these are the replacement i’ve tested and i’m using currently:
- CR2032 coin cells = 3V -> use 1x LiFePO4 + 1 battery holder
- 1x AA/AAA = 1.5V -> use one of these “battery eliminator” step down converters from USB
- 2x AA/AAA in series = 3.0V -> use 1x LiFePO4 14500/10440 + 1x AA/AAA dummy battery in series
- 3x AA/AAA in series = 4.5V -> use 1x USB alligator cable + any 5V power source (powerbank or AC charger), or 1x 18500 / 18650 li-ion 3.7V (direct replacement for a 3x AAA battery holder for flashlights)
- 4x AA/AAA in series = 6.0V -> same as 3x AAA
- 5x AA/AAA in series = 7.5V -> use an USB step up adjustable converter
- 6x AA/AAA in series | PP3 = 9V -> use an USB-C PD trigger + a compatible power source (powerbank or AC charger)
- 8x AA/AAA in series = 12V -> use an USB-C PD trigger + a compatible power source (powerbank or AC charger, less commonly supported than 9V), or an USB step up adjustable converter
alternatives i’ve considered:
- Ni-MH AA/AAA -> limited compatibility due to lower voltage (1.2V), higher self-discharge than LiFePO4
- Ni-Zn AA/AAA -> limited compatibility due to higher voltage when fully charged (1.85V), higher self-discharge than LiFePO4
- Li-ion AA/AAA-sized 1.5V with builtin USB charging -> higher self-discharge than LiFePO4 due to the builtin step down circuitry
- 1.5V stepup adapter/sleeve for Ni-HM -> higher self-discharge than LiFePO4 due to the builtin step up circuitry
- use multiple LiFePO4 in series -> risk to damage the batteries
suggested readings: