What Batteries to Things Use: The Ultimate Device Reference Chart

Most household remotes and clocks use 1.5V alkaline cells (AA/AAA), high-drain portable electronics rely on 3.7V lithium-ion cylinders (18650/21700), and off-grid solar or UPS systems depend on 12V LiFePO4 or AGM lead-acid blocks. If you are replacing a dead cell, designing a power bank, or sizing a solar array, guessing the chemistry or voltage will result in damaged electronics or a fire hazard. This reference chart maps the exact battery specifications to the devices they power, grounded in international sizing and safety standards.

How to Read This Chart

Before selecting a replacement or designing a pack, understand what each column dictates. Chemistry determines your charge algorithm and safety profile; you cannot swap a lithium-ion charger for a lead-acid profile. Nominal Voltage is the average discharge plateau, not the fully charged voltage (e.g., a 3.7V Li-ion cell actually charges to 4.2V). Typical Capacity is measured in milliamp-hours (mAh) or amp-hours (Ah) at a standard low discharge rate. Finally, the Governing Standard references the IEC (International Electrotechnical Commission) or ANSI/UL designations that define the physical dimensions and safety testing requirements for that cell type.

Which Column Applies to Your Installation? (And Derating Rules)

When sizing a battery for a specific installation—like a 12V solar bank or a UPS backup—the Typical Capacity column is your starting point, but environmental and load factors will drastically modify that base value. If you are installing in a garage, shed, or outdoor enclosure, temperature derating is the most critical modifier.

Lead-acid batteries (AGM/Gel) suffer severe capacity loss in cold environments. According to Battery University, a standard lead-acid battery loses roughly 50% of its rated capacity at 0°C (32°F). If your chart says 100Ah, you only have 50Ah usable in freezing weather. Conversely, high ambient temperatures (above 30°C/86°F) cut the overall cycle life of lead-acid batteries in half for every 8°C increase.

Lithium Iron Phosphate (LiFePO4) handles cold discharge much better, maintaining capacity down to -20°C. However, Victron Energy's technical guidelines explicitly warn that charging LiFePO4 below 0°C causes irreversible lithium plating on the anode. If your installation experiences freezing temperatures, the chart's capacity rating only applies if your Battery Management System (BMS) includes low-temperature charge disconnects or internal heating elements.

For high-drain devices like flashlights or RC cars, the capacity column is modified by the discharge rate. Alkaline cells exhibit high internal resistance; pulling 2 Amps from a 3000mAh AA cell will yield a fraction of its rated capacity due to voltage sag. For high-drain applications, you must look past the capacity column and prioritize the chemistry's C-rate capability.

What the Table Cannot Tell You

A reference chart provides the baseline physics, but real-world bench and jobsite experience reveals the edge cases that cause projects to fail. Here is what the table leaves out:

1. C-Rate and Continuous Discharge Limits

Two 18650 cells might both list 3.7V and 3000mAh, but their internal architecture dictates their maximum safe draw. A capacity-optimized cell (like the Panasonic NCR18650B) maxes out at a 1C to 2C continuous draw (3A to 6A). A power-optimized cell (like the Samsung 25R) sacrifices capacity (2500mAh) to safely deliver 20A continuous. If you put a high-capacity, low-C-rate cell into a high-drain vape or power tool, it will overheat, vent, and potentially enter thermal runaway.

2. Physical Tolerances and Fitment

The IEC standards define baseline dimensions, but manufacturer variations exist. In the 18650 space, "button-top" cells feature a protruding positive terminal that adds 2mm to 3mm to the overall length. A flashlight designed for button-tops will not make contact with "flat-top" cells, while a laptop battery pack spot-welding jig will physically reject button-tops. Always measure the physical cavity before ordering replacements based solely on the numerical size code.

3. BMS and Charge Profile Requirements

The chart lists LiFePO4 and Li-Po, but it does not explicitly state that these chemistries require active electronic management. You can safely deep-discharge an AGM lead-acid battery down to 10.5V and recharge it with a simple constant-voltage analog charger. Doing the same to a raw lithium cell without a BMS will result in cell reversal, copper dendrite formation, and catastrophic failure. SparkFun's battery technology guide emphasizes that lithium chemistries demand strict upper and lower voltage cutoffs (typically 4.2V max and 2.5V min per cell for standard Li-ion) enforced by a dedicated BMS or protection circuit module (PCM).

Bookmark Quick-Jump: Most Queried Device Batteries

For quick bench reference, here are the exact specifications for the four most commonly replaced and queried battery formats in consumer electronics and DIY solar.

When in doubt, always verify the physical dimensions with digital calipers and check the device's PCB for voltage regulator limits before substituting a different chemistry. A 3.7V Li-ion cell will instantly fry a 1.5V alkaline circuit if swapped without a buck converter, regardless of the physical fit.