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Rectangular lithium-polymer battery pack with connector and installation tools

MPF Products

MPF Products LSSP321830AE 120mAh 3.7V .40Wh Battery for Fitbit Blaze FB502

SKU CH-NQ16-HX0V8

Replacement lithium-polymer battery restores power to Fitbit Blaze models with 3.7V, 120mAh capacity

  • Battery typeLi-polymer Battery
  • Product typeReplacement Battery
  • Key featuresIncludes Free Installation Tools (Soldering Iron Not Include
  • 120mAh capacity restores original runtime for Fitbit Blaze FB502
  • 7V lithium-polymer chemistry matches factory power specifications
  • .40Wh energy rating ensures correct charge-cycle performance
  • Direct replacement for part number LSSP321830AE guarantees fit
  • Free installation tools included for immediate DIY battery swap

Replacement Battery for Fitbit Blaze FB502

The MPF Products LSSP321830AE is a 120mAh lithium-polymer pack built to restore power to Fitbit Blaze models including FB502, FB502GPKL, FB502SBKL, FB502SBUL, FB502SBUS, FB502SPML and FB502SPMS. It suits owners whose original cell no longer holds a charge and who are comfortable opening the watch case. Buyers needing a higher-capacity cell or a different voltage should look elsewhere.

Sustained daily cycling

Rated at 3.7V and .40Wh, the cell delivers steady output through repeated charge and discharge cycles typical of fitness-tracking use. Internal chemistry maintains voltage stability during continuous heart-rate monitoring, GPS logging and notification alerts without the sharp drops seen in aged original packs. The bundled installation tools simplify the swap, though a soldering iron is required for the final connection.

Exact part-number match

Compatibility hinges on the LSSP321830AE part number printed on the original battery; only watches listing that exact code are supported. Verifying the code before purchase avoids fitment issues caused by visually similar but electrically different cells. No other specification overrides this single identifier.

How it compares

Measured against everything we stock in Smartwatches & Wearables, at today’s prices. Recalculated every night.

Price $4.99
Cheaper than about 99% of the 2,527 comparable items (median $44.99).

Specifications

Product
Brand nameMPF Products
Product lineFitbit
Model nameCompatible with the Following Models: Fitbit Blaze, FB502, FB502GPKL, FB502SBKL, FB502SBUL, FB502SBUS, FB502SPML, FB502SPMS.
Part numberLSSP321830AE
Product typeReplacement Battery
Power
Battery typeLi-polymer Battery

Questions about this item

How much heat does the 3.7V 120mAh Li-polymer pack generate during all-day use?

The cell is rated at .40Wh, so normal Fitbit Blaze operation produces only gentle warmth — no active cooling is needed.

Which tools must I already have to install the LSSP321830AE replacement?

The kit includes plastic pry tools and tweezers; you must supply your own soldering iron for the board connections.

Will this .40Wh pack fit my original FB502GPKL without case modification?

Yes — it matches the LSSP321830AE form factor used in every listed Blaze variant including FB502GPKL, FB502SBKL and FB502SPMS.

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