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patrick0101
Posts: 368
Joined: Tue Jan 04, 2011 2:46 pm
Delivery Date: 18 May 2011
Leaf Number: 1823
Contact: Website

Battery Balancing & Topping up?

Sun Jun 05, 2011 5:38 pm

If I were to leave my Leaf plugged into the Blink for months, after the initial charge, would it ever start charging again? The batteries would have some, albeit slow, self-discharge, so would the car ever request another charging session? If so, do you know what initiates this; is it time based or SOC based?

The Magne Charger and S10EV combo that I had would run periodically when left plugged in. When the SOC dropped to 94% it would get charged back up to 100% and there were "Support" events and "Leveling" events. It it seemed like the system came on about once a day for something. The Leaf/Blink charge up and then don't do anything. It "feels" like there is something missing.
~Pat
SLe VIN 1823 reserved 4/20/10, delivered 5/18/11
1998 Chevy S10EV (Feb 2007 - May 8th 2011)
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rwherrick
Posts: 48
Joined: Sat May 14, 2011 6:30 pm
Delivery Date: 03 Mar 2011
Leaf Number: 0445
Location: San Jose, CA

Re: Battery Balancing & Topping up?

Sun Jun 19, 2011 11:41 pm

Patrick,
I don't know the answer to your question. But I do know one thing - you don't want to try what you proposed. I talked to one of the Nissan Engineers, and he said charging the battery to 100% every day (and especially keeping it full in hot weather) will definitely reduce the lifetime of the battery. He said routinely topping up to 100% charge will only give about half the battery life of using the 80% charge setting on the timer. He said "the battery is happiest when it's in the middle of its 'state of charge' range - not totally full, and not really empty." I am now only fully charging my car when I know I'm going to be making a long trip (not very often). You can read up about this effect in a lot of websites with info on lithium batteries, like "battery university" or the Wikipedia articles on lithium batteries.

- Bob

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patrick0101
Posts: 368
Joined: Tue Jan 04, 2011 2:46 pm
Delivery Date: 18 May 2011
Leaf Number: 1823
Contact: Website

Re: Battery Balancing & Topping up?

Mon Jun 20, 2011 12:53 am

Thanks Bob. That is exactly why I am asking the question. Knowing how the car behaves allows us to deal with it in the best way to maximize its life.

To be clear, I am in the "80% Club" too. The question still applies, if the car hits 80% and stops charging, will it just sit there slowly self-discharging or after hitting some low threshold would it charge back up to 80%. If it does recharge, what is the threshold (79%, 75%, 70%..)? And approximately how long would it take to get there?
~Pat
SLe VIN 1823 reserved 4/20/10, delivered 5/18/11
1998 Chevy S10EV (Feb 2007 - May 8th 2011)
4kW Solar PV '07, 12kW in '15
Oregon Electric Vehicle Association
Occasional PlugInCars.com writer
Occasional WhatDrive.us panelist
Cars with Cords blogger

GaslessInSeattle
Posts: 1566
Joined: Fri May 06, 2011 2:15 pm
Delivery Date: 29 Apr 2011
Leaf Number: 850

Re: Battery Balancing & Topping up?

Mon Jun 20, 2011 3:36 pm

my understanding is that if you put the charger on manual it will charge once and that's it, no trickle, cycling or anything. If you put it on the timer, it will try to charge once for each cycle. If you are trying to figure out how you can leave it plugged in for an extended period to keep the battery ready to go, I suppose you could charge it to 80%, let it sit for a week and see if it depletes enough in that time to make it worthwhile to set a one day a week charger that would top off to 80% (I believe that's the least frequent the Blink will allow you to charge). I do not believe that would be bad for the battery, though leaving anything like this plugged in for such a long period of time might increase your risk of a power surge/lightening storm effecting the car or something like that. Personally, I'd be paranoid to leave something like this plugged in on an automated system, unattended for prolonged periods.

g
Gasless: Silver 2012 SL, traded in for Lease on 1/13
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gbarry42
Posts: 888
Joined: Mon Jan 10, 2011 5:48 pm
Delivery Date: 06 May 2011
Location: Moonlight Beach

Re: Battery Balancing & Topping up?

Mon Jun 20, 2011 4:09 pm

They way I have the timers set, I expect the Blink would charge the car once a day. Given various situations, I've seen the following behavior. The most familiar is if the Blink resets itself, which it does often. If it's during the charge period (off peak hours) it will go into charge mode. The car thinks about this for around five seconds, then tells the Blink it's done. The Blink records a "charging session" of about 0 seconds.

I also did this with the L1 EVSE (I wanted to make sure it works since I never use it). It charged for about 5 minutes before the car told it to stop. So there's your trickle charge...

Lithium batteries have a nice low leakage. There is probably more juice being drawn off by Carwings and other stuff that isn't really "off". Even Carwings goes to sleep after 2 weeks. I believe you would need to wait a month or more before seeing a drop that would make you want to charge it back up.
And there goes the first capacity bar! At 24,000 mi on 9/9/2013.
Second bar at 30,500 mi on 2/7/2015.

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