OEM and ODM rechargeable battery manufacturer in Shenzhen since 2008 [email protected]
Sunder Battery logoRechargeable cells and battery packs Request A Quote

Production And Quality

What we can show and state. Photographs are from our own plant and the testing item list is our own.

A note on claims. This page carries only what Sunder publishes about itself: the founding year, the workforce, the testing items and photographs of our own line. Certification numbers, monthly capacity and export country counts are deliberately absent until the client confirms them in writing. They will be added to this page at that point.
Manufacturing

How A Pack Is Built

The same route runs for a 3.2V cell pack and a 51.2V cabinet. Only the scale changes.

  1. Requirement Analysis

    Voltage, run time, peak current, ambient range, enclosure and connector. If the run time is still open we work back from the load and the hours you need.

  2. Chemistry And Cell Selection

    LiFePO4 where cycle life leads, lithium ion where energy density leads, lithium polymer where the space is a thin rectangle, Ni-MH where the product is locked to a 1.2V cell size.

  3. Series And Parallel Design

    The arrangement sets voltage and capacity. We publish it for every standard pack, for example IFR32700 4S17P for 12V 100Ah, so the comparison is transparent.

  4. Protection And Balancing

    Over-charge, over-discharge, over-current and over-temperature protection with internal cell balancing. Communication ports where the system needs them.

  5. Sample And Test

    After price confirmation you can request samples to test. Cells and packs are checked against the parameter table published for that model.

  6. Case Wiring And Label

    ABS or lead acid style case, aluminium case for e-bike packs, PVC wrap for modules, with your terminal, cable length, connector and logo.

  7. Production And Packing

    Built by our 500 worker factory, packed to the carton count agreed for your channel.

Quality Control

What Gets Checked

Our battery testing item list separates safety items from reliability items. Both are run against the parameter table published for the model.

  • Capacity against the typical and minimum figures in the model's parameter table
  • Nominal voltage and internal resistance where the data sheet publishes it
  • Charge and discharge current against the standard and maximum figures
  • Protection board function for over-charge, over-discharge, over-current and over-temperature
  • Cell balancing across a completed series string
  • Case, terminal, cable and connector against the customer drawing
  • Label, logo and packing against the agreed carton count

Cells in one series string are supplied from the same batch, which is what keeps a string balanced over its life.

12V 150Ah LiFePO4 battery packs before final packing
Plant And Packing

Photographs From Our Own Line

Every photograph on this page is from the Sunder factory, office or packing bench.

Sunder battery production line with workers assembling rechargeable battery packs
Production line. Our factory employs 500 workers to manufacture rechargeable batteries.
Sunder office where the R&D, engineering and management team works
Office. Our R&D, engineering and management team has more than 10 years of experience in this industry.
Battery testing item list covering safety items and reliability items
Battery testing items. The safety and reliability checks we run on cells and packs.
Finished battery packs boxed in cartons ready for shipment
Packing. Packs are boxed to the inner box and carton count agreed for your channel.
Battery pack inner packaging before cartoning
Inner packaging. One piece per inner box on service and retail parts.
12.8V 90Ah LiFePO4 battery pack built from cylindrical cells
Finished pack. A 12.8V 90Ah LiFePO4 assembly before its case goes on.

Ask For A Sample

After price confirmation you can request samples to test against the published parameter table.

Request A Quote Talk To An Engineer Request A Sample