why are cordless tools rising in voltage?

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I’ve owned cordless tools of various kinds since I was a teenager and they were always marketed by voltage. In the nineties, 9.6 volt was the big thing. Then in the 00s it was twelve volt, and eventually 24. Now it seems like the larger tools are all 40 volt and above, but not all; my chainsaw is 24 volt and cuts down small trees just fine, and my string trimmer is 40 volt and doesn’t seem to be any more powerful than the chainsaw but the battery lasts longer.

What I don’t understand is why these things seem to be growing in voltage rather than amperage, and in marketing it seems like the voltage is supposed to be a proxy for how powerful it is. I understand the larger tool needs more power but why are the cells wired in serial rather than parallel?

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9 Answers

Anonymous 0 Comments

Power (Watts) is Current (Amperes) times Voltage (V).

So yes, you could get the same power raising the current instead of voltage.

But it’s just easier to raise the voltage. With higher current you need thicker wires and larger contact surfaces everywhere – including in the motor windings and charging equipment.

Power is usually controlled with PWM (pulse width modulation), and electronic components for higher currents are larger and more expensive than components for higher voltage (for the same output power).

TLDR: getting more power with higher voltage is cheaper and smaller than getting the same power with higher current.

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