Battery types
Every kind of battery, explained
by Joe Miller
Which battery is which, what each is best at, and what to buy for flashlights, radios, solar, cars and emergencies.
Single-use (primary) batteries
| Type | Volts | Shelf life | Best for | Watch out |
|---|---|---|---|---|
| Alkaline (AA, AAA, C, D, 9V) | 1.5 | Up to about 10 years | Remotes, clocks, flashlights | Leak caustic paste when old; remove from stored devices |
| Carbon-zinc ("heavy duty") | 1.5 | 2 to 3 years | Very low drain only | Weakest; leak easily |
| Lithium AA/AAA (lithium iron disulfide) | 1.5 | Up to about 20 years | Emergency kits, cold weather, high-drain gear | Cost more; never recharge |
| Lithium coin (CR2032 and others) | 3.0 | 10 years | Key fobs, scales, watches | Deadly if a child swallows one |
| Silver-oxide button | 1.55 | 5 years | Watches | Same swallowing danger |
| Zinc-air (hearing aid) | 1.4 | 3 to 4 years sealed; weeks once opened | Hearing aids | Starts working when the tab is pulled |
Rechargeable batteries
| Type | Volts per cell | Cycles | Best for | Watch out |
|---|---|---|---|---|
| NiMH (rechargeable AA, AAA) | 1.2 | 500 to 1,000+ | Everyday AA/AAA use; low self-discharge kinds hold charge for a year | Use a smart charger |
| NiCd | 1.2 | 1,000+ | Old tools | Toxic cadmium; mostly replaced by NiMH |
| Lead-acid, flooded | 2.0 (6 cells = 12 V) | 300 to 1,000 | Cars, cheap off-grid banks | Needs water; hydrogen gas; heavy |
| Lead-acid, AGM and gel | 2.0 | 400 to 1,000 | Boats, RVs, backup | Sealed, but still heavy; don't overcharge |
| Lithium iron phosphate (LiFePO4) | 3.2 (4 cells = 12.8 V) | 2,000 to 6,000 | Solar, RVs, trolling motors, backup power | Don't charge below freezing; needs a matching charger |
| Lithium-ion (NMC, NCA) | 3.6 to 3.7 | 500 to 1,500 | Phones, laptops, tools, e-bikes, EVs | Fire risk if damaged or badly charged |
| Lithium polymer (LiPo) | 3.7 | 300 to 500 | Drones, RC models | Swell and burn when abused |
Cycle counts are typical ranges; deeper discharges and heat shorten them.
Which should you buy?
Everyday AA and AAA
Low self-discharge NiMH and a smart charger. They pay for themselves within a year.
Emergency kit
Lithium AA/AAA: 20-year shelf life and they work in the cold.
Solar and backup power
LiFePO4: the longest life and the safest lithium chemistry.
Car and truck
The lead-acid or AGM type your vehicle calls for.
Sources
Checked November 11, 2026.