You use metal hydride batteries (NiMH).
In these batteries (compared to lithium) is quite high-discharge current. Unfortunately it is not treated.
Also take note — these batteries should not be stored charged (again in contrast to lithium, which on the contrary should not be stored discharged) — this reduces their service life.
How to fight self-discharge? No way. From different manufacturers and they have different self-discharge. There are successful, is very unfortunate.
For example Philips 2450mAh AA (8pcs) work for me fine, but Philips AA 2700 mAh (8pcs) — worse... the feeling that their capacity is not 2700, but 1000. And no "pumping" does not help. And with other manufacturers — have a good GP, there is a terrible — it's a dozen or two AA and AAA. Was Lenmar — good capacity if not for one thing — for one and a half years all went down (and this is 8pcs 8pcs AA and AAA).
Samsung 2700mAh (4pcs). Three work fine, one battery capacity 4 times less... marriage is a specific battery.
Sony 2500mAh — nothing bad I can not say — quite normal.
Camelion AAA 1000mAh (8pcs) — good, as well as sony — marriage was not working well.
As you can see — I buy the kits, that would not be hits in the Frank marriage of any one battery. Charging (steam home and at work) is also normal, 4 channel, where each battery is charged individually, not the heap, where it may be incomplete charging and recharging is easy.
Someone doubted the veracity because of the amount of the said batteries but it's true.
I have a lot of batteries, as a fan of these devices. Mouse (4pcs), claves, portable speakers (2pcs), pair of cameras, radio camp, a bunch of flashlights for Hiking and the like, and is all in AA or AAA (even in the radio, which is a "C" — using a special adapter for AA batteries). Therefore, the experience gained is not very small.