9900 mAh 18650 accumulator

[SiliconWizard]

and eBay just refunded me

Probably simpler and cheaper for Ebay in the short term, but it's not sustainable. If just a few people demand a refund it's a mere cost of doing business, but it lots of people do then they'll have to review they way they resolve these issues, and the only option open to them is to charge the vendor. So on that basis it makes sense to use Ebay even more

Yep, but I'd guess the fraction of all refund queries is low, and thus eBay doesn't care, as it's probably just background "noise" to them. Especially for cheap stuff. Many people, including myself, will not even bother (unless I'm in a very bad mood) asking for refund if I just paid a couple bucks for something... I may just leave negative feedback. More often, I even just don't bother to leave any feedback at all in these cases... the extra time it takes me being not even worthwhile compared to the price of the items.

Sure if you're willing to enforce justice you may take those extra steps (even when they are not even "economically viable"), but I frankly don't know how many of us are ready to do so...

[ESXi]

I always have a big stash of 18650 cells, all from dead or used and working laptop battery packs.

Got a 18650 charging board charged all batteries up (took me a while got like 40 batteries, mixed capacity, and brands). Did store them in a safe place, checked voltage for voltage drop and cleaned out the dead ones after a few months.

So I have only spend like 2 dollar on a charging board and some electricity for charging the batteries. Green for the environment and my wallet !