21700A Lithium-Ion Rechargeable Battery – 4.2V 5000mAh High Capacity (Made in Japan)

21700A Lithium-Ion Rechargeable Battery – Extra runtime in a 21700 cell

The 21700A is a single 21700 lithium-ion rechargeable cell with a listed 5000mAh capacity, 3.7V nominal voltage, and 4.2V full charge voltage. It is a flat-top unprotected cell sold as one piece, with no charger in the box.

In Bangladesh this size is used in 21700 flashlights, power-tool packs, and custom battery builds that already include a protection circuit or a BMS. Confirm the holder or tube is marked 21700 before you order. It will not seat in an 18650 light or holder.

Read the features below, then order if this is the cell your device is built for.

21700A Lithium-Ion Rechargeable Battery Features

• Model 21700A lithium-ion rechargeable cell
• Listed capacity 5000mAh
• Nominal voltage 3.7V
• Full charge voltage 4.2V
• 21700 form factor, 21mm diameter by 70mm length
• Flat-top terminal
• Unprotected cell, no PCB in the wrap
• Origin listed as Made in Japan
• Does not fit 18650 devices
• One cell per pack, charger not included
• 7-day replacement for manufacturing defects

Confirm the 21700 Size First

A 21700 cell is wider and longer than an 18650. Measure the tube or read the mark on the device. If the holder is 18mm class, this cell will not close the cap and should not be forced.

Use it only where the maker specified 21700. Mixing sizes is a common reason a new cell never works on arrival.

What 5000mAh Means in Daily Use

5000mAh is the capacity printed for this listing. Runtime still depends on load, heat, and how you charge the cell. A high-draw light or tool pack will empty it faster than a low-draw device.

Treat the printed figure as a planning number, not a promise of the same hours in every host.

Unprotected Flat-Top Cell

The wrap does not include a protection board. Over-charge, over-discharge, short circuit, and reverse polarity must be handled by the host or by a pack BMS. Do not drop the cell onto keys, coins, or metal tools.

Do not series or parallel unmatched cells. A pack build needs matched cells and a BMS sized for that chemistry. This listing is one loose cell, not a finished pack.

Charge With a Proper 21700 Li-Ion Charger

Use a charger made for 21700 lithium-ion cells that stops at 4.2V. Charge time depends on that charger. An 18650-only bay, a nickel-metal-hydride charger, or a USB gadget not rated for this chemistry is the wrong method.

The box does not include a charger or holder. Buy those separately if your device has no onboard charge path.

Heat, Storage, and Handling

Keep the cell off dashboards, window sills, and sealed pockets while it is charging. Store around mid-charge if you will not use it for weeks. Inspect the wrap before every charge.

Stop using a cell with a torn wrap, a dent, or a smell. Recycle damaged cells through a proper drop-off. Do not put a swollen cell back in a light or pack.

What’s in the Box

1 x 21700A lithium-ion rechargeable cell

No charger, holder, or BMS is included.

Why Buy from Gadgeterians

• Cash on Delivery across Bangladesh
• Delivery inside Dhaka in 1-2 days
• Delivery across the rest of Bangladesh in 3-4 days
• 7-day replacement for manufacturing defects

Browse more cells in the batteries collection.

People Also Ask

Does this cell fit an 18650 flashlight?

No. It is a 21700 cell, about 21mm by 70mm. An 18650 tube is smaller and will not close correctly. Confirm the device mark before you buy so you do not force a mismatch.

Is this an unprotected cell?

Yes. There is no protection board in the wrap. Use it only in a host that already protects the cell, or inside a pack with a suitable BMS. Keep metal tools away from both ends.

Can I use it in an e-bike or tool pack?

Only as part of a pack that has a matching BMS and matched cells. Do not wire a loose unprotected cell into a pack with no protection. That is a build job, not a drop-in swap.

How should I charge it?

Use a 21700 lithium-ion charger that stops at 4.2V. Charge time depends on the charger you already own. Do not use an NiMH charger or an 18650-only slot.

Is a charger included?

No. The pack is the cell only. Add a 21700 Li-ion charger if your device cannot charge the cell itself. Holders and BMS boards are sold separately.

Where can I buy it in Bangladesh?

Order from Gadgeterians with Cash on Delivery, Dhaka delivery in 1-2 days, nationwide delivery in 3-4 days, and 7-day replacement for manufacturing defects.

What is the price of the 21700A Lithium-Ion Rechargeable Battery in Bangladesh?

This lithium-ion cell is 500 BDT, available at Gadgeterians Bangladesh.