Get any kind of pre charged battery what tells you they hold the charge for a long time.
Use any charger but best is if you charge slow.
The best charger is one which can test the battery capacity.
I use the La Crosse charger since several years and it is worth the money.
Why, you ask? Because even new batteries can be already partially defect. Like my new VARTA Ready2Use.
The 2100mAh Ready2Use I got from VARTA had one dud cell. While 3 were having around 1900mAh one had only 1400mAh.
After 3 test cycles (takes about one day per cycle to test) they read 2000mAh and 1500mAh.
So I changed one package (they come in 2) and now the batteries stay in the camera for a long time while I shoot hundreds of fotos. Works like the Lithium-ion batteries, but cheaper and more easy to replace.
But also sometimes they just lie to you with the high capacity cells.
This crap went straight away back to the dealer.