One of the great things about Li-Po batteries is their ability to hold charge, not losing capacity significantly once topped up. You can happily charge up one week and fly the next without a worry. NiMHs, of course, have been a very different story, until now that is.
 
These new Sanyo Eneloop cells mean that NiMHs have finally come of age, they don't self-discharge like other NIMHs with the makers claiming the cells retain 80% capacity after 2 years. Under load they discharge evenly and can be used 1000 times.
 
They're available from Overlander Batteries in various 2000mAh transmitter and receiver pack configurations. NiMHs prefer a fast charge so a one hour, 2-amp, fast charge is all these Eneloop packs need.
 
The four-cell Rx packs are £12.99, 5-cell £15.99, whilst the 8-cell Tx pack is £24.99. As you can see, the Tx pack has Futaba/JR and Spektrum plugs.