only if you are sure you will be driving away in the next few hour.....


This is not true at all. 100% is fine even for 24 hours. Days at 100% may make a slight change over years. There is far too much concern over 100% charging and I would be far more concerned over deep discharges.
+1

4.2 volts per cell is considered the maximum safe charge for Li Ion. Nissan has set 4.1 volts per cell as the 100% charge limit.

Bill
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Stanton
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Re: Rules to charge your EV

Wed Apr 11, 2012 8:58 am

adric22 wrote:I would just like to point something out. Just because these "rules" are true, it should be worth mentioning the level of importance that should be placed on them.

For example, I have pretty much always charged my car to 100%. Since my commute is short, that means plugging the car in every evening when it has an 80% or more charge on it already, and topping it off to 100%.

However, when I got my 1 year battery report from Nissan I got 5 stars on every category except for one, which I for 4 stars on. The one with 4 stars was for "charging when the battery already has a high state of charge." According to the 4 star definition, I was well within the tolerances for the battery.
You are a perfect candidate for an 80% charge everyday; you might even be able to skip a day here and there. As general as those battery reports are, if got a 4-star rating in ANYTHING, I would take notice and stop charging to 100% from a high SOC.

I would much rather encourage people to error on the conservative side (80% charging via timer so the car doesn't sit for hours before use), especially if you plan on keeping the car and are looking for maximum battery life.
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DaveEV
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Re: Rules to charge your EV

Wed Apr 11, 2012 11:32 am

Stanton wrote:
adric22 wrote:For example, I have pretty much always charged my car to 100%. Since my commute is short, that means plugging the car in every evening when it has an 80% or more charge on it already, and topping it off to 100%.

However, when I got my 1 year battery report from Nissan I got 5 stars on every category except for one, which I for 4 stars on. The one with 4 stars was for "charging when the battery already has a high state of charge." According to the 4 star definition, I was well within the tolerances for the battery.
You are a perfect candidate for an 80% charge everyday; you might even be able to skip a day here and there. As general as those battery reports are, if got a 4-star rating in ANYTHING, I would take notice and stop charging to 100% from a high SOC.

I would much rather encourage people to error on the conservative side (80% charging via timer so the car doesn't sit for hours before use), especially if you plan on keeping the car and are looking for maximum battery life.
Exactly. Never mind that the 5-star battery report that Nissan hands out is pretty much meaningless at this point in the game. Even TickTock who has a well exampled ~10% loss in capacity gets a perfect battery report.

There's a good reason why Nissan doesn't recommend that you charge back up to 100% until you're below 80%. (Note that doing this when you know you need the range isn't an issue - just doing it regularly). Charging from 80%-100% takes 90 minutes and the bulk of the charge gets in the first 60 minutes as the charge starts tapering off after that. It's not really much trouble to hit the timer-override button 60+ minutes before your trip when you know you want a full battery.

Things will get easier when battery capacity is increased another 25%. At that point 80% charging will probably become the default and you'll have to override settings to get 100% extended range mode. Just like what Tesla Roadster owners have been doing for years now.

mksE55
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Re: Rules to charge your EV

Wed Apr 11, 2012 12:07 pm

[/quote]
This is not true at all. 100% is fine even for 24 hours. Days at 100% may make a slight change over years. There is far too much concern over 100% charging and I would be far more concerned over deep discharges.[/quote]


Well which would be better for me then, I usually drive 25-30 miles a day. So my thought was to charge every 2 days instead of daily. I usually start at 100% and get about 75 miles per charge , room to spare always GOM is usually 12-18 and at 2 bars or less occass. thoughts would be charge every other day is less charges than everyday. never got below LBW. current lowest buffer is 4 miles ,just cannot drive around for nothing to see how many miles but longest was like 78 with 6 miles left.
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DoxyLover
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Re: Rules to charge your EV

Wed Apr 11, 2012 12:54 pm

mksE55 wrote:Well which would be better for me then, I usually drive 25-30 miles a day. So my thought was to charge every 2 days instead of daily. I usually start at 100% and get about 75 miles per charge , room to spare always GOM is usually 12-18 and at 2 bars or less occass. thoughts would be charge every other day is less charges than everyday. never got below LBW. current lowest buffer is 4 miles ,just cannot drive around for nothing to see how many miles but longest was like 78 with 6 miles left.
As I understand it, two charges of 50% counts a lot less against battery life than one charge of 100%. Also, the battery likes to stay in the middle of the charge range. I expect that charging to 80% every day is a lot healthier than charging to 100% every other day.
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DaveEV
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Re: Rules to charge your EV

Wed Apr 11, 2012 1:05 pm

DoxyLover wrote:
mksE55 wrote:Well which would be better for me then, I usually drive 25-30 miles a day. So my thought was to charge every 2 days instead of daily. I usually start at 100% and get about 75 miles per charge , room to spare always GOM is usually 12-18 and at 2 bars or less occass. thoughts would be charge every other day is less charges than everyday. never got below LBW. current lowest buffer is 4 miles ,just cannot drive around for nothing to see how many miles but longest was like 78 with 6 miles left.
As I understand it, two charges of 50% counts a lot less against battery life than one charge of 100%. Also, the battery likes to stay in the middle of the charge range. I expect that charging to 80% every day is a lot healthier than charging to 100% every other day.
You are correct. In this case daily 40% charge/discharges from 80%-40% and back will be easier on the battery than every other day 100%-20%. Daily 40% charge cycles is about as good as you're going to get in terms of maximizing battery life! Not to mention you'll get better overall efficiency since you'll get more regen available by avoid SOC > 80% and charge efficiency when the charge rate tapers off towards 100%.

I don't quite get what the aversion is to plugging in every day and starting each day with 80% capacity rather than alternating between 100% and 60% every other day.

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Re: Rules to charge your EV

Wed Apr 11, 2012 1:13 pm

IBELEAF wrote:My 25 mile commute brings down the charge to 5-6 bars and I primarily charge it to 80% as soon as I get home so my car sits for 12 hours until my next commute. Now, I am thinking to let the car sit for entire night and set the timer to charge to 80% 2 hours before the commute. Anyone knows if there is any benefit in this?
I set my timer to charge 12:30-4:30am (grid friendly and L1) and my commute is 8 mi RT. I keep my battery between 4 and 8 bars most of the time and only plug in when I get below 4 bars. I am expecting to keep the car for 20+ years (the same as my other "new" car). I highly recommend this for people with shorter commutes and who don't usually have additional trips. Of course every once in a while stuff happens (like today SO unexpectedly needed the car so I came home and returned to work on my bicycle).

Reddy.
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Long: http://www.mynissanleaf.com/viewtopic.p ... al#p226115"
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planet4ever
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Re: Rules to charge your EV

Thu Apr 12, 2012 1:10 am

My rule is similar to Reddy's. I have an 80% timer in effect 7 days with an end time of 7 AM and no start time. In most cases I plug in only if I am at 5 bars or less. If I expect to be driving a long distance the next day I will plug in regardless of the number of bars. If I think I might need more than 80% I either push the override switch or start charging remotely later from CarWings. I only go to 100% a few times a month, but when I do the car typically sits at that level for 4-8 hours. That gives it a chance to do cell balancing if (as many people believe) that is only done at 100%.

[We took the car on an 85 mile each way trip to visit our granddaughter and great-grandkids last weekend. That did involve 100% charging two nights in a row.]

Ray
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mksE55
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Re: Rules to charge your EV

Thu Apr 12, 2012 5:20 am

drees wrote:
DoxyLover wrote:
mksE55 wrote:Well which would be better for me then, I usually drive 25-30 miles a day. So my thought was to charge every 2 days instead of daily. I usually start at 100% and get about 75 miles per charge , room to spare always GOM is usually 12-18 and at 2 bars or less occass. thoughts would be charge every other day is less charges than everyday. never got below LBW. current lowest buffer is 4 miles ,just cannot drive around for nothing to see how many miles but longest was like 78 with 6 miles left.
As I understand it, two charges of 50% counts a lot less against battery life than one charge of 100%. Also, the battery likes to stay in the middle of the charge range. I expect that charging to 80% every day is a lot healthier than charging to 100% every other day.
You are correct. In this case daily 40% charge/discharges from 80%-40% and back will be easier on the battery than every other day 100%-20%. Daily 40% charge cycles is about as good as you're going to get in terms of maximizing battery life! Not to mention you'll get better overall efficiency since you'll get more regen available by avoid SOC > 80% and charge efficiency when the charge rate tapers off towards 100%.

I don't quite get what the aversion is to plugging in every day and starting each day with 80% capacity rather than alternating between 100% and 60% every other day.

I would agree with this but Remember, Nissan already capped the top of the battery so truly you are not doing 100%-20%, in Reality its more like 90% to 30%. others have state the battery is 24kw and we only have access to 21kw. So if I did daily charges it would be more like 90-50% vs 90-30% every other day. Has always seemed the less abuse the longer things last. I know the battery has only so many recharge cycles before it degrades. Thoughts.
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DaveEV
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Re: Rules to charge your EV

Thu Apr 12, 2012 8:48 am

mksE55 wrote:I would agree with this but Remember, Nissan already capped the top of the battery so truly you are not doing 100%-20%, in Reality its more like 90% to 30%.
It's more like 95% to 5% from "100%" to turtle.

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