yee: I knew I read all that stuff on Li-Ion long term volatile data storage batteries for a reason... though I don't think it was apparent at the time, and generally the watch cell style Li rechargeable batteries (like what is in EZ carts) have no protection/memory circuits
I have seen at least 2 people's posts in the past few weeks of b/n DSLites (I don't even think flashme was even considered before they found the problem ) where the battery only lasts a couple hours out of the box- replacing the battery has fixed it for them, as far as I know.
QUOTE said:
lookup info on lithium ion batteries, you will see that they have a "memory" for how many times they have been charged
ejx982: if you want to take the quote out of context, you are welcome to. What
I was talking about is simply this (and it is explained in the next sentence or so of the post you short-quoted): it is known that the protection circuit in my PSP battery records how many times (in a EEPROM, interfaced to the PSP through a serial I2C line) it has been charged, and will effectively disable the battery from being further used or charged after ~10,000 charges (even if it could actually last 3million on this specific battery, 10,000 is some kind of fail safe to protect their butts, I guess). It would also tracks data on max charge/discharge, if that data was skewed... short battery usage is the result. There are indeed more than a few PROM counters that have been hacked in various expensive batteries. Now THAT is memory,
nothing like NiMH memory where it is just residual chemical properties that is called "memory" from a consumer standpoint, with no actual memory storage device in the loop.
In Li-ion batteries, the chemicals/metals inside actually degrade (no longer react in the same manner producing electricity) under much different conditions than ejx982 describes.
The optimal time to charge these batteries for longer life is when it reaches "storage levels", or around 40% charge (rarely the "low" on devices, which is nominally at 20%); fully discharging them (like with a short or resistor) will make the chemicals lose their properties; storing them for longer periods at full charge (or extremely low charge, 10% or less) continues the degradation along a predictable graph, which is MUCH faster than storing them at 40%.
For the first couple charges you probably should discharge the battery until the device shuts itself down for the chips to get an accurate "log" of the power range (so it doesn't have faulty data to work with at the get-go), and every 10-20 charges after that, to keep the protection circuits and battery range stored in the internal electronics of the battery "up to date" (ie: it has data and can tell the device to shut off before the battery reaches a state that would critically deplete the chemicals inside rendering them inert, and can tell the device that "I'm full" when it reaches the top end - and can then also use that data to tell the device the current power level much more accurately).
As to hot/cold: if it is extreme heat or extreme cold, it can damage LI batteries, but these things have an amazing range of temps (especially when compared to older technologies like non-rechargeable AA batteries) which they can be stored at (not necessarily
used at) with little to no effect on the batteries chemicals.
