What's in This Bundle
- 4x Samsung INR18650-30Q, 3000mAh, Flat Top
- 1x XTAR VC4SL 4-slot LCD USB-C charger
- 1x Type-C QC3.0 fast-charge cable, storage pouch, and manual (included with the charger)
A complete kit for anyone running a 4-cell device or building a small pack — four matched, genuine 30Q cells paired with a charger that does more than just charge: it tests, monitors, and reports on each cell individually.
This listing is for Flat Top. Looking for Button Top? Click here to buy: Samsung 30Q Button Top + XTAR VC4SL 4 Bundle.
Why This Pairing Makes Sense
Four 30Qs bought together as a matched set means consistent capacity and internal resistance across the group — genuinely useful for anything running cells in series or parallel, where mismatched cells degrade pack performance faster than any single "bad" cell would on its own. Flat Top is the standard terminal type for most current devices — DIY packs, tool battery builds, and equipment that doesn't rely on spring-loaded contacts.
The XTAR VC4SL is a real step up from a basic charger: it's got an LCD display showing live voltage, current, capacity, and internal resistance per slot, plus a capacity-test (grading) mode that charges, discharges, and recharges a cell to verify its actual capacity rather than just trusting the label. For a 4-cell purchase like this, that verification capability is genuinely useful — you can confirm all four cells are performing consistently before you commit them to a build.
Samsung 30Q — Battery Specs
| Parameter |
Value |
| Brand & Model |
Samsung SDI INR18650-30Q |
| Capacity |
3,000mAh (minimum ~2,900mAh) |
| Nominal Voltage |
3.6V |
| Full Charge Voltage |
4.2V |
| Discharge Cutoff Voltage |
2.5V |
| Max Continuous Discharge |
15A |
| Terminal Type |
Flat Top |
| Protection Circuit |
None (unprotected cell) |
| Weight |
~45-48g per cell |
These are genuine cells verified against Samsung's official datasheet, not rewrapped or relabeled stock.
This listing is for Flat Top. For Button Top, click here
XTAR VC4SL — Charger Specs
| Parameter |
Value |
| Input |
Type-C, QC3.0 (9V⎓2A) |
| Charging Current (CC) |
3A×1 / 2A×2 / 1A×4 / 0.5A×4 / 0.25A×4 — steps down automatically as more slots are occupied, or can be manually adjusted within what the slot count allows |
| Charging Method |
3-stage charging (trickle → constant current → constant voltage), 4 independently monitored slots, dynamic power allocation based on input power available |
| Cut-off Voltage |
4.2V ±0.05V (Li-ion) / 1.45V ±0.1V (Ni-MH/Ni-Cd) |
| Cut-off Current |
≤120mA |
| Operating Temperature |
0°C to 40°C |
| Dimensions |
L156mm x W115mm x H35mm |
| Net Weight |
212g |
| Display |
Color LCD — press Mode to cycle between capacity, current, and internal resistance readouts per slot in real time |
| Special Modes |
Capacity/grading mode (charge → discharge → recharge cycle to verify true capacity), storage mode (charges or discharges cells to their rated storage voltage to extend battery life), standard charge mode |
| Compatible Cell Sizes |
3.6V/3.7V Li-ion: 10440, 14500, 14650, 16340, 17335, 17500, 17670, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22650, 25500, 26650, flat-top 32650. 1.2V Ni-MH/Ni-Cd: AAA, AA, A, SC, C. Supports protected 20700/21700 cells; spring-loaded slots can also fit two 32650s and two 18650s at once |
| Safety |
Reverse polarity protection (displays "Err," shows 0V, and stops automatically), auto cut-off when fully charged, multiple charge protections |
A realistic note on charge time and power supply: to get the full 1A-per-slot charging with all four bays occupied, you'll need the included QC3.0 Type-C adapter/cable (9V⎓2A) — the charger auto-adjusts current based on whatever power source it detects, so a basic 5V adapter will still work but at reduced current and longer charge times. With the QC3.0 input active, expect a full charge in roughly 3.5 hours for all four 30Qs at once.
Why the Capacity Test Mode Matters for a 4-Pack
Buying four cells at once is exactly the scenario where verifying consistency pays off. The VC4SL's grading mode runs each cell through a charge-discharge-recharge cycle and reports its actual measured capacity — so instead of just trusting that all four cells hit their rated ~2,900mAh, you can check for yourself before building them into a series or parallel pack. Cells with a wider gap during testing are worth flagging rather than mixing into a tight pack build.
Where This Bundle Actually Fits
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4-cell flashlights and lanterns — devices that take a full set of four in series or parallel
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DIY battery packs — 2S2P, 4S, or similar configurations where matched internal resistance across all four cells genuinely matters
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Power tool packs where you're testing a batch before committing to a larger build
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Anyone who wants ongoing verification — the VC4SL's grading mode is useful well beyond this initial purchase, for testing any future 18650s you pick up
Not the right fit if your device only takes two cells, or if you don't need per-cell monitoring — a simpler 2-slot charger like the XTAR MC2 covers that case at a lower price point.
Things Worth Knowing Before You Use This Kit
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The 30Q is an unprotected cell. The charger enforces its own voltage and current cutoffs, but your device still needs to handle discharge-side protection.
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Don't mix these cells with older ones you already own, even if they're also 30Q — that's exactly what the grading mode is for, if you want to check compatibility before combining batches.
-
Flat Top won't work in devices that specifically require Button Top cells — check your device's battery compartment before ordering if you're not sure which terminal type it needs.
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For full charging speed, use a QC3.0 power adapter, not just any USB-C charger — the VC4SL negotiates higher power with QC3.0 sources specifically.
Frequently Asked Questions
Can this charger really tell me if a cell is underperforming? Yes — the grading/capacity test mode charges, discharges, and recharges a cell while measuring the actual capacity delivered, rather than relying on the printed rating. It's a genuine diagnostic tool, not just a charge indicator.
Do I need to charge all four cells at once? No — each of the four slots operates independently, so you can charge one, two, three, or four cells at a time, and mix different cell sizes or even NiMH batteries across the slots if needed.
Will Flat Top cells work in my device? If your device uses spring-loaded, flat, or magnetic-style contacts without a raised positive terminal requirement, Flat Top is the correct choice. If your device specifically calls for Button Top (a raised positive terminal), you'll want that version instead.
What happens if I don't have a QC3.0 adapter? The VC4SL will still charge normally on a standard USB-C power source, just at reduced current and correspondingly longer charge times. For the fastest charging across all four slots, a QC3.0 adapter is worth using.
Is this kit protected-cell compatible? Yes, the VC4SL supports protected 21700 cells up to 79.5mm if you use it for those later. The Samsung 30Q cells included in this bundle are unprotected bare cells, which is standard for this model.
What's the difference between storage mode and grading mode? Storage mode charges or discharges a cell to its rated storage voltage to help preserve battery life during long-term storage. Grading mode runs a full charge-discharge-recharge cycle specifically to measure the cell's actual capacity.
What happens if I insert a cell backwards? The display shows "Err" for that slot and the voltage reading drops to 0 — the charger stops working on that slot automatically rather than attempting to charge. Remove the cell, check its orientation, and reinsert.
In stock now. This bundle ships as a matched set of four genuine Samsung 30Q Flat Top cells with a verified XTAR VC4SL charger — ready to test, charge, and deploy in 4-cell builds out of the box.
