Stoaty
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Does Running Battery Very Low Affect Capacity Over Time?

I have perused as many threads as I can find, but still can't find out whether running the battery down to 2 bars or 1 bar or Low Battery warning on a regular basis has any effect on battery capacity over time. In other words, should I try to avoid these low readings the same way I avoid charging over 80% (except when necessary)? I mention this in the context of my drive from West LA to Claremont, which I expect to make about 25 weekends per year. It took 7.5 bars at 50 MPH, but may take 9 bars at 60 MPH. I may not be patient enough to make the entire 100 mile round trip at a speed that low. In that case, will it be easier on the battery to cycle 10 bars to 1 bar, or 11 to 2 bars? I can charge as soon as I reach Claremont--probably on an L2 charger--so the downhill trip home won't take as much energy.
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TonyWilliams
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Re: Does Running Battery Very Low Affect Capacity Over Time?

Stoaty wrote: be easier on the battery to cycle 10 bars to 1 bar, or 11 to 2 bars?
I don't think we know that answer, but I use the 10 to 1 method, since it's easier to charge to 80%, and there's less battery heating than charging to 90%.
Thanks,

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TEG
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Re: Does Running Battery Very Low Affect Capacity Over Time?

Those 2 choices have come up before and much speculation ensued.

One point brought up, to keep in mind, is that the bottom two bars tend to be "beefier" with recent firmware so that people are less inclined to run out. A bigger 'reserve tank' so to speak. So, I would tend to go with the 10 to 1 (instead of 11 to 2) approach. Also, as was just said, it is a lot easier to stop at 80% than 90%.

On the flip side, some say it is better to add a little extra 'just in case', so if something unforeseen happens you still make it to a charging spot. Planning to run down to your last bar puts you at risk of totally running out if something unexpected happens.
Last edited by TEG on Sun Sep 11, 2011 4:53 pm, edited 1 time in total.
Stoaty
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Re: Does Running Battery Very Low Affect Capacity Over Time?

TEG wrote:On the flip side, some say it is better to add a little extra 'just in case', so if something unforeseen happens you still make it to a charging spot. Planning to run down to your last bar puts you a risk of totally running out if something unexpected happens.
That won't be a problem, since I am going out there specifically to hike in the Mount Baldy area. The plan is to leave my Leaf to charge, and ride up to Baldy with my brother who will be coming from Redlands in his ICE car. Thanks for both replies. I think I will stick with the 10 bars -> 1 bar (or 2 bars, depending on how fast I drive) since it is easier to charge to 80%. Presumably Nissan has left enough forbidden charge area on the bottom to prevent harm to the battery.
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Herm
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Re: Does Running Battery Very Low Affect Capacity Over Time?

Stoaty wrote: but still can't find out whether running the battery down to 2 bars or 1 bar or Low Battery warning on a regular basis has any effect on battery capacity over time.
Nissan has never said, but they have talked about the 80% long life mode and the warning about too many quick charges. Operating a battery on the lower extremes of charge does increase the heat. It will be interesting when we can get a true temperature reading using the Can-bus.

I suspect that Nissan hides a safety reserve of 11% when the car shuts down in turtle mode.
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JimSouCal
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Re: Does Running Battery Very Low Affect Capacity Over Time?

Stoaty wrote:
TEG wrote:...going out there specifically to hike in the Mount Baldy area...
I have spent a great deal of time going up that hill in all kinds of weather, from the village, manker flats to hut trail or the devils backbone, and and even cross countried up an area known as "Good Canyon" named after an old fire chief. By the way, Good Canyon is very rugged, but can be used to access some areas that hold snow for late season backcountry skiing, but also there is plenty of rockfall hazard and other things that go along with being off the main tracks.

My own plan is to top off at the SCE charge in Irwinidale, and drive the LEAF for the whole deal from Santa Monica area. I think I will only need to charge once on the way up but we will see....

Back on topic, I have read in several places in the forum that the empty turtle mode still maintains a margin of charge in the battery and that going down to one keeps it in the reasonable range of battery function.
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planet4ever
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Re: Does Running Battery Very Low Affect Capacity Over Time?

My own approach, based on "numerology" without a shred of scientific evidence, is to say if 80% is a comfortably safe top, then 20% is a comfortably safe bottom. Tony's chart says 80% = ~9.5 bars and 20% = ~0.5 bars. There's your 9-bar range, so charge to 80%.

I'm willing to go to 100% occasionally, and down into LBW or VLBW occasionally, while avoiding both extremes as a routine. But one bar? No sweat.

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davewill
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Re: Does Running Battery Very Low Affect Capacity Over Time?

My approach is to charge to 80% whenever I can. I wouldn't charge higher just to avoid the lower two bars for battery life purposes, although I would do so to improve my flexibility (and avoid range anxiety). My view is that if you need to go down there, go ahead...if you have a chance to add charge (especially up to 80%) and avoid those bars, good.
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abasile
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Re: Does Running Battery Very Low Affect Capacity Over Time?

I agree with others that charging to 80% in your case would be better for battery life. There seems to be more "padding" below the bottom end of the allowable charge range than above the top end.
Stoaty wrote:... I am going out there specifically to hike in the Mount Baldy area. The plan is to leave my Leaf to charge, and ride up to Baldy with my brother who will be coming from Redlands in his ICE car.
Just a thought, but could you stay overnight in Claremont the night before, charge the LEAF, and ride up to Baldy in the LEAF? I don't think you'd have a problem getting up to the top of Baldy road on an 80% charge from Claremont.
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Stoaty
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Re: Does Running Battery Very Low Affect Capacity Over Time?

abasile wrote:Just a thought, but could you stay overnight in Claremont the night before, charge the LEAF, and ride up to Baldy in the LEAF? I don't think you'd have a problem getting up to the top of Baldy road on an 80% charge from Claremont.
It might have worked out this weekend, but generally one of my other brothers will ride with me from WLA, and he has to work Friday and wouldn't be amenable to driving out Friday evening (nor would I).
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