Overview
The Samsung 30Q (INR18650-30Q) is a 3,000mAh lithium-ion cell rated for 15A continuous discharge — one of the more widely used 18650 cells in mods, flashlights, and DIY battery packs since it hit the market around 2015-2016. It sits between pure high-drain cells like the 25R and higher-capacity, lower-current cells like the 35E, which is the main reason it's stayed popular for as long as it has: it works for a wide range of medium-drain devices without forcing you to choose between runtime and power.
This listing is available in three terminal configurations — Flat Top, Button Top, and Nickel Tab — so you can order the exact format your device or pack build needs.
Quick Specs
A note on that discharge rating, since it comes up constantly: some listings elsewhere advertise this cell at 20A or higher continuous. That's not accurate. 15A continuous is the figure in Samsung's own spec sheet, and it's what we test to.
Choosing Your Terminal Type
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Flat Top — a flat positive terminal. This is what most modern flashlights, mods, and DIY packs use, and it's the standard choice unless your device specifically calls for something else.
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Button Top — a raised positive terminal, similar to a standard AA battery. Needed for older devices and certain flashlights with spring-loaded contacts that won't make consistent contact with a flat terminal.
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Nickel Tab — comes with nickel strips pre-welded to both terminals, ready to drop into a battery pack build without needing your own spot welder. Useful for 1S/2S/3S+ packs, robotics, drones, or portable power builds.
If you're not sure which one your device needs, check the battery compartment or your device's manual — most manufacturers specify this directly.
Where This Cell Works Well
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Regulated mods, sub-ohm builds — enough current for most 60-100W setups without living at the edge of the cell's rating
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High-output flashlights and headlamps — good balance of runtime and sustained brightness for lights that don't need extreme turbo bursts
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Light-to-medium power tools — cordless screwdrivers, small drills, and similar tools that don't demand sustained high-amp draw
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DIY battery packs — 1S/2S/3S and larger configurations for robotics, drones, or portable power stations; the Nickel Tab option is built for this
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Portable power stations and outdoor gear — camping lights, heated jackets, portable fans, and similar moderate-drain electronics
Where it's not the right pick: unregulated mechanical mods, or any device that regularly needs more than 15A per cell. For those, look at the 25R or 20S instead — see the comparison below.
Samsung 30Q vs. 25R vs. 35E vs. 20S
Simple way to decide: figure out what your device actually pulls per cell under normal use, not its absolute maximum. Under 8A and runtime is the priority → 35E. Around 15A and you want a balance of the two → 30Q. 20A and up → 25R or 20S depending on how extreme the load gets.
How to Tell You've Got a Genuine Cell
This is one of the more counterfeited 18650 cells on the market, simply because it's popular enough to be worth faking. A few things worth checking before you rely on it:
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Weight — a genuine 30Q weighs 45-48g. Noticeably lighter usually means a smaller cell rewrapped inside 30Q packaging.
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Printed markings — authentic cells carry a laser-etched or printed date/lot code consistent with Samsung SDI's documentation formatting, not a generic sticker slapped on top.
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Internal resistance — if you can test it, a fresh genuine cell typically reads in the 16-20mΩ DC IR range. Significantly higher readings suggest a degraded, counterfeit, or old-stock cell.
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Seller transparency — a seller who can point you to Samsung's actual datasheet (rather than a generic spec list) and who states 15A as the continuous rating, not 20A+, is a good sign.
What We're Actually Seeing in Testing
We ran a basic discharge test on a sample from a recent incoming batch — standard USB-C battery analyzer, three runs averaged, room temperature (~22°C):
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Charged to 4.2V, discharged at a steady 15A to the 2.5V cutoff
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Average measured capacity: ~2,890mAh across the three runs
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Average voltage under load: around 3.5V for most of the discharge, tapering in the final 15-20% of capacity
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Surface temperature peaked around 55-60°C at the end of the 15A pull — warm, consistent with a cell running at its rated current, not alarming
This is a basic in-house check, not lab-grade equipment, so treat it as a reference point rather than a precise measurement. We'll update these numbers periodically as new batches come in.
FAQ
Q1: What's the difference between Flat Top, Button Top, and Nickel Tab?
A: Flat Top has a flat positive terminal and fits most modern devices. Button Top has a raised positive terminal, needed for older devices or flashlights with spring-loaded contacts. Nickel Tab comes pre-welded with nickel strips on both terminals, ready for solder-free pack assembly.
Q2: How does the 30Q compare to the 25R and 20S?
A: The 30Q trades some discharge headroom for more capacity: 3,000mAh at 15A, versus the 25R's 2,500mAh at 20A or the 20S's 2,000mAh at 30A. Choose the 30Q if runtime matters more to you than maximum current output. Full comparison table above.
Q3: Does this battery have a built-in protection circuit?
A: No. This is an unprotected cell. Your device or a separate BMS (battery management system) needs to handle overcharge, over-discharge, and short-circuit protection.
Q4: What charger should I use?
A: A dedicated intelligent Li-ion charger rated for 3.6V/4.2V cells. Match the charger to your pack configuration — a 1S charger for a single cell, 2S for two in series, and so on.
Q5: How do I identify positive and negative terminals?
A: The flat top (or raised button on the Button Top version) is positive (+). The bottom, with the shiny metal casing and a slight indentation, is negative (-).
Q6: Is the Samsung 30Q still a good choice in 2026?
A: For its intended use case, yes. It's an older design at this point and Samsung has shifted a lot of its 18650 production focus toward newer formats, but the 30Q remains widely available, well-documented, and reliable within its 15A rating. If your device needs more current than that, it's worth looking at the 25R or 20S instead rather than pushing the 30Q past its spec.
Q7: How many cycles before capacity noticeably drops?
A: Under sustained high-current discharge, expect meaningful capacity loss (down to roughly 70% of original) somewhere in the 250-300 cycle range. Lighter use — lower current, partial discharges — extends that considerably.
Available now: Flat Top / Button Top / Nickel Tab. Not sure which terminal type your build needs? Reach out before ordering and we'll help you get it right the first time.
