Long life battery ideas

I’m trying to spec out a long life system (1-1.5 years) that takes photos ~ 1 per day.

Right now I’m looking at a external battery pack which would keep it going and the lithium battery is just a backup.
I don’t think a solar panel would work due to it being indoor and the lighting conditions are varied.

So I thought maybe a one time use alkaline battery pack.
Right now I’m looking at using alkaline D cell in packs of 8 in series by 2-3 packs so I would end up with 12V and either use an electron or a step down to 5.2V for a boron.

Any ideas or advice on battery chemistry choices and or if this is even feasible would be greatly appreciated.

Hi @botto,

Just wondering if you have seen some of the forum posts on battery recommendations?

https://community.particle.io/search?q=battery%20recommendation