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AAAs vs 18650: each has pros and cons; be aware *protected* 18650's are required $$$
Reviewed in Australia on 9 June 2022
I see people are wondering about using AAAs vs 18650s in these torches.
There's little discernible difference in brightness between using Alkaline AAAs vs NiMH AAAs vs a Lithium 18650 - though the three alkaline AAA's in series have a higher initial voltage than the NiMH AAA's or 18650: 4.8V vs 3.6 vs 4.2V, the torch circuitry appears to be (correctly) current limiting so the resulting LED power is the same. A single 18650 has up to twice the energy density of the AAA's, so will last a lot longer than the AAAs.
WARNING: the torch has NO low voltage protection, it will continue to operate and draw power from the battery down to about 2V (measured with a multimeter). That is far below the safe minimum state of discharge for a Lithium 18650. As such, if you use an 18650 it must be so-called protected from over-discharge.
If you power this torch from an unprotected 18650, you will destroy the battery when you inevitably over-discharge it.
So, pros and cons:
- batteries are cheap and readily available
- will keep operating right down to their last gasp, no concerns about damage through over-discharge (over-discharging NiMHs isn't great but not the end of the world)
- handle storage well
- environmental: depending on the amount of use, the lifetime cost of non-rechargeable disposable cells (Alkaline) may not be great - and relative to the lifetime cost of the torch itself, who knows...
- operating time is shorter than 18650's
Lithium 18650 pros:
- longer operating time
Lithium 18650 cons:
- requires protected 18650s, which are expensive