They differ in 3 of 4 areas
Same tools, so this is about size, weight and cost. No overall winner: pick the size that suits the job.
EnergyThe 4.0Ah stores 100% more than the 2.0Ah: 72Wh vs 36Wh.
WeightThe 2.0Ah is the lightest at 0.38kg, the 4.0Ah the heaviest at 0.56kg.
Size2.0Ah 116 × 76 × 49mm; 3.0Ah 116 × 76 × 49mm; 4.0Ah 134 × 83 × 54mm (L × W × H).
Good to know
Same toolsAll three fit every HiKOKI 18V tool.
Same chargersUC36YSL2, UC18YFSL and UC18YKSL charge all three. Charge times are in the specs below.
Energy
BSL1820M
36Wh
BSL1830C
54Wh
BSL1840M
72Wh
Maker figure, or volts × Ah where they don't publish one. Ah and Wh explained ›
Weight
BSL1820M
0.38kg
BSL1830C
0.38kg
BSL1840M
0.56kg
Full specs
BSL1820MBSL1830CBSL1840M
Voltage18V18V18V
Capacity2.0Ah3.0Ah4.0Ah
Energy36Wh54Wh72Wh
Weight0.38kg0.38kg0.56kg
Energy for its weight95Wh/kg (worked out)142Wh/kg (worked out)129Wh/kg (worked out)
ChemistryLi-ion (cylindrical)Li-ion (cylindrical)Li-ion (cylindrical)
Cell typeNot listedNot listed21700 cylindrical
Fuel gaugeYesNot listedYes
Size (L × W × H)116 × 76 × 49 mm116 × 76 × 49 mm134 × 83 × 54 mm
Charge time, UC36YSL220 min30 min40 min
Charge time, UC18YFSL30 min45 min1 hr
Charge time, UC18YKSL1 hr1 hr 30 min2 hr
Lowest priceNo retailer price yetNo retailer price yetNo retailer price yet
Specs from each maker's own documentation. "Not listed" means the maker doesn't publish it or we haven't found it yet; it never counts as a difference.
Battery guides
Not sure what the numbers mean, or which platform to buy into? Start here.
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