cool ty im going to get a few of eachPrimary, L91/L92 (Energizer Ultimate Lithium)
Secondary, Eneloop (or by any other wrapper from FDK Japan)
At least in AA/AAA.
Primary CR123A, I'll say Surefire first, then Energizer.
Secondary Li-ion, Keeppower would be top today, but AW are still great
Rechargeable batteries should not even be considered for this role.
Rechargeable batteries should not even be considered for this role.
i mean like easy to find batterys that have great runtime
That depends what he means by best for survival. Yes, a CR123A primary might have a 20 year shelf life, but you only get to use it once. A 18650 lithium-ion rechargeable might only last 10 years, but you get to use it hundreds of times. Plus, even if you only use it once, it will last far longer than a CR123A.
So, I'd say get some quality 18650 rechargeable lithium-ion cells (Samsung 30Q, Sony VTC6, Panasonic GA), and replace them every 5 years just to be sure. Even if you only get to use them once, they'll still last a lot longer than primary cells. And if you can recharge them somehow in the apocalypse, you're golden.
If you know the apocalypse is going to last 20 years, and you won't need any batteries until year 19 (perhaps it's sunny day&night for the first 19 years), then get some CR123A's and replace them every 5 years.
What happens if... a friend... already considered them for this role? Is it ok to use them as paper weights? Just asking for a friend.
1. An 18650 rechargeable battery is a lot larger battery than a CR123A. So yea, it will have a lot more juice while the battery is young. CR123A batteries are also lighter per volume because of chemistry and electronics in the protected cells.
2. The chemistry of a lithium ion battery along with the electronics on protected cells are not as reliable, and will not put up with the extreme weather usage (hot/cold/humid) or storage conditions (hot/cold/humid) a CR123A will.
3. You can't buy 72 packs of 18650's. Well you can do something like that if you buy bulk, but why would you want to for a battery with a several year service life unless you were reselling them? Plus it would get real expensive and why would you want that many batteries that are gonna have half their capacity, or be dead in 5 years?
Replacing CR123A stock every five years is an okay idea. but you really don't need to if they're stored under normal room temperature conditions. I have cells that are twenty years old.
amazon has some off brand cr123 for like 10 batterys for 8 bucks shiped
Yes, 18650's are twice the size, but also over twice the capacity, and about 3x the energy. In an emergency, an 18650 will last longer than two CR123a's, and if you can recharge it, you can use it again and again and again.
Just use regular flat-top 18650's. They'll store just fine in almost any condition you're likely to store them in, unless you're Yoda and live in a swamp. I doubt CR123a's would fare much better.
If you want to make sure the 18650's last as long as possible, store them at 80% charged. They'll still have more juice than two CR123a's, and you'll probably double their life. Almost zero self-discharge at that level, too.
You can buy just one 18650, and recharge it 72 times.
It's way cheaper to just buy a few 18650's every 5 years to make sure they're fresh. But they'll last 10-15 years just fine, too. I have old laptop cells, stored at 100% charge for most of their life over 10 years, and they work just fine with about 80% of their original capacity.
If stored properly, I'm sure quality 18650's will last 20 years. I'd still replace them at least every 10 years, and 5 years is better if they're really for an emergency. I wouldn't want to rely on any 20 year old battery for an emergency, regardless of its chemistry.
Yeah, it doesn't really matter what chemistry you go for, as long as you buy good quality name-brand cells.
I'd maybe suggest don't buy alkaleaks, but even they should be okay as long as you replace them every few years. You'll get some leaks even if you don't use them, but they're cheap enough that you can buy dozens and throw a few out when they leak.