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Build Battery Packs

Cells

  • DIY500AMP.COM
  • Order #1584 2025-09-25
  • Ampace JP40 "LT Wrap" 21700 4000mah 70A Battery - Tabless Cell × 120
  • Subtotal $474.00 Shipping $22.99 Total $496.99 USD

Welder

  • Heltec HT-SW02H
  • Manual
  • Order #114-4340207-9060214 2025-10-30
  • Spot Welder & Milliohm Meter
  • 42 KW 7000A Capacitor Energy Storage Pulse Welding Machine
  • Subtotal $729.90 Tax: $43.79 Total: $773.69

Battery Case

Cost

  • Me: $497+$774+$390=$1660
  • Milwaukee (with worse cells): $279*8=$2232

Extra

    Balancer: 2A Active Balancer 2S–24S with Built-in Bluetooth RS485 and Temp Sensor for LiFePO4 Li-ion LTO 20V–100V Smart Equalizer Module (JK-DZ11-B2A24S)
      COM protocol HD26 connectors:
        male CN-DSUBHD26PN-000 female CN-DSUBHD26SK-000

        Assembly

        • video
        • cell orientation 20260903_10h57m14s_grim.png
        • bottom contacts 20260903_10h58m24s_grim.png
        • top contacts 20260903_10h59m38s_grim.png
        • side board 20260903_11h00m21s_grim.png
        • soldering 4 contacts to the board 20260903_11h00m55s_grim.png
        • obliterating this bit contact for some reason 20260903_11h02m14s_grim.png
        • case with pastic bits and springs 20260903_11h04m02s_grim.png
        • second plastic thing goes into the springs, then 4 tiny screws 20260903_11h04m30s_grim.png