Household Batteries and Chargers

Alkaline, Ni-MH or lithium coin: match the chemistry to the load

Alkaline AA and AAA cells give 1.5 V and suit low-drain jobs such as remotes, clocks and wall thermometers. Rechargeable Ni-MH cells run at a nominal 1.2 V, hold their voltage better under heavy load, and suit flashes, game controllers and toys. Capacity is quoted in mAh, and about 2,000 mAh is typical for an AA Ni-MH cell. Low self-discharge types keep most of their charge on a shelf, so they suit devices used rarely. Never mix old and new cells, or different chemistries, in one device.

Flat lithium coin cells are a separate family. A code such as CR2032 means lithium chemistry, 20 mm across and 3.2 mm thick, at 3 V. A CR2450 has the same voltage but is larger, so it will not fit a CR2032 holder, and 1.5 V button cells such as the LR44 are no substitute for a 3 V coin cell. Match the exact code printed on the old battery.

Pack sizes, charger bays and model-specific packs

Pack size is a matter of use: a 2-pack covers a single remote, while 8 or 16 cells suit a household with several controllers and a flash. For charging, a four-bay unit that accepts both AA and AAA is the practical choice, and one that monitors each bay separately treats mixed or partly used cells more gently than a charger that works in pairs. Travel kits and chargers made for phones are listed here too, so read the title.

Replacement packs for cameras, laptops and UPS units are different: they are model-specific. Match the part number or the model list in the title, then confirm voltage, capacity and connector, because a pack that looks identical can differ in cell count or plug. UPS batteries are usually sealed lead-acid blocks sized by voltage and amp-hour rating, and the terminal type must match.

Questions about Household Batteries and Chargers

Can I use rechargeable AA cells instead of alkaline?

Usually yes. Ni-MH cells run at 1.2 V against 1.5 V for alkaline, but most devices work normally. A few older gadgets with a battery gauge may show low early, and very low-drain items like clocks gain little from rechargeables.

Can a CR2450 replace a CR2032?

No. Both are 3 V lithium coin cells, but the CR2450 is wider and thicker and will not fit a CR2032 holder. Always use the code printed on the old cell, and never swap a 3 V coin cell for a 1.5 V button cell.

How do I know a replacement pack fits my camera or UPS?

Match the manufacturer's model or part number listed in the title, then confirm voltage, capacity and connector shape against your old pack. Looking similar is not enough, since different models can share a case but differ in cells and plug.