Index / Shell 7.9 x 5.4 mm / SR48

SR48

SR48 — silver oxide, 1.55 V, 7.9 x 5.4 mm. Current. PR48 drops straight in, and runs 1.45 V — -6.5%, which reads low, and it is zinc air, which must breathe.

What fits the compartment, and what does not

Fit answers whether it enters the compartment. Voltage answers whether the circuit will notice. A cell that fits is not always a safe substitute.

One cell is the same size, and it is not the same voltage: PR48 runs -6.5% against this one, low enough that a calibrated instrument reads below true. Whether that matters is a question about the device, not about the cell.

Also stamped 1136SO, 309, 1137SO, 393, 1181SO, S13E

It fits the compartment, not the circuit

The only current cell of this size is the wrong voltage for it. PR48 matches 7.9 x 5.4 mm exactly and runs -6.5% against this cell's 1.55 V, which is low enough that a calibrated instrument reads below true. It goes in; whether it belongs there depends on what the device does with the difference.

What this cell can stand in for

3 designations Energizer no longer lists point at this cell as the closest thing it does list, and the voltage is not the same: the gap reaches 9.7%. The device will run, and an instrument calibrated for the old cell will read off.

Every column of a row describes the discontinued cell it names. Fit reads that way too: it says whether that cell would enter this compartment, not whether this one enters its. Voltage is measured against this cell, the same way everywhere on the page: each row shows the discontinued cell’s own voltage and how far that voltage sits from this one.

What the chemistry changes

Everything above answers size and voltage. What it cannot answer is chemistry, and 1 other kind is in play here beside the silver oxide this cell uses.

• Silver oxide holds its voltage almost flat until it is spent, which is why watches and light meters were built around it.
• Zinc air takes oxygen from the air through the holes in its face. It starts discharging the moment the tab comes off and runs down in weeks whether the device is used or not, and a sealed compartment starves it.

What a watch movement does with this cell

A quartz movement pulls a short pulse through the cell every second and reads the voltage between pulses. That is why the chemistry in this envelope matters more than the size does. Silver oxide holds 1.55 V nearly flat until it is spent.

193 is the same 7.9 x 5.4 mm in alkaline: 1.5 V against this cell's 1.55 V, -3.2%. The case cannot tell them apart; the movement can. Internal impedance 20 to 30 ohms, published by the maker. That is the figure the stepper motor pulse sees, and it rises as the cell ages. 8 cells measure close enough to compare against it in the Energizer data this site reads, and 8 of them are still listed.

• The nearest is PR48: it drops straight in and runs 1.45 V, reads off.
• By stored energy it stands 2 of 3 in its envelope, at 116 milliwatt-hours.
• Energizer files it for Asia Pacific, Europe, Latin America and North America, which is where the part is sold rather than where the cell will work.
• The maker still lists it, under 3 product lines: 309, 393 and S13E.

Drawn to scale

Every published figure

Every field the maker fills is filled for this one: 12 figures in all, from chemistry through to where it is sold.

The IEC standard writes this designation in full as SR754. That form comes from the standard, not from a record of the maker’s, which is why it is not among the markings above.

2 rows in the table are not the maker's but ours: stored energy and energy per cubic centimeter. Everything else is reproduced without change.

The number a pulse sees

Energizer publishes an impedance band of 20 to 30 ohms for SR48. It is the least quoted number on the sheet and the one that decides whether the cell can drive a pulse; 3 other published figures sit below.

The part occupies 0.26 cubic centimeters and weighs 1.1 g. Capacity and voltage together put 116 milliwatt-hours in that space. Energizer files it for Asia Pacific, Europe and Latin America.

Internal impedance

20 to 30 ohms as published. A high-impedance cell sags under a pulse and recovers between pulses, which is what a movement or a sensor sees.

Cutoff voltage

1.2 V. The published capacity is counted down to this voltage; a device that quits higher up sees less than the whole figure.

Mass against volume

1.1 g filling 0.26 cubic centimeters. When the printing has worn off, a kitchen scale separates two cells of one envelope faster than a caliper does.

Where the part is filed

Asia Pacific, Europe, Latin America and North America. That is a statement about the maker's distribution and not about where the cell works.

Is that a lot of energy?

It sits in the middle of a close field: 116 milliwatt-hours, rank 2 of 3, with the cells either side within 20% of it. In a shell this crowded the energy figure is rarely what decides the choice. Per unit of volume that is 447 mWh per cubic centimeter, denser than 74% of everything measured here.

A width the catalog keeps returning to

7.9 mm is a width this catalog keeps coming back to: 16 coins sit within half a millimeter of it, SR48 included.

8 of those ones are still listed. Its 447 milliwatt-hours per cubic centimeter sit above 74 percent of everything here that publishes both a capacity and a volume. 32 of the 82 coins share its 1.55 V exactly.

• CR1220 — the next step down by volume: 0.25 cubic centimeters against this cell's 0.26.
• BR1225 — the next step up: 0.3 cubic centimeters, 115% of this one.
• LR41 — 7.9 x 3.6 mm, 1.5 V, alkaline.
• MR41 — 7.9 x 3.7 mm, 1.4 V, mercuric oxide.

The names on the package that are not designations

SR48 answers to 1 marking outside the standard: SG5. A trade marking used by importers, not an iec designation, and no standards body stands behind any of them, which is why none is printed under Also stamped above.

• SG5 — a trade marking used by importers, not an IEC designation.
• SR754 — the same designation written out in full: the standard's long form for SR48.
• 1136SO — a manufacturer part number for SR48, not a standard designation.
• 309 — a manufacturer part number for SR48, not a standard designation.
• 1137SO — a manufacturer part number for SR48, not a standard designation.
• The maker's own catalog carries 3 product lines under it.

The cell that differs only in depth

The code says the size, so the cells that get confused with SR48 are the ones that keep its diameter and change its depth. 12 cells share this diameter at depths from 1.3 to 3.7 mm, and every one of them enters the same opening.

It stands 2 of 3 in this envelope by stored energy. On a scale the difference shows before it shows on a caliper: this one weighs 1.1 g.

• 346 — same diameter, 1.3 mm tall against this cell's 5.4: 4.1 mm shallower, which neither designation carries.
• 341 — same diameter, 1.4 mm tall against this cell's 5.4: 4 mm shallower, which neither designation carries.
• SR716W — same diameter, 1.6 mm tall against this cell's 5.4: 3.8 mm shallower, which neither designation carries.
• 193 — the same 7.9 x 5.4 mm in alkaline at 1.5 V. Identical on a caliper, different in the circuit.
• MR48 — the same 7.9 x 5.4 mm in mercuric oxide at 1.4 V. Identical on a caliper, different in the circuit.

One figure the maker does not publish

One field is empty for SR48: operating temperature. A blank means the maker publishes no figure, which is not the same as zero, and it is the reason one comparison below is missing rather than wrong.

The blanks are the same in all 4 records behind this designation, so they are the catalog's silence and not a merge losing a value. What is not missing is the envelope: 7.9 x 5.4 mm, published and checked against the designation itself.

• No operating temperature — so this page cannot tell you whether the maker claims anything at all below freezing.

Before you swap anything

Everything here is computed from published dimensions and nominal voltages. That answers whether a cell enters the compartment and whether the voltage matches on paper. It does not answer what your device does with the difference, and it cannot: a cell that fits can still be the wrong cell.

One more limit, and it is the biggest. This site reads a single manufacturer’s catalog. When a page says a designation is not listed, that means Energizer no longer offers a part under it — not that nobody makes the cell. Other makers may still sell it, and for common sizes they usually do.

A voltage difference is one relation between two cells, and this page prints it from the cell it is about — in every table on the page, including the one listing cells no longer made. A figure always belongs to the cell whose voltage is printed beside it: a cell that runs lower than this one carries a minus here, one that runs higher carries a plus, and two cells at the same nominal voltage carry zero. Meet the same pair on the other cell’s page and the sign is the other one, with the figure taken against that cell instead of this one; where the two run at the same voltage, both pages print zero. The class beside the figure is not read off that figure directly. It is decided on the gap itself, taken against the higher of the two nominal voltages, so one pair of cells gets one class whichever page you meet it on: counted from this side the boundary of the class that still runs falls at 20.0% below and 25.0% above, which is the same gap divided once by the larger nominal and once by the smaller. What genuinely differs between the two directions is the consequence, and the words carry it: a cell that runs low makes a calibrated instrument read below true, and a cell that runs high makes it read above.

3 things this site cannot see. Whether the contacts reach a shorter cell. Whether the device was calibrated for a chemistry that holds its voltage flat, which silver oxide does and alkaline does not. Whether the equipment tolerates the higher current a different chemistry can deliver. Rechargeable cells are never a drop-in for primary cells regardless of size.

Cells measured next to this one

The shell is shared across chemistries: 3 cells sit at exactly this size in alkaline, mercuric oxide and zinc air. Same hole, different insides, different discharge curve.

• MR48 — 7.9 x 5.4 mm, 1.4 V
• PR48 — 7.9 x 5.4 mm, 1.45 V
• 193 — 7.9 x 5.4 mm, 1.5 V
• 346 — 7.9 x 1.3 mm, 1.55 V
• 341 — 7.9 x 1.4 mm, 1.55 V
• SR716W — 7.9 x 1.6 mm, 1.55 V
• SR58 — 7.9 x 2.1 mm, 1.55 V

Where these numbers come from

Dimensions, voltages, chemistries and capacities are published by the manufacturer and reproduced without change. Everything else on the page is ours, computed from those figures: whether one cell fits where another sat, how far apart their voltages are, stored energy and energy per cubic centimeter, the rank within a shell, and the check of the designation against the measured size.

Fit is decided within 0.3 mm on every axis, which is the order of a contact spring's travel. Voltage classes are decided by consequence, not by roundness, and they are decided on the gap between two nominal voltages taken against the higher of the two: 2.0% or less of it is the same working voltage, 6.0% starts to matter to a calibrated instrument, and past 20.0% it is a different class altogether. Measuring the gap against the higher figure is what makes the verdict the same from either cell’s page, while the printed percentage stays counted from the cell you are reading about. Cells with identical stored energy share a rank instead of being ordered arbitrarily.

Ranking uses capacity times nominal voltage, because capacity alone is not comparable across chemistries: 150 mAh at 3 V is twice the energy of 150 mAh at 1.5 V. Neighbors are chosen by measurement and never alphabetically, because two cells filed next to each other by name usually have nothing in common. A blank in any table means the maker publishes no figure, which is not the same as zero.

Source: Energizer technical data, retrieved 1 September 2026.

Records that disagree behind this page

SR48 is assembled from 4 catalog records, and they do not agree with each other on every field. Both sides are numbered below so the disagreement can be read rather than taken on trust.

1. [1] Energizer catalog record 159, listed as 393, active in the snapshot. Technical data sheet: 393z.pdf.
2. [2] Energizer catalog record 396, listed as 309, obsolete in the snapshot. Technical data sheet: 309.pdf.
3. [3] Energizer catalog record 575, listed as 393, obsolete in the snapshot. Technical data sheet: 393.pdf.
4. [4] Energizer catalog record 947, listed as S13E, obsolete in the snapshot. Technical data sheet: s13e.pdf.

Every figure above is reproduced from those records without change; the comparisons are ours and are described on the method page. Snapshot: Energizer technical data, retrieved 1 September 2026.

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