Do all flashlights slowly discharge when not in use?

3 years ago by DickPuncher to c/flashlight

I was thinking about buying a wurkkos fc11 as my first flashlight but it said they recommend untwisting it in a review to avoid making a connection so it doesn’t discharge while not in use. Do I need to worry about that with all flashlights? I was planning on keeping it in my backpack so I have it whenever.

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dmenezes 14 points 3 years ago

Mechanical switch lights like the Convoy S2+ do not have any parasitic drain. But be aware that the batteries themselves have some self-discharge, Li-Ions are the worst at something like 5 percent in the first 24 hours and then loses 1–2 percent per month. Protected Li-Ions are even worse at 4-5% per month.

If you need to keep them stored for long periods, get an AA-compatible or dual-fuel flashlight and use Eneloop batteries for rechargeables, or Lithium primaries if you don't need/want to recharge.

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unpunctual_bird 7 points 3 years ago

Li-Ions are the worst at something like 5 percent in the first 24 hours and then loses 1–2 percent per month

I still remember dealing NiCad's 10-20% per month, li-ion was some space-aged future tech dream back then

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dmenezes 4 points 3 years ago

Oh man, don't even get me started on the NiCads. My beloved old Ti58C calculator used a pack of them and it was actually what killed her :-(

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Adair21 7 points 3 years ago

To add to this, if you are going to store your Li-ion batteries for any period of time then you should charge them to 3.7v instead of a full charge. This will extend the life of the battery

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dmenezes 3 points 3 years ago

Good tip, but the OP should be aware that when at 3.7V they have only ~50% charge in them, so remember to also pack a spare or two (at the same voltage) to have the same total runtime.

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friftar 2 points 3 years ago

Worth mentioning that some chargers offer a storage option, charging to exactly 3.7V.

On a charger that doesnt have this, it can be difficult to monitor it closely enough to get that exact voltage.

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jerv 1 point 3 years ago

Li-Ions are the worst at something like 5 percent in the first 24 hours and then loses 1–2 percent per month.

Non-LSD NiMHs are far worse at ~30%/month. Thirty. Three-zero.

Despite all the adulation that borders on fanaticism, the tests I've seen on Eneloops fall short of claims. Short enough that I am of the opinion that anyone who dislikes Li-ion for self-discharge should not even think of considering Eneloops unless they are willing to admit that it's not about self-discharge and they simply dislike Li-ion. Yeah, sure, it's about double, but if something is stored long enough for that to really be a big deal then lithium primary is the only viable option.

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