It's hard for the pricing to work out unless you know you'll use them for a while. A 48-pack of Amazon AAs is $13.29 [1]. A 16-pack of Amazon rechargable AAs is $24.99 [2]. Ignoring the cost of a charger, the rechargables won't pay for themselves unless you go through 4 recharge cycles. If you add the $14.99 charger [3] for your first order, then you need 5 cycles on all of the batteries (80 cycles total) for it to be worth it.
I would be surprised if most people don't still have a use for AA and AAA batteries in a decade. A relatively light user should manage a charge cycle every couple of years, and NiMH batteries have a useful life longer than 10 years.
I think that something you're forgetting is that, though, as you mention, self-discharge has come a long way (as has charger technology, which I'm not sure has been mentioned), that doesn't mean every single product on the market actually benefits from these advances.
A consumer need only be "burned" once to form or strengthen the perception that rechargeables are an inferior good.
Capacity for LSD AA is about 2000 mAh; capacity for higher self-discharge is about 2500 mAh.
That is lower under extremely light loads than the best alkalines, but crosses over at a bit over 12 hours constant runtime since load has a relatively small effect on NiMH capacity, but a huge effect on alkaline capacity.
> A consumer need only be "burned" once to form or strengthen the perception that rechargeables are an inferior good.
Alkalines can leak corrosive electrolyte and destroy devices. This is a fairly well-known issue, but it doesn't seem like "always use rechargeable batteries so you don't ruin your stuff" is a widespread meme among the average consumer. I wonder why that is.
It's probably safe to say that the average consumer can't be bothered with anything that isn't LSD. The fact that another option even still exists hurts the overall branding, if you will, of the product category.
> That is lower under extremely light loads than the best alkalines, but crosses over at a bit over 12 hours constant runtime since load has a relatively small effect on NiMH capacity, but a huge effect on alkaline capacity.
Then we've reached parity, assuming identical size and at least close-enough weight. Is size identical (or smaller for NiMH)? Last I handled some, weight seemed comparable.
Now that we have, take a look at when that happened. More importantly, take a look at when that happened at an affordable price point. Compare that to when NiMH first started gaining popularity and what the (price-competitive) capacities (and self-discharge rates) were then, keeping in mind that's what formed consumer perception.
Total elapsed time of product existence may not be the best metric for perception change, but it'll at least give you a starting point.
> Alkalines can leak corrosive electrolyte and destroy devices. This is a fairly well-known issue, but it doesn't seem like "always use rechargeable batteries so you don't ruin your stuff" is a widespread meme among the average consumer. I wonder why that is.
I can think of two reasons. The first is that a "fairly well-known issue" isn't a well enough known issue. Suppression of bad press (or word-of-mouth) is likely the impetus behind large battery brands replacing even fairly expensive ruined electronics when customers complain to them.
Secondly, the relative frequency of the two is vastly different. One ruined flashlight (or even Garmin or whatever) every few years (though I think it's really more like decade-plus) sticks in the memory much less distinctly than having ones TV remote stop working every week or having that same flashlight never work (because one only uses it occasionally, maybe not even monthly).
> The fact that another option even still exists hurts the overall branding
That's probably true. Unfortunately, that larger mAh number is always going to tempt people. Some heavy users do go for the higher capacity with a full understanding of the disadvantages, but that's not the majority of the market.
> Then we've reached parity, assuming identical size and at least close-enough weight.
Eneloops came out in 2005. Their capacity hasn't changed, though the service life of later versions is longer and the self-discharge is even lower. The 1000 charge cycles and 75% charge after a year of the original was entirely acceptable for consumer applications. I don't see a size difference between a 4th-generation Eneloop AAA and a random Duracell alkaline, but I don't have calipers to measure precisely. NiMH batteries are heavier than alkalines, but I suspect this is insignificant in most consumer applications. Disposable lithium batteries that can substitute 1:1 for alkalines are lighter than either, with higher capacity.
> Some heavy users do go for the higher capacity with a full understanding of the disadvantages, but that's not the majority of the market.
And there's part of your answer as to why a consumer might try rechargables and still reject them, even today: self-discharge too high.
> Eneloops came out in 2005.
So 13 years ago, whereas NiMH was 1989, or a 16 year spread. Wait at least another 3 years. Actually, wait until only LSD is readily available. Then wait the number of years until how long it will have been from then since 1989.
> I don't see a size difference between a 4th-generation Eneloop AAA and a random Duracell alkaline, but I don't have calipers to measure precisely.
The specs are probably available, but the more important question isn't whether your particular Eneloops are small enough, but if the vast majority (and AmazonBasics and if there's any other popular enough brand) are.
Tiny variations in size can not just prevent the battery from going in in the first place, but, worse, keep it from coming back out.
1. https://amzn.com/B00MNV8E0C
2. https://amzn.com/B007B9NV8Q
3. https://amzn.com/B00TOVTZ7K