Today I had to take a few family photographs, half way in to the shoot, Uniross 2500mah died (had been using the for over a month now). When I reached out to grab the Uniross Hybrios and put them in my camera, they ditched me again!
Though I am not 100% sure, however I think I had charged them a month or two back.
Anyways, as luck would have it, none of the batteries I had were in a charged state (didn’t charged them after using them). Thankfully I still had a pair of unopened Alkaline Duracell batteries, which I had bought in 2008 and hadn’t used them till now, as I had been saving them for such an occasion and they managed to live up to to my expectation and allowed me to continue with the shoot.
A little over 10 shots with the flash, lcd and image stabilizer (IS) in full use and still no sign of low battery warning. Happy with the performance, I have put them back in storage, hoping to utilize them again in another such emergency.
At the end of the day, what I had thought initially, was right. Best backup battery is Uniross Alkaline and one should always keep an unopened pair of it for backup, even if you are using hybrid batteries, which claims to hold their charge for up to one year.