Currently I
throw
batteries out after 3 years.
As long as the wraps are in pristine condition, there is no physical damage to the battery, and as long as you don't find you're getting low battery warnings too early for your liking, you can keep using them, according to
@Mooch . He says that there is no specific number of months/years your battery will last. It's just about if it holds a charge long enough for your liking.
When should you replace a battery? | E-Cigarette Forum
Another instructive video:
One thing he mentioned on some of his videos though if a battery voltage drops to 2.5 volts or below, then he recommends replacing them. At 2.5 volts and lower, a battery starts to damage itself and can cause an internal short circuit. He mentions that if you go to 2.5 volts very briefly and recharge it slowly, that's fine. But if say you don't know how long it's been at 2.5 volts, you should just replace it.
Regarding the charger you referenced, I would be curious if it measures DC or AC internal resistance. DC internal resistance is a more useful measurement for
vaping, whereas AC internal resistance tends to be what devices typically measure. As for the max current it displays for a given battery, I would wonder how they come to that number. I know Mooch runs a number of tests while monitoring battery temperature to find a CDR. It seems like it's an involved process.
The cheapest equipment I was looking at for determining the CDR and DCIR ran several hundred dollars. Maybe if we start having fewer options for 18650 or 21700 or we have to start ripping open power packs for batteries, I will invest in the equipment to run my own tests, but until then, I am just going to rely on Mooch's battery charts and follow his general advice on when to replace a battery.
One thing I thought interesting is that you can become a Patron to Mooch through a membership and ask battery related questions and request testing:
Battery Mooch is creating battery and device tests | Patreon
Anyway, that was the result of my recent research. Just pay Mooch to do it, LOL.