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LR521 battery equivalent and size
LR521: 1.5 V alkaline button cell, 5.8 mm × 2.15 mm, about 7 mAh (11 mWh). Same battery: AG0. Also fits: SR521SW.
1.5 Vvoltage
5.8 mmdiameter, 0.228 in
2.15 mmthick, 0.085 in
≈ 7 mAhcapacity
LR521: what to know
- At 5.8 mm it is the smallest common alkaline button cell; the silver oxide 379 is the same size.
LR521 equivalents
AG0
- 379: silver
Can I use another battery instead of an LR521?
| Battery | Size | Volts | Works? | Why |
|---|---|---|---|---|
| SR521SW | 5.8 mm × 2.15 mm | 1.55 V | Yes | Same size; silver oxide lasts longer (an upgrade). |
| SR516SW | 5.8 mm × 1.65 mm | 1.55 V | Short-term | 0.5 mm thinner: may sit loose; fine short-term. |
| SR527SW | 5.8 mm × 2.7 mm | 1.55 V | No | 0.55 mm thicker: will not fit. |
| Size 10 | 5.8 mm × 3.6 mm | 1.45 V | No | Zinc-air cells need air holes; not for sealed devices. |
What uses an LR521 battery?
- Small watches and novelties
Silver oxide version: SR521SW, about 14 mAh vs 7 mAh, steadier voltage: better for watches, calipers and thermometers.