The very best battery has proven to be the IKEA LADDA.
On some aspect there are batteries like the Duracell that are technically slightly better than the Ladda but looking at the price of them being 3x that of the Ladda... well that speaks for itself.
Well the Ladda may be the best right now but battery technology is booming as energy is one of our four basic needs besides oxygen, water and food. Tomorrows batteries may be better but todays won't degrade by tomorrows invention. Keep this in mind as you won't ever buy batteries anymore while waiting for tomorrows newest and finally ending up with nothing. That being said I wrote this article to get you started in your personal search for what is the best at the time of your search. That is why I don't link to brands sites, you will find links in all the YouTube videos that by the way will get outdated as well. However i will update this page when i think that there is significant news in progressing battery technology.
In order to get some facts about batteries straight I spend an evening searching for tests about these portable powerhouses. I use Panasonic Eneloop Pro NiMH AA and AAA types as they are supposed to hold their charge longest and also last longest. But... they also are quite expensive.
Then I stumbled upon a video that there are not only fakes for sale but also that it seemes that IKEA sells them under their own brand as LADDA. Now here it gets interesting and I mean like REALY interesting!
After having studied some ten different tests on NiMH batteries and the newest Li-Ion batteries (yes in AA size!) I found out that technically the Li-Ion are supposed to be the most interesting to me. They should be capable of functioning all the way down to -20 degrees celcius but they are very expensive and have a limited charge useable. So... not realistic (yet!). On the other hand, the Li-Ions in my cameras do function very well under cold circumstances but that is probably because the camera fires a lot and thus the battery warms up.
NiMH are supposed not to function well or not at all below zero degrees Celcius. I have been using them in walky-talkies however in subzero environments though I keep them in my jacket which protects them from the low temps.
So what is so interesting about the IKEA LADDA battery? Well to cut a very long and technical story short they are marginally less good than the better Duracell and in some situations even better than the Panasonic Eneloop Pro BUT... Where those cost between €19 - €24 for four batteries the IKEA LADDA cost only €7!!! And all three have a minimum capacity of 2.450 mAH which they actually deliver! Add to that the LADDAs ability to retain its charge the best of the three (nearly to exactly 100% over a full year) and the LADDA is the absolute winner.
Then there is one more thing: the Panasonic Eneloop (not Pro) with the lesser capacity of 1.900 mAH can be recharged many more times and should be able to withstand temperatures of -20 degrees Celcius. I did not find any tests on this aspect but as the LADDA shows so many likeness with the Eneloop I suspect the LADDA 1.900 to be equally good at this point as well.
So I guess IKEA is making a very low (if any) profit on these batteries just to preserve the environment. Did you notice that they do not sell Alkaline batteries anymore? I will try to extend this information if I find any more and publish it on my website in the Workshop section.