Lithium battery charge level for optimum longevity

I believe that this has been discussed extensively on here......in various forms.
First, the system design won't let the charge go to 100% nor 0%.
Within the range that IS usable, it probably doesn't make much difference.

 

The battery will never charge to anywhere near 100% - your gauge might show full bars, but TOYOTA has engineered it to work between much lesser limits than either 0 or 100. Someone did post it a while back if you search for it - I vaguely remember it was limited to something like 80% maximum charge. And they won't discharge below about 20-25%.

Because it's carefully limited, the level of battery charge when left overnight seems not to be critical - it's sorted out better by the computer than I could possibly do it.

 

For a new Gen4 Li batt I'd be clueless.

For a aged Gen2 NiMH, I feel safer keeping some decent charge 50% into the blue lines before parking. Last week we were in the mountains trying to ski, and I noticed 2 bar Purple at the hotel after a climb. I forced charged to get a few more lines before parking overnight. Topped off full charge Green is also not too good on hot days for parking, with Gen2.

 

And I am telling you that "charge level" during periods of non-use is even LESS important that it was with NiMh.
What exactly do you think can be measured ? The impact on battery life ??
If there is a difference, within the normal operating range of storage charge, it is not SIGNIFICANT even if it is somehow "measurable".

IMHO, this is another case of OCD.

 

without knowing the specific chemistry, is it just a wag?

 

Time travel. We should know in 20 years and somebody will respond to this old thread.

 

Sparkie the Volt has over 371,000 miles on it, with over 129,000 in EV. The owner says he hasn't seen any appreciable degradation on the battery at all.

 

Confusing info, but on some Li-Ion power tools and such it's recommended that you charge the battery fully after use to store it and charge it again before the next use. When I looked into Li-Ion laptop batteries some years back, when the technology was newish, the general consensus was that Li-Ion batteries are best stored at around 50% charge.
Just my opinion, not based on any recent factual evidence, but as Li-Ion tend to hold charge better than Ni-Mh (and Ni-Cad), I would think it makes less difference what the actual state of charge was whilst resting for a few hours (or days even) as long as it's not completely flat, which the Prius can't be normally.

 

the recommendation in my pip manual for loger term storage is to drive until the wall charge is gone, and you are in the hv charge area.
i read in usa today, the worst thing you can do to your cell phone battery is let it go down below 20% charge on a regular basis.
nimh batteries seem to suffer from a hot soak, all day long, in war climates. is this true of lithium?
my ryobi lithium battery chargers keep them topped up while not in use. there is a temp sensor that prohibits charging above and below certain temps.

 

I suspect the Prius tech is even smarter than your power tools.

 

It seems like some drivers like to play the game "Are you Smarter Than a Prius?"

 

aren't we?

 

The really smart ones just drive the Prius normally and let it handle the details.
Some people seem to try to avoid having the engine turn on because they think they are smarter.

 

i would drive mine normally, if i knew what normal was.

 

Normal is 'what everybody else does.' at least, that's how it seems to me....

 

I guess you are not normal, then.

 

While we're talking about normalcy, let's not be tempted to confuse "normal" with "typical."

As for me, I go with the manual and try to park with the EV portion used up or nearly so and use the timer to charge it as close to anticipated departure time as I can. But my DeWalt 1/2" hammer drill batteries really don't seem to care. They are about four years old and will still rip your arm off if you don't watch out.