Yes, but what if they only last you twenty-six years instead of thirty years?

(Some of the Sanyo batteries that I like are rated for up to 1500 charge cycles. So at an average of fifty charges per year, they would be good for thirty years. Actually, they would still be good after that for quite a while longer; but the capacity would have reached about 80% IIRC at 1500 charges.)

So, I suppose some people would not be living long enough to have to buy new batteries anyway.

There is also the question of acceptable losses.

If you lose 10%, but are able to fastcharge, then some of us (me included) would simply go ahead with the tradeoff and the fastcharging.

Problem is, I haven't yet been able to find graphs or other data to gauge the % losses under various conditions or fastcharge rates.

There may be losses, but they may be fairly minor.

Someone at candlepowerforums has apparently charged Sanyo Eneloops at a fast (one hour) charge rate to see how many cycles they would go through and still be good. As I understand it, the batteries were still going strong after 200 cycles. (If anyone finds this thread at CPF, please post; so far I have only heard about the results; haven't read the thread itself yet.)

I'm thinking of taking a few different types of batteries, and simply "sacrificing" one of each type to an experiment(s), to see how long they will last with a certain 15-minute charger, for example. It seems that some batteries can take faster charge rates much better than others (I already experienced that with a 1-hour charger and different batteries used in it).

Maybe repeat for a 30-minute charger.

I think these Sanyos will be okay with 1-hour charging (assuming my charger is not harder on them than the charger on the CPF thread).

The Sanyo Eneloop XX (high capacity Eneloops) may fare better, or may fare worse.

For 30-minute and 15-minute charging, I haven't yet found much good data.

This territory -- some of it at least -- is probably best navigated by direct personal testing with one's own equipment.