I bought a new 18650 lithium battery.and the capacity is written on it-2000mah.I doubt it because the headlamp is power off usually after using a while. Someone talk me that the discharge cut-off voltage in the capacity test should be 2.8V. I will try this time. Wait for my news.
2000 mah in an 18650? Man, youāre getting screwed. Gotta pick up a decent cell with higher capacity from a known brand. Iām partial to Sanyo, Samsung, and Molicell, but itās also important to ensure the battery can support the current draw required by the light.
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Actually I have the EVE 18650 battery with 3100mah capacity. But I doubt this ROOFER because itās always power off while using.
And get a real charger where you can measure capacity and resistance.
You can get cheap-but-good (emphasis on cheap, though) 18650s as theyāre the usual commodity cells in solar lights, etc., but make sure you donāt get some crappy rewrap thatās only 600mAH or whatever, that practically burns up during charging.
Regarding 18650s (and LiIon in general): only buy cells from either manufacturers directly, or from known-good rewrappers. And only from trustworthy shops.
In the US I think this is the go-to (US citizens, correct me if Iām misremembering): https://www.18650batterystore.com/
In the EU I recommend nkon: https://eu.nkon.nl/
Known good manufacturers: Sony, Murata, Panasonic, LG, Samsung, Molicell, EVE
Known good rewrappers: Vapcell, Keepower
The known flashlight brands (Nitecore, Acebeam, Manker, Sofirn, Wurkkos, Lumintop and many others) are usually trustworthy too, but almost always cost more than comparable cells from the cell manufacturers or Vapcell, so I rarely recommend them. They also often lack detailed specs to determine quality.
This list might be incomplete, but it should cover the most important companies.
These cells come in various capacities - some are very high capacity but very low current, others are very low capacity but very high current. For most āaverageā flashlights a middle-ground-cell is the best, so something around 3000-3300 mAh with a couple of A of discharge rating.
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I agree. Thanks a lot. The unknown manufacturer usually give the fake capacity so they could earn the same moneyļ¼
Itās a bargain brand sold wholesale on Alibaba. If you look at the company website the wholesaler buying their 2500 mAh version of the same cell pays $1.40 per battery with a minimum order of 100 batteries. If you have a small scale and you weigh a Panasonic 3.400 mAh battery it weighs 47 grams and that is right about what the similar Samsung battery weighs. Some of the batteries with over-hyped ratings weigh as little as 30 grams. Itās a good indication the battery has less of the chemicals inside so have a lower rating. The 2000 mAh battery is now pretty common in solar lights where cost is a big factor for the manufacturer.
Yes 2.6 to 2.8 volts for the discharge cutoff is pretty standard. But I agree with other posts above. It is probably good to get a known quality cell for your headlight.