We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Black rectangular lithium-polymer laptop battery with 21Wh capacity

POWER-FENG

POWER-FENG K81RP 21Wh laptop battery

SKU CH-GJR4-1Y83K

21 Wh lithium-polymer replacement battery for Dell Venue 8 7840 and T02E models

  • Battery typeLaptop Batteries
  • Product typeBattery
  • Li-polymer chemistry delivers stable 3.7V output
  • 21Wh capacity provides 5780mAh runtime
  • Direct replacement for K81RP and 5PD40 part numbers
  • Fits Dell Venue 8 7840 and T02E models
  • Brand-new black battery ready for installation

Battery for Dell Venue 8 7840

This 21 Wh lithium-polymer pack replaces Dell part numbers K81RP and 5PD40. It is built for owners of the Venue 8 7840 or T02E who need a direct-fit replacement. Buyers with other Dell tablets or laptops cannot use this unit.

Sustained discharge at 3.7 V

The 5780 mAh cell delivers its rated capacity across a full discharge cycle rather than only in brief bursts. Voltage remains stable at 3.7 V during typical workloads so the tablet runs predictably until the battery is depleted.

Thermals and power draw

Li-polymer chemistry keeps heat output low during normal charging and discharging. The pack draws only the current the tablet requests, so fan noise and system thermals stay unchanged from the original battery.

How it compares

Measured against everything we stock in Laptop Chargers & Batteries, at today’s prices. Recalculated every night.

Price $32.99
Pricier than about 57% of the 27,790 comparable items (median $30.99).

Specifications

Product
Product typeBattery
Power
Battery typeLaptop Batteries

Questions about this item

Does the 3.7 V Li-polymer cell run hot during a full day of use?

The 3.7 V Li-polymer chemistry stays cool under normal load; no active cooling is required.

Which Dell models accept the K81RP part number directly?

It replaces K81RP and 5PD40 in the Venue 8 7840 and T02E tablets.

Will the 21 Wh pack fit a Venue 8 7840 that still uses its original chassis?

Yes, the K81RP is a direct mechanical and electrical match for that chassis.

More in Laptop Chargers & Batteries

Similar items