At One Place

SR521SW battery

What replaces a SR521SW
379, SR63, SR521, SR521W, AG0, D379
1.55 V silver oxide, 5.8 × 2.1 mm (diameter × height)

The SR521SW is a single-use 1.55 V silver oxide button cell. The codes below are the same physical cell sold under different manufacturer names, and any of them will fit.

Specification

IEC designation
SR521SW
ANSI / NEDA
1191SO
Nominal voltage
1.55 V
Chemistry
Silver oxide
Size
5.8 × 2.1 mm (diameter × height)
Typical capacity
14.5 mAh
Rechargeable
No — never charge it

Codes that mean the same battery

Different manufacturers, one physical battery. Voltage, chemistry and dimensions all match.
Code Fits?
379 Yes — same cell
SR63 Yes — same cell
SR521 Yes — same cell
SR521W Yes — same cell
AG0 Yes — same cell
D379 Yes — same cell
V379 Yes — same cell
1191SO Yes — same cell
SB-AJ Yes — same cell

Codes that look close but are not

Code Why it is not a substitute
SR527SW / 319 Same 5.8 mm diameter, 2.7 mm tall. Too tall for a 379 case.

The SR521SW is a primary cell and must never be put in a charger. Charging a sealed primary battery builds gas pressure inside a can with no vent designed for it, which is how they rupture or catch fire. Rechargeable look-alikes exist for several sizes and carry different codes — check the code, not the shape.

Where it turns up

  • Very small ladies' watches
  • Slim fashion watches
  • Miniature LED lights
  • Small electronic jewellery

Common questions

What is equivalent to a SR521SW?
379, SR63, SR521, SR521W, AG0, D379, V379, 1191SO, SB-AJ — all the same 1.55 V cell under different manufacturer codes.
Can I use a SR527SW / 319 instead of a SR521SW?
Same 5.8 mm diameter, 2.7 mm tall. Too tall for a 379 case.
Is the SR521SW rechargeable?
No. It is a primary cell — charging one risks rupture or fire. Rechargeable look-alikes exist in the same size under different codes.

Related pages

Sources

  1. Official vendor product documentation — At One Place

How these figures are compiled and checked