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Rectangular black lithium-ion battery pack with four cells and Dell branding

DELL

DELL M5Y1K 14.8V 40Wh 4-cell battery for Inspiron N5458 N5551 N5555 N5558 N5559 N5755 N5758

SKU CH-X7WZ-YVKQE

Replacement lithium-ion battery rated at 14.8V and 40Wh for compatible Dell Inspiron models

  • CompatibilityCompatible with Dell Inspiron N5458 N5551 N5555 N5558 N5559
  • Battery TypeLithium-Ion
  • 8 V output matches original Dell power requirements
  • 40 Wh lithium-ion capacity extends runtime between charges
  • Four premium cells deliver stable voltage under load
  • Fits Inspiron N5458 N5551 N5555 N5558 N5559 N5755 N5758
  • CE and RoHS certified for safety and environmental compliance

40 Wh 14.8 V Lithium-Ion replacement

This 40 Wh lithium-ion battery replaces the original pack in Dell Inspiron N5458 N5551 N5555 N5558 N5559 N5755 N5758 models. It uses a 4-cell design rated at 14.8 V and is supplied new with CE and RoHS certification. The unit is intended for owners of those specific laptops who need a direct swap for a worn or failed battery.

Practical limits of the lithium-ion pack

Capacity is fixed at 40 Wh and voltage at 14.8 V, so runtime will match the original specification rather than exceed it. The pack is not compatible with other Dell families or with the alternative battery variant that fits the same model numbers. No circuitry in the battery can increase the laptop's charging speed or power delivery beyond the system's own limits.

Check the original battery before ordering

Dell ships two different batteries for these model numbers and they are not interchangeable. Compare the part number and physical layout of your existing pack against the product photos to confirm the M5Y1K matches. Buyers whose original battery carries a different part code will find this unit does not fit or connect.

Highlights

  • 8 V output matches original Dell power requirements
  • 40 Wh lithium-ion capacity extends runtime between charges
  • Four premium cells deliver stable voltage under load
  • Fits Inspiron N5458 N5551 N5555 N5558 N5559 N5755 N5758
  • CE and RoHS certified for safety and environmental compliance

Specifications

CompatibilityCompatible with Dell Inspiron N5458 N5551 N5555 N5558 N5559 N5755 N5758
Battery TypeLithium-Ion

Questions about this item

How do I know which of the two different batteries for my Dell laptop is the correct M5Y1K version?

The M5Y1K fits Dell Inspiron N5458 N5551 N5555 N5558 N5559 N5755 N5758 models; compare your original battery to the product photos to confirm the exact match before ordering.

What does the 40Wh capacity mean for daily use in my Inspiron?

A 40Wh lithium-ion pack typically delivers several hours of mixed workloads such as document editing and streaming on a 14.8V system, though actual runtime varies with screen brightness and applications.

Does the 14.8V rating limit which chargers or laptops I can use this battery with?

The 14.8V output matches the voltage requirement of the listed Inspiron models, so it works with the original charger and motherboard without any adapter or configuration changes.

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