Samsung INR21700-50S vs 50GB: which cell is better for your battery pack
Both are 21700 NMC cells in the 5 Ah class from Samsung SDI, with the same footprint and the same charge voltage. They are built to different briefs, and the one that is "better" for you is decided by how much current your pack puts through a single cell.
In short
Neither cell is better in the abstract. The 50S is the right choice when a cell has to carry more than 9.8 A continuous: it is rated 25 A without a temperature cut and 45 A with an 80 °C cut. The 50GB is the right choice when the pack stays under 9.8 A per cell and benefits from its larger top vent, thicker can wall and published 500-cycle figure.
At a glance
INR21700-50S and INR21700-50GB, side by side
Every figure in this table is traceable to a model page or a manufacturer document. Where a value is not published in the source we hold, the cell says so rather than carrying a plausible-looking number.
| Attribute | INR21700-50S | INR21700-50GB | Note |
|---|---|---|---|
| Standard discharge capacity | Typ. 5,000 mAh | Min 4,900 mAh | Two different bases: typical versus minimum |
| Rated discharge capacity | Min 4,800 mAh | Min 4,753 mAh at 1 C | Rated at different discharge rates |
| Nominal voltage | 3.6 V | 3.63 V | 0.03 V apart, no design consequence |
| Max continuous discharge | 25 A without a temperature cut | 9.8 A | The decisive row for power packs |
| Conditional / non-continuous discharge | 45 A with an 80 °C surface cut | 14.7 A non-continuous | Both figures depend on a condition |
| Standard charge current | 2.5 A, 250 mA cut-off, 150 min | 2,450 mA (0.5 C) | Comparable in practice |
| Max charge current | 10 A step, 6 A continuous | 4,900 mA, not for cycle life | 50S charges faster |
| Cycle life | ≥2,940 mAh after 250 cycles at 25 A (60%) | ≥3,802 mAh after 500 cycles (80% of rated) | Different currents and criteria |
| AC impedance | Not stated in the specification we hold | ≤14 mΩ at 1 kHz | Only the 50GB publishes a figure |
| Mass | Max 72.0 g | Max 71.0 g | Within 1 g |
| Dimensions | Height ≤70.62 mm, Ø ≤21.25 mm | Height ≤70.85 mm, Ø ≤21.50 mm | Same holder, different clearance |
| Charge temperature | 0 to 60 °C ambient | 0 to 45 °C | 50GB has the narrower window |
| Safety features | Standard vent | Top vent ≈44 mm², 0.25 mm wall, bottom vent | The 50GB is the safety-oriented variant |
| Documentation | Pending | Pending | No manufacturer data sheet on file for either |
Two cells, two different briefs
The 50S is a power cell. Its electrodes are built to move charge quickly, which is why one cell can hold 25 A continuous without a temperature cut and 45 A with the surface held below 80 °C. The cost of that capability is visible in the cycle-life table: the published figure is taken at 25 A discharge, which is the current the cell is designed to survive, not a gentle test.
The 50GB is a safety-oriented energy cell. Its headline number is 9.8 A continuous, less than half the 50S, and the engineering effort went into the can instead: a top vent of roughly 44 mm² against about 25 mm² on the 50E2, a 0.25 mm wall instead of 0.22 mm, and an added bottom vent. In a sealed enclosure, or in a pack where a venting event has to be routed away from the neighbouring cells, that is worth more than current the design never uses.
The 45 A figure has a condition attached
The 50S is rated 45 A only while the pack holds the cell surface at or below 80 °C. That is a pack-level obligation, not a cell property: if the housing cannot get heat out, the usable figure falls back to 25 A, and in a closed tool housing it can fall below that. Treating 45 A as a free rating is the most common way this cell gets misapplied.
The same logic applies in reverse to the 50GB: 14.7 A is listed as a non-continuous figure. If your load profile has peaks, the question is how long each peak lasts and what the cell temperature does during it — not what the peak column says.
The capacity numbers are not printed on the same basis
The 50S quotes 5,000 mAh typical; the 50GB quotes 4,900 mAh minimum at 0.5 C charge and 0.2 C discharge. A typical figure and a minimum figure are not the same measurement: the minimum is the floor every cell has to clear, the typical is what an average cell delivers. On a like-for-like basis the two cells are close, and the 2% difference is smaller than the spread between individual cells of the same model.
Nominal voltage is listed as 3.6 V for the 50S and 3.63 V for the 50GB, which is a difference in how the two specifications were written and tested rather than a design lever. The 50S is listed at 18.0 Wh; using the 50GB's own two figures, its energy per cell lands within a few percent of that. Neither cell changes the number of cells your pack needs.
Where the 50S is the better cell
Choose the 50S when the pack is designed around current:
- Power tools and garden equipment where a single cell sees 15–25 A continuous and higher peaks
- Light traction — e-bikes, scooters, small EVs — at a parallel count low enough that 9.8 A per cell is not enough
- Equipment that has to recharge fast: 10 A step charging against the 50GB's 4,900 mA ceiling
- Packs already built around a 25 A-class cell, where a swap to 9.8 A would derate the whole design
Where the 50GB is the better cell
Choose the 50GB when the pack is designed around safety margin and runtime:
- Storage, UPS and backup modules that run below 0.5 C and never approach 9.8 A per cell
- Portable power stations and medical carts where the enclosure is sealed and venting paths matter
- Applications with vibration or assembly compression: the 0.25 mm wall is the reason this variant exists
- Projects that need a published cycle-life figure to put in a warranty document — the 50GB has one, the 50S's is stated on a different basis
The cycle-life figures cannot be compared directly
The 50S figure is ≥2,940 mAh after 250 cycles at 25 A discharge, judged as 60% of capacity. The 50GB figure is ≥3,802 mAh after 500 cycles, judged as 80% of rated capacity. Twice the cycles and a higher end point looks like a clear win for the 50GB — but the 50S number was produced under a 25 A discharge, and a power cell cycled at 25 A is doing far harder work per cycle than an energy cell cycled at 0.5 C.
Read them as what they are: evidence that each cell meets its own duty, not a ranking. If cycle life at your actual current is the deciding factor, ask for both test conditions in writing before you choose.
Both models are still marked pending on this site
Samsung SDI does not publish downloadable data sheets for these cylindrical models in the public domain, and we hold none on file for either cell. Every figure on this page comes from specification documents in circulation that we have not been able to check against a manufacturer original, which is why both models carry the pending badge on their product pages.
What that means for a design decision
Use these numbers to shortlist, not to freeze a design. Before the first prototype, have your supplier confirm capacity, the cut-off condition behind the 25 A and 45 A ratings, and the charge-temperature window against a manufacturer document. If a figure here cannot be confirmed, we will say so rather than substitute a value.
By application
| Application | Cell that fits | Reason |
|---|---|---|
| Professional power tool | 50S | Continuous draw above 9.8 A is normal, and fast charge matters |
| E-bike / e-scooter pack | 50S | Needs 15–25 A per cell at practical parallel counts |
| Residential storage module | 50GB | Runs under 0.5 C; venting and cycle-life evidence decide |
| UPS / backup unit | 50GB | Low average current, long idle periods, sealed enclosure |
| Medical cart or instrumentation | 50GB | Moderate current, safety documentation, vibration resistance |
| Drone or high-pulse pack | 50S | Peak current dominates; thermal path must be designed for it |
Rule of thumb: if the pack needs more than 9.8 A per cell, the 50GB is out before you compare anything else. Below that, the 50GB usually wins on margin and documentation.
Questions about this comparison
Is the 50GB a drop-in replacement for the 50S?
No. It is rated 9.8 A continuous against the 50S's 25 A, so any pack designed around the 50S would be derated by the swap. The physical envelope is also slightly larger: up to 21.50 mm diameter against 21.25 mm.
Can I use the 50S where a 50E was specified?
Electrically it is the safer direction — the 50S carries more current and slightly more capacity. What changes is cost and, at high current, the thermal profile. The reverse swap, from a 25 A cell to a 9.8 A cell, is the one that can put the pack outside its rating.
Which one has the better cycle life?
The 50GB publishes 500 cycles to 80% of rated capacity; the 50S publishes 250 cycles to 60% at 25 A discharge. The test conditions differ enough that the two numbers do not rank the cells. At low current the 50GB has the stronger claim; at 25 A the 50S is the one with evidence at that current.
Do you hold manufacturer data sheets for either cell?
No. Samsung SDI does not publish downloadable data sheets for these cylindrical models, and we hold none on file, so both are marked pending. Molicel is currently the only brand on this site with original manufacturer documents behind every listed model.
Settled on a cell? Send the duty profile.
Give us the continuous and peak current, the envelope and the target cycle life. We will confirm what is obtainable and which documents travel with it.