• Lithium batteries have great capacity, light weight, long lifetimes.
  • NiMH batteries are OK-ish, medium capacity, good voltage levels over discharge level, heavy weight, medium lifetimes
  • NiCd batteries suck. low capacity, normal weight, low lifetimes, bad for environment.

So I replaced my old battery packs with lithium-ion batteries from old laptop batteries.

Dead laptop batteries often have only one or two dead cells or have been left uncharged for too long.  So I measure each cell and if the battier is above 2V I keep it, lower I recycle it.  Mixing Li-Ion batteries is not the best solution but I had to use various old laptop batteries, and it works.  Possible problems with mixing batteries are if 2 different batteries with different capacities, the lower capacity could discharge below minimum level and cause damage, lowering the capacity even more.  Not the end of the world.

Drills I have modified

Skil 2585

  • Voltage Rating: 14.4V
  • Original batteries: DW9061
    • C-cell, NiCd
    • Capacity: 1.2Ah
    • Load: forgot to measure before I recycled them
    • Cost: $50
  • New homemade battery configuration
    • 8-cell Lithium-Ion 18650
    • Configuration: 4S-2P
      • 4 is series gets pretty close to the voltage rating
      • 2 in parallel  @ 2C, with new batteries, max recommended current would be 16A
    • Voltage: 14.8V (12-16.8V)
    • Capacity: 4Ah (2Ah with my used batteries)
    • Measured Load: forgot to measure
    • Protection circuit: 15A 4S Li-ion Charger Protection Board
      • Max average current: 15A(Natural cooling 10.A, add heat sink 15A, the maximum instantaneous current 30A)
    • Add-on: 4S Lithium Capacity meter indicator/display

 

Dewalt DW952

  • Voltage Rating: 9.6V
  • Original batteries: DW9061
    • 8-cel, C-cell, NiCd
    • Capacity: 1.7Ah(DW9061 XR)
    • Load: forgot to measure before I recycled them
    • Cost: $50
  •  New homemade battery configuration
    • 6-cell Lithium-Ion 18650
    • Configuration: 2S-3P
      • I was worried that 3 in series would make the voltage too high (9-12.6V)
      • I decided to put 3 in parallel to supply the high current @ 2C max recommended current would be 18A
    • Voltage: 7.4V (6-8.4V)
    • Capacity: 6Ah (3Ah with my used batteries)
    • Measured Load: 5A(no load), 20A(extreme load)
    • Protection circuit: 2 S 15A 7.4 V Li-ion  Battery Protection Board
      • Maximum continuous discharge current: 15A
      • Over current protection: 20.8A
    • Add-on: 4S Lithium Capacity meter indicator/display

 

Batteries used

LGABD11865

  • Nominal Voltage: 3.7V
  • Size: 18650 (Cylindrical)
  • Capacity: 3000 mAh
  • Chemistry: Lithium Ion (Rechargeable Li-Ion)
  • Brand: LG

 

LGABC11865

  • Nominal Voltage: 3.7V
  • Size: 18650 (Cylindrical)
  • Capacity: 2800 mAh
  • Chemistry: Lithium Ion (Rechargeable Li-Ion)
  • Brand: LG
  • Max Charging current: 2.7A
  • Max Discharging current: 5A

Sony US18650GR (G6 date code)

 

 

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