I’m guessing there will be a lot of people this year who will need to get a new set of batteries for their gadgets. I just got myself a flash for my Nikon D90 and it took me a while looking for some Rechargeable AA batteries for it.
Here are some simple tips on how to choose the right AA/AAA batteries for your device.
Disposable vs Rechargeable NiMH batteries?
Do you know why they still manufacture a lot of disposable AA batteries when rechargeable batteries are more environment friendly? It’s because regular disposable batteries are cheap and reliable. I’ve had a number of different rechargeable AA batteries before and every time I want to bring out my old AA-powered Canon PowerShot, I always find myself recharging the batteries first.
Self-Discharge
Batteries have this thing called self-discharge rate where they would continuously loose charge even when not in use. Disposable batteries have low self-discharge rate while common rechargeable ones have high discharge rate. For a regular rechargeable battery, you would get 50% charge left after a year of storage but regular alkalines will net you around 85% charge under the same condition.
When to use regular NiMH batteries
When I say regular NiMH batteries here, they’re your typical rechargeable batteries and can have high capacities. The 2700mAh AA ones can only retain their charge in half a year in storage before you need to charge them again. This means more recharge which would lead to shorter lifespan.
You use NiMH batteries for devices that you use often that requires power for a long stretch of time. Like professional photographers who needs juice on their flash most of the time during an event. These batteries typically have high recycling time so for flash photographers, it means shorter flash readiness recovery.
Low self-discharge rechargeable batteries
Then there’s these new breed of NiMH batteries having low self-discharge. A popular brand is Sanyo and their eneloop batteries. Then there’s also the German brand Ansmann and their Max-E batteries. They’re like disposable batteries when it comes to storing charge over a long period of time but they are also rechargeable. A drawback with these batteries is that they can carry a max of 2100 mAh at the moment. 
If you’re going to use these batteries for your camera or flash, you better bring a spare set just in case. This type of rechargeable batteries are well suited for gadgets that you only use for a short amount of time before storing it again. Or devices that doesn’t require a huge draw of power like remote controls, wireless mouse, clocks, etc.
When to use disposable batteries
These batteries still provide all-around performance whether you would be using your gadget sparingly or use it to power your remote controls. But with the growing popularity of low self-discharge rechargeable batteries, I hope that people will only buy disposable AA batteries when they’re in a pinch.
