Charging - SOC level differs based on prev. discharge

[Jimmydreams]

Not being a LEAF owner I wasn't aware that the software update improved the accuracy of the bar graph. Good to know.

It didn't improve the accuracy so much as built in a larger 'reserve' buffer. Now, you're down to your last bar before you get your first warning. The last bar should already have you thinking about finding a charge, so the warnings aren't catching people off-guard any more.

[LEAFfan]

Not being a LEAF owner I wasn't aware that the software update improved the accuracy of the bar graph. Good to know.

Tony posted a really good chart on here showing the actual number of miles you have remaining depending on your speed at the time. For instance, when my guess-o-meter said '10' with one bar left (and low battery warning), I actually had 22 miles left at 38 mph. Thanks again Tony!

[Jimmydreams]

And the smiley miles 84 vs. 101 attest to that at least on the face (pun not intended) value.

What the heck are 'smiley miles'?

[davewill]

And the smiley miles 84 vs. 101 attest to that at least on the face (pun not intended) value.

What the heck are 'smiley miles'?

I think they're the guessometer reading.

Anyway, ILETRIC, The higher guessometer reading may just be the low speed drive, and the difference between 5 bars and 6 bars can be just a tiny bit of charge if the readings were close to the bar boundary. I suppose it's not impossible that you managed to get the system to charge the battery a little more that way, but I wouldn't keep doing it. The owner's manual mentions not recharging unless you run it below 80% as one way to preserve battery life.

[planet4ever]

...Have they fixed the issue with turtle mode only giving about a mile or less of range?

I would't call that broken. Turtle means "pull over now!" It's the equivalent of an ICE coughing and sputtering because fuel is running out. We already have a "very low batt" warning that means there's only a few miles left.

I agree with Dave. You get a "low battery warning", then a "very low battery warning" and finally turtle mode. Based on my experience, if you get off the freeway shortly after getting "low battery", you will have 12-15 miles left before the turtle comes on. That's about 15% of your total range, and quite adequate in my opinion. You should not count on going very far in turtle mode. It's purpose is to let you get to a safe place to stop, and that is also important.

Ray

[TonyWilliams]

Tony posted a really good chart on here showing the actual number of miles you have remaining depending on your speed at the time. For instance, when my guess-o-meter said '10' with one bar left (and low battery warning), I actually had 22 miles left at 38 mph. Thanks again Tony!

This data might help your range estimates:

Range Estimate Chart Thread

Use of the digital mile remaining "Guess-O-Meter" is futile. I recommend just covering it up with a sticker.

With the current, post April 2011 firmware in the car, the moment that the last fuel bar disappears closely corresponds to 10 miles of range remaining at 38mph, and 5 miles at 70mph.

Also, one bar remaining should closely associate with the first battery low warning, and zero bars should associate with the "very low" warning. These two warnings are based are measured "hard" values of battery power, and not on your recent previous driving, like the Guess-O-Meter numbers are.

Speed in MPH......38...50...60....70...Battery Value / Percent Charge
.............................Range in miles.................................................
Fully charged.....130..91...78....65..........281..................100%
Battery Warning...20...14...12....10..........48......................17%
Very Low Warn....10.....7.....6......5...........24......................8.5%
Turtle mode........about 1 mile...................5......................1.7%

Obviously, up hills, extreme outside temperatures (hot or cold), significant wind, snow on road, use of climate control (particularly the heater), etc, will all decrease the range estimates.

[JRP3]

So what I'm concluding here is the following: Deep discharge prevents the batt from accepting a truly full charge. And topping it off after a minor discharge does the trick. It's as if I need to do some minor driving and topping off before my 42 mile freeway commute, than just charge overnight and do the 42 miles, because I start with less SOC than with the former. I'm thinking of it as having pissed the batt off by deep (almost turtle) discharge and it's making it not properly recover from the event. And the smiley miles 84 vs. 101 attest to that at least on the face (pun not intended) value.

There are no physics of lithium battery charging to support your conclusion, what you are seeing are the vagaries of the Nissan software. Even a turtle event does not take the battery low enough to cause any issues with it's charge acceptance, though obviously you don't want to do that on a regular basis since shallow cycling is best for longevity.

[DaveinOlyWA]

running a small charge off a full battery then topping the charge and driving right away probably (at least it does with lead acid and i doubt that LI is different in this respect) creates a "float charge" situation.

this practice is not good and strongly discouraged as it is the #1 way of reduce battery longevity.

when looking at battery management, we need to look at convenience, need and cost.

your cellphone battery which is not a lot different than the Leaf batts are designed to last 300-500 charge cycles. iow, 2 years if real lucky, just over a year if normal. (now you know how cellphone companies determine upgrade cycles? )


but the biggest reason is the cellphone battery has a very small charge along with a very small cost, so longevity is not the point. so they recommend you top it off all the time or whenever convenient. it simply is not worth having a dead battery verses a $35 battery replacement. communication is simply too important.

transportation is almost as important ( i know many people who would give up their car first before their cell phone. only a few that would go the other way... pretty tough decision either way) but the logistics is different.

a dead battery in a car will almost always mean no transportation for an extended period of time. it takes an hour to replace a cellphone battery or even better get a car charger. in a car if you need 60 miles of range and your car is only doing 50 miles, you are screwed. the charging infrastructure simply aint there yet.

so battery management for longevity in a car is much more important. i think you need to realize that you can drive to work and back. you have done it several times. i would stop topping off your battery. if you are concerned about range, you are better off to time it so the battery completes charging just before you have to leave in the morning.

[TangoKilo]

As I've previously stated in other posts. The numerical mileage remaining is for entertainment purposes only. I like the term "smiley miles". The charge bars, complimented by the miles per kwh reading, give you the most accurate indication of juice left in the battery. You just have to do a little math in your head. I find this "brain exercise" slows down the onset of dementia...

My trusty LEAF is up to 2,858 miles now.... I still can't wipe that grin off my face every time I jump in a light things up!

[JRP3]

running a small charge off a full battery then topping the charge and driving right away probably (at least it does with lead acid and i doubt that LI is different in this respect) creates a "float charge" situation.

this practice is not good and strongly discouraged as it is the #1 way of reduce battery longevity.

Lithium is different and you really cannot compare the two chemistries as they operate quite differently. Frankly I'm not sure where you get the idea that taking a small charge out of a lead acid battery then quickly recharging it is a bad thing, it's exactly what every starter battery goes through in a car, and most starter batteries can last 5-10 years. Lithium lasts longest if shallow cycled in the middle of SOC, but if you charge up and then drive away it's better than charging up and letting it sit, and better than deeply discharging if you end up pushing your range.

your cellphone battery which is not a lot different than the Leaf batts are designed to last 300-500 charge cycles. iow, 2 years if real lucky, just over a year if normal. (now you know how cellphone companies determine upgrade cycles? )

My cell phone is probably 5 years old at this point, still working well. Of course I almost never let it go dead and usually don't leave it on the charger.

so battery management for longevity in a car is much more important. i think you need to realize that you can drive to work and back. you have done it several times. i would stop topping off your battery. if you are concerned about range, you are better off to time it so the battery completes charging just before you have to leave in the morning.

I'll agree with the timing but I doubt he's hurting the battery much by topping it off then driving as opposed to not topping off and discharging it more deeply. If he can do his entire drive in the middle of the SOC range and isn't deeply discharging then yes skipping the top off charge is probably better.