Samsung INR21700-50S vs 50G: which cell to choose for your pack
Samsung SDI makes two 5000 mAh 21700 cells that look interchangeable at first glance but are built for different jobs: the INR21700-50S and the INR21700-50G. Both share the same format, capacity and original grade-A quality, so the right question isn't "which one is better" but which one fits your build. In this guide we compare them with real data so you get it right the first time.
What they have in common
Before the differences, it's worth pinning down what they share, because it's a lot:
- 21700 format (21 × 70 mm), the standard that has replaced the 18650 in modern packs thanks to its better capacity-to-cost ratio.
- 5000 mAh nominal capacity.
- Li-ion NMC chemistry and a 3.6 V nominal voltage (4.2 V max · 2.5 V min).
- Made by Samsung SDI, original grade-A cell (not recycled or second selection).
The difference lies in how Samsung has tuned the internal chemistry: one prioritises power (discharge current), the other energy and cycle life.
INR21700-50S: the power cell
The Samsung INR21700-50S is designed to deliver a lot of current without overheating. It handles up to 35 A (7C) continuous discharge — a very high figure for a 5000 mAh cell — and offers 18 Wh in just 72 g.
It's the choice when the pack has to deliver power on demand:
- Powerful e-bikes, scooters and electric kick-scooters.
- Cordless tools and portable machinery.
- Fast-charging, high-power power banks.
- Robotics, drones and mods.
If your controller draws high current peaks, the 50S keeps its voltage stable under load and suffers less thermal stress, which translates into longer service life in that demanding use.
INR21700-50G: the energy and density cell
The Samsung INR21700-50G is optimised to store the most energy in the least weight and volume: 17.8 Wh in 70 g and excellent durability of 1000 cycles at 80 % depth of discharge. Its discharge current is more moderate, meant for continuous loads rather than peaks.
It's the ideal cell when what you're after is range and cost per Wh:
- Solar storage and stationary DIY packs.
- High-capacity power banks.
- E-bikes and vehicles where range matters more than acceleration.
- Any build where the criterion is "how much energy fits in the pack".
By asking less current from each cell, a well-sized 50G pack ages very slowly.
Comparison table
| INR21700-50S | INR21700-50G | |
|---|---|---|
| Capacity | 5000 mAh | 5000 mAh |
| Energy | 18 Wh | 17.8 Wh |
| Max continuous discharge | 35 A (7C) | Moderate (energy cell) |
| Weight | 72 g | 70 g |
| Cycles (80 % DOD) | > 1000 | 1000 |
| Priority | Power | Energy / cycles |
| Manufacturer | Samsung SDI · grade A | Samsung SDI · grade A |
So, which one do I choose?
The quick rule:
- Does your pack have to deliver power (acceleration, peaks, tools)? → 50S.
- Does your pack have to deliver range (solar, power bank, distance)? → 50G.
And a very common third option: if your build is demanding but you also want range, size it with more 50G cells in parallel to share the current, rather than pushing a few cells hard. The numbers almost always favour energy… unless space is the limit, where the 50S allows a more compact pack for the same power.
Three tips for your DIY pack
- Don't mix models or batches in the same pack: cells should share the same reference and, ideally, matched capacity so the BMS balances well.
- Always grade A. With lithium cells, the savings from "bargain" cells are paid back in safety and lifespan. All our Samsung cells are original grade A.
- Size the current per cell, not just the total: spread the demand across enough parallel cells and you'll keep temperatures low and cycle life high.
Already know which one you need? Both are available with stock in Spain and quantity discounts: check out the Samsung INR21700-50S (power) and the Samsung INR21700-50G (energy) in our shop. If you're unsure about your build, drop us a line and we'll help you choose.