Samsung 30Q 18650 (3000mAh)

The Samsung 30Q (full reference INR18650-30Q) is one of the best-known lithium-ion cells in the 18650 format, that cylindrical format measuring 0.7 in (18mm) in diameter by 2.6 in (65mm) long found in flashlights, electronic mods and countless DIY packs. Its reputation comes down to one word: balance. Where many 18650 cells lean either towards capacity or towards discharge current, the 30Q offers both at a very solid level: 3000mAh of capacity and a 15A maximum continuous discharge.

This versatility makes it a particular favorite among users of powerful flashlights, where it offers a good runtime/brightness compromise, but also in the rebuildable vaping world (high-power mods) and for building DIY battery packs (power tools, light e-bikes, robotics). Its nominal voltage is 3.6V, standard for a lithium-ion cell, with a maximum charge voltage of 4.2V.

Physically, the 30Q comes in an unprotected Flat Top version (flat positive terminal), with no built-in protection circuit, for a minimal footprint (0.72 x 2.56 in / 18.4 x 65.0mm, about 1.7 oz / 48g) compatible with the widest range of devices and cell holders. It should be charged with a charger dedicated to 18650 lithium-ion cells, never with a standard battery charger.

Two things are worth flagging. First, the 18650 format in general, and the 30Q in particular due to its popularity, is heavily counterfeited online at low prices: it is best to buy from a specialist retailer trusted by the community rather than chase the lowest price. Second, as with any bare unprotected lithium cell, it is intended for experienced users capable of handling, transporting and charging it safely. For those who master these precautions, the Samsung 30Q remains, years after its release, one of the safe bets of the 18650 format.