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All batteries especially NiCad and MiMh batteries have a set number of charges that can be expected. I’ve been repairing Streamlight’s for my department for years and I’ve always been a proponent of letting the battery discharge as much as possible before charging. That being said, if you rely on your flashlight for work, that’s not always an option. The other option is to drain the battery all the way until it turns off. Place it in the charger for at least 8-12 hours to fully charge. I’ve got batteries still in service from 2016. Treat them right and they will treat you right.
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Lithium ion cells do not have have the memory effect of NiMH and certainly not like NiCad. So no reason to cycle them. NiCad should ALWAYS be 100% cycled. NiMH can be "spruced up" to full capacity every once in a while by a discharge, full charge, full discharge, full charge cycle.
There is ZERO advantage to doing this to a modern LiIon cell. It will only wear it out faster. Maximum life will be achieved by only charging to 80% and only discharging to 20%. But for a flashlight, several hundred charges is good enough and your light will be noticably dimmer at 20% capacity. I would still fully charge.
Noone should be using NiCad for ANYTHING at this point IMO. It is outdated tech that is horrible in EVERY way. NiMH is for cells that are OK to have low capacity vs volume, where weight does not matter at all, and high voltage, charge, and discharge rates are not needed. The most recent 2000+ cycle life, low self discharge NiMH tech is perfect for your small alkaline battery replacements, but horrible for almost everything else, IMO.
My only NiMH cells at this point are AA and AAA Eneloops which have a 2,100 charge cycle life. I did a refresh cycle on the batteries that were mostly sitting in storage at the 10 year mark. Some of those were so old they were the 1,400 cycle life early gen versions. They all still performed fine.
Anything negative you might read online about the limitations of LiIon cells sitting in storage or ever needing to be cycled is generally from cell chemistries that have not been used in well over a decade. My handheld and weaponlights for LE use have been LiIon for the past decade (except for handguns where I still use 123 cells in my 7 various X300 variants). To maximize LiIon cell life, charge at 1C or less, charge when the battery and air are both at room temperature, and don't leave them on the charger after they are full.