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Rectangular black lithium-ion laptop battery with label showing 11.1V 65Wh

FOCUSTEC

FOCUSTEC MR90Y 11.1V 65Wh laptop battery

SKU CH-3ETQ-RXKY4

Replacement 11.1V 65Wh lithium-ion battery for Dell Inspiron 14, 15 and 17 models with built-in circuit protection

  • Battery TypeLithium-Ion
  • High-capacity 11.1V 65Wh lithium-ion cell extends runtime
  • Fits Dell Inspiron 14, 15 and 17 models including 3421, 3521, 5421, 5521
  • Replaces original part numbers MR90Y, N121Y, G35K4, MK1R0, VR7HM
  • Built-in circuit protection guards against overcharge and short circuits
  • Lithium-ion chemistry minimises leakage risk and keeps output stable

Replacement battery for Dell Inspiron 14R, 15R, 17R

This lithium-ion battery delivers 11.1V and 65Wh capacity for compatible Dell Inspiron models. It replaces part numbers MR90Y, N121Y, G35K4, MK1R0 and YGMTN across 14, 15 and 17 inch variants. The cell chemistry reduces leakage risk and provides stable output for daily mobile use. Built-in circuit protection guards against overcharge and short circuits.

Simple swap with built-in safeguards

Installation follows the standard battery bay procedure: power off, release the latch and slide the pack into place. No tools are required beyond a small screwdriver for the bottom cover on some chassis. The most common issue is forgetting to disconnect the AC adapter before removal, which can trigger a protection lock. Align the connector carefully; forcing it damages the motherboard header.

Capacity ceiling of a 6-cell lithium-ion pack

The 65Wh rating reflects the practical limit of this form factor and voltage. Runtime scales with screen brightness, CPU load and wireless activity, so heavy workloads will drain it faster than light browsing. The pack cannot exceed its designed cell count, meaning it will not match higher-capacity 9-cell options that physically protrude. Aging cells gradually lose full-charge capacity over repeated cycles.

Highlights

  • High-capacity 11.1V 65Wh lithium-ion cell extends runtime
  • Fits Dell Inspiron 14, 15 and 17 models including 3421, 3521, 5421, 5521
  • Replaces original part numbers MR90Y, N121Y, G35K4, MK1R0, VR7HM
  • Built-in circuit protection guards against overcharge and short circuits
  • Lithium-ion chemistry minimises leakage risk and keeps output stable

Specifications

Battery TypeLithium-Ion

Questions about this item

How do I confirm the 11.1V 65Wh battery is working after install?

The system should report the correct voltage and capacity in the BIOS or operating system power settings, and the laptop must run on battery alone without shutting down unexpectedly.

What comes in the package and what extra items are needed?

The box contains one MR90Y battery for Dell; no cables, tools or additional adapters are included, and none are required for installation.

Which part number matches my Dell Inspiron 14-3421 or 15-3537?

This MR90Y unit replaces Dell part numbers 0MF69, N121Y, G35K4, MK1R0 and VR7HM, covering the listed 14, 15 and 17 inch models.

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