With so many styles of batteries out there, and just as many manufactures to choose from, what do you use and buy? Lithium Ion (Li-Ion), Lithium Polymer (Li-Poly), Nickel Metal Hydride (NiMh) or Nickel Cadmium (NiCad)?
Well, many of the big manufactures (Canon, Nikon, Sony, Olympus & Pentax*) have made that decision for you, by only allowing proprietary style Li-Ion pack, that only fits their cameras, some have even gone as far to add in a chip that only allows you to use their batteries if you want the features, but there are always third party options... they just lack that chip.
But many cameras still have accessories that use the AA or AAA style batteries, such as flashes or wireless remotes, some cameras have a AA battery tray to fit their vertical grip, for when you run out of Li-Ion power; fewer still use only AA's as their main power source (This is where the * on Pentax fits in, only their top of the line has a Li-Ion the rest use AA's).
As far as brands go, most of the name brands offer good products, some better than others, and one stands out against the rest. I take it upon myself to buy and test most of them for myself, and at one point or another, I have used them all; Panasonic, Energizer, DigiPower, Ansmann... etc. I use a lot of flash, and while I do own a Quantum Battery to fit my flashes, I have been hooked on things in the past from the cord that runs from my belt to my flash, so I would rather not have that cord, therefore I rely heavily on the NiMh rechargeable AA's.
Over the last two years, I have become more and more reliant on one manufacture over all others, and that would be the Ansmann brand. I use them for a couple reasons:
1) Their batteries are far superior in over all life and have a 2-year warranty (over everyone elses 1 year)
2) While most chargers use the old tried and true bank charge method, the Ansmann chargers are all equipped with a processor built in, and thus by giving them an intelligent charger to work with their batteries, charging them only as much as each battery needs, and not a blanket amount.
And what about care for your batteries, and is there a right way and a wrong way to charge your batteries?
Well... first thing first, the only batteries I would invest in would be the NiMh or the Li-Ion /Li-Poly styles; none of these will exhibit the 'Memory Effect" that the older NiCad's did, so long as you do the first 3 steps correctly.
The first thing to remember, is that any of these batteries are all still chemistry based, and that they will not last forever; the longest I have ever gotten out of any of my batteries before their ability to hold a charge diminishes is about 2 to 3 years. I am just starting my third year with my first set of Ansmann's, so maybe they will last longer, but time will tell.
Even still, with the Ansmann 2 year warranty, I still buy replacement batteries every 18 months, number the set, and start putting them into circulation within my workflow. So if you have a Li-Ion battery for your Nikon or Canon, and you've had it a while, it might be time to pick up a replacement.
Now to the goods of this post... The most important thing to do for a new battery(ies), is to:
1) Fully Charge it for the first time, over night is best.
2) Fully Discharge it, after its first charge, it is almost more important to do this step, drain the battery until it does nothing anymore, play with your camera, take photos, take video (if it has that option)... then when it thinks it doesn't have enough power to do anything more, turn it off, wait 10 minutes, and turn it on again and play some more. DRAIN IT FULLY
3) Charge it fully again, and once again, over night is best
You are now free to use and abuse your NiMh or Li-Ion as you see fit, once you set in the top and bottom of the chemistry, you can do anything you want to it, and it will not change that first memory setting.
I hope this help answer any battery related questions.
Hope you have all been getting in some good photo time, I know I have.