XTAR VC8 Charger & 8x Samsung 25R Button Top 18650 Battery Kit

What's in This Bundle

• 8x Samsung INR18650-25R, 2500mAh, Button Top
• 1x XTAR VC8 8-slot LCD USB-C charger
• USB-A to USB-C charging cable and user manual included

A complete kit for anyone running an 8-cell high-drain device or building a larger pack — eight matched, genuine 25R cells paired with a charger built specifically for handling a full set like this, with independent circuitry per slot and real capacity diagnostics.

This listing is for Button Top. Looking for Flat Top? Click here to buy: Samsung INR18650-25R Flat Top + XTAR VC8 Bundle.

Why This Pairing Makes Sense

The 25R is one of the classic high-drain 18650 cells — moderate capacity, a strong 20A continuous discharge rating, and a long track record in mods, RC applications, tools, and custom packs. Eight cells bought together as a matched set means consistent capacity and internal resistance across the whole group — the more cells you're combining into a pack, the more a single mismatched cell can drag down overall performance, so buying and verifying a matched set matters even more here than it does for smaller bundles.

The XTAR VC8 is built around eight fully independent charging circuits — XTAR describes each slot as functioning like its own small charger, so one slot's charging behavior doesn't affect the others. It also runs a genuine capacity-test (grading) mode on four of its eight slots, letting you verify real measured capacity and internal resistance rather than just trusting the printed rating — a genuinely useful check for a high-drain cell like the 25R, where mismatched internal resistance shows up fast under load.

Samsung 25R — Battery Specs

This is a genuine high-drain cell, verified against Samsung's official datasheet — not rewrapped or relabeled stock. The 25R is often run close to its current ceiling in real devices, so heat management in your build matters more here than it would with a lower-drain cell.

This listing is for Button Top. For Flat Top click here

XTAR VC8 — Charger Specs

An important note on the grading/capacity test mode: only CH1 through CH4 support the charge-discharge-recharge capacity test — the other four slots (CH5-CH8) handle standard charging only. For a high-drain cell like the 25R where internal resistance consistency matters, plan to run your eight cells through CH1-CH4 in two batches of four if you want all of them tested.

A realistic note on charge time: with all 8 slots occupied, the VC8's default charging current is 0.5A per slot (adjustable down to 0.25A if you prefer an even gentler rate) — well under the 25R's 4A max charge rating, so there's real margin here. At 0.5A, a full charge for all eight 25Rs takes roughly 5.5-6 hours. CH1 and CH8 can individually push higher current (up to 2A or 3A) if you're not using all 8 slots at once.

Where the 25R Actually Shines

• RC applications — cars, planes, and similar hobbies that need real current delivery
• Power tools and custom packs where discharge capability matters more than maximum runtime per cell
• 8-cell robotics and DIY builds needing dependable, verified current under load across a larger set

Not the ideal pick if capacity or runtime matters more to you than raw discharge current — a cell like the 30Q or 35E will serve you better in that case.

Things Worth Knowing Before You Use This Kit

• The 25R is an unprotected cell. The charger enforces its own voltage and current cutoffs, but your device still needs to handle discharge-side protection.
• Don't mix these cells with older ones you already own, even if they're also 25R — run a batch through CH1-CH4's grading mode first if you want to check consistency before combining.
• Only CH1-CH4 support capacity grading. Keep that in mind if you're planning to test all eight cells before a pack build.
• This cell runs warm at its rated ceiling. That's expected behavior for a 20A cell pushed toward that limit, not a defect — but ventilation and enclosure design in your build matter.

Frequently Asked Questions

Can all 8 cells charge at once? Yes — all 8 slots operate independently and can charge simultaneously, though the per-slot current drops to 0.5A (or less) when all 8 are occupied, compared to higher rates available with fewer slots in use.

Can this charger test the real capacity of all 8 cells? Only four at a time. CH1-CH4 support the grading (capacity test) mode; CH5-CH8 handle standard charging only. Run your first four cells through CH1-CH4, then swap in the remaining four for a second round if you want all eight tested — genuinely worthwhile for a high-drain cell where resistance mismatches show up fast under load.

Why does the 25R run hotter than lower-drain cells like the 35E? It's a direct consequence of the design trade-off — the 25R prioritizes current delivery (20A continuous) over capacity, and pushing more current through a cell generates more heat. This is expected and within the cell's rated tolerance.

Does this charger work with rechargeable AA/AAA batteries too? Yes — the VC8 automatically detects Ni-MH/Ni-Cd chemistry and applies the appropriate charging strategy alongside Li-ion cells, across sizes from AAAA up to D and C.

Is this kit protected-cell compatible? The VC8 supports protected 20700/21700 cells if you use it for those later. The Samsung 25R cells included in this bundle are unprotected bare cells, which is standard for this model.

In stock now. This bundle ships as a matched set of eight genuine Samsung 25R Button Top cells with a verified XTAR VC8 charger — independent 8-slot charging with real capacity diagnostics, ready for larger high-drain builds out of the box.