Mongoose wrote:
I also use a 7Dayshop battery which I find just as good as the original. I rotate mine in exactly the way John described earlier.

However, John Riley makes a very good point. Lithium Ion is a technology which it is entirely possible to get dangerously wrong, particularly in an attempt to increase capacity. Always buy your batteries from a well known and respected supplier, and personally I would avoid any cheap replacement which claims a significantly higher capacity than the original.


I would add that, unlike Nickel based batteries, Li-Ion batteries like to be kept charged. Actually I think the optimum for long term storage is supposed to be about half charge, but full charge is a lot better than none. Never allow a discharged Li-Ion battery to sit around discharged for longer than you have to.

Li-Ion cells undergo a chemical change when they become dead flat, which would make charging them again dangerous. For this reason all Li-Ion cells include a safety circuit which

1: Cuts the power before the battery is totally drained
and
2: "self destructs" the battery if it ever becomes totally flat (through self discharge from being left "flat" for a long period).

Thankfully since Li-Ion cells have a very slow self discharge rate, you'd probably have to leave them "discharged" for about 6 months to cause trouble, but better safe than sorry.

mezzanotte1 wrote:
Dont know anything about batteries, but is it wise to use the cheap non Pentax ones. I'm tempted to buy 2, so it's a genuine question.