Batteries: Alkaline, Lithium, Li-ion and Lead-Acid

Chemistry decides voltage, shelf life and charging

The chemistry tells you more than the brand. Alkaline cells give 1.5 V and suit low-drain devices. Primary lithium AA cells also give 1.5 V but are lighter, perform better in cold and last for years on the shelf; CR2032 coin cells give 3 V; lithium thionyl chloride cells such as 3.6 V sizes serve meters and memory backup. Nickel-metal-hydride is 1.2 V per cell and rechargeable, and lithium-ion cells are around 3.6 or 3.7 V.

Sealed lead-acid batteries come in 6 V and 12 V blocks for alarms, lighting and backup power, rated in amp-hours. Never charge a disposable alkaline or lithium cell, and charge each rechargeable chemistry only with a charger designed for it, because the charge profiles differ. Battery packs for cordless tools may be nickel-cadmium or lithium-ion, and the pack voltage, such as 12 V or 14.4 V, must match the tool.

Capacity, size and terminals: fitting battery to device

Capacity is stated in mAh for small cells and Ah for larger ones, and higher capacity runs the device longer, provided voltage, chemistry and size are the same. A higher-capacity replacement is usually fine; a higher-voltage one is not. For packs made for a specific tool or camera, the listing names the model numbers it fits, and those are the match to rely on.

Sealed lead-acid batteries use flat tab terminals: F1 is a 0.187 inch (4.75 mm) tab and F2 is 0.250 inch (6.35 mm), and the connector on the equipment must match. Check the physical dimensions too, since two 12 V 8 Ah batteries can differ by millimeters and not fit the compartment. Shelf life matters for emergency devices, and some alkaline cells are listed with a ten-year shelf life.

Questions about Batteries: Alkaline, Lithium, Li-ion and Lead-Acid

Can I use a higher-capacity battery than the original?

Yes, if the voltage, chemistry, size and connector are the same. A higher mAh or Ah figure simply gives longer run time. Do not raise the voltage, and use the charger designed for that chemistry, since the original charger may take longer to fill a larger pack.

Alkaline or lithium AA batteries?

Alkaline is fine for remote controls, clocks and other low-drain devices. Lithium AA cells weigh less, handle cold and high-drain loads like cameras and flashlights better, and last longer on the shelf. Do not swap them for rechargeable lithium-ion cells, which have a different voltage.

What do F1 and F2 mean on a lead-acid battery?

They name the flat tab terminal size. F1 is a narrower tab, about 4.75 mm, and F2 is wider, about 6.35 mm. The connector on your equipment must match, though adapters exist. Check the listing's terminal type before choosing a replacement.