Li-Ion chemistry is considered, in textbooks, to have an extremely low
self discharge rate. I don't have enough personal experience under
rigorous conditions to say whether I have observed the same or not.

Bear in mind that you cannot judge this by just looking at the
"battery gas gauge" change over time - that isn't accurate enough.
Also, as was pointed out, the protection circuitry's tiny current
drain probably swamps the actual self discharge.

Sean


On Fri, Aug 27, 2010 at 12:08 AM, John Gardner <goflo3@gmail.com> wrote:
>> my LiIon cells seem to hardly lose any charge when left
> unused for 6 months to a year...
>
> Seems like the things I own that use Li-ion (cell phone, Kindle),
> need frequent recharging, independent of use, but a sample of
> one is hardly a trend line.
>
> I have some Sanyo industrial NiMH 1500 maH AAs I bought in
> 1998 that still push out 900-1000 maH. That these fellows fed
> off my LM317 1A constant-current homebrew charger for many
> of those years seems remarkable to me.
>
> I monitored cell voltage & quit at 1.50 volts, with the odd foray
> to 1.55 or so due to malfeasance. Hot days I quit sooner.
>
> Seemed to work... =A0:)
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