SmarToools RB40 AA 1.5V 2600mWh Rechargeable Battery (4Pcs Set)

SmarToools RB40 AA 1.5V Rechargeable Battery (4 Pcs) — Price in Bangladesh

Most rechargeable AA batteries are NiMH cells that put out 1.2V. Alkaline batteries — the ones your devices were designed around — put out 1.5V. That gap of three tenths of a volt is why a torch looks dimmer on rechargeables, why some devices show a low-battery warning on a freshly charged cell, and why a few refuse to switch on at all.

The SmarToools RB40 is a lithium cell with a voltage regulator built inside it, and it delivers a steady 1.5V from full to nearly empty. Devices run at the brightness and speed they were designed for, for the whole life of the charge, and then stop. There is no long fade at the end.

Charges over USB-C — no charger dock required

Each cell has its own Type-C port in the side. Plug it into the same cable and adapter you use for your phone and it charges in about two hours, with an LED that blinks while charging and stays lit when it is done. There is no separate charging cradle to buy, keep or lose, which is the part most people find genuinely convenient — you can top one up from a power bank in a bag.

How much energy you actually get

Capacity here is quoted as 2600mWh (milliwatt-hours) rather than the mAh figure batteries usually advertise, and for a 1.5V lithium cell that is the more honest unit — it measures stored energy rather than charge at an unstated voltage. In mAh terms the cell holds roughly 1733mAh at 1.5V.

For comparison, a common 2000mAh NiMH rechargeable at 1.2V stores about 2400mWh. So this cell holds modestly more energy, and delivers it at the voltage your device expects. It is a meaningful improvement rather than a dramatic one, and anyone claiming these hold twice as much is comparing the numbers incorrectly.

Protection built in

Each cell carries protection against short circuit, over-current, over-charging and over-discharging. That circuitry is what makes a lithium cell in an AA form factor safe to use in ordinary household devices, and it is the reason a protected cell is worth choosing over an unbranded one.

What these suit — and what they do not

They are well matched to anything that draws steady current and suffers on 1.2V: torches, wireless mice and keyboards, remote controls, toys, digital clocks, wall clocks, electronic scales, blood-pressure monitors and game controllers. Anything you currently feed alkaline batteries and replace often is a good candidate, since each cell can be recharged hundreds of times.

Two honest caveats. Because the output stays flat and then drops, devices with a battery meter will show full almost until the moment the cell stops — you get very little warning, which takes some getting used to. And a small number of devices are calibrated specifically around a falling NiMH voltage curve; those are rare, but if a device behaves oddly on these, that is why.

In the box

Four AA cells, each independently chargeable over USB-C. Standard AA dimensions (approximately 14.5mm diameter, 50.5mm tall) so they fit normal battery compartments, at 18.2g per cell.

Backed by a 6 months replacement warranty. Order online with cash on delivery all over Bangladesh — you pay when the parcel reaches you — and a 7-day easy return if anything arrives faulty or is not as described.