Ever wondered why there aren't more electric power washers?

  • 04/11/2021 5:43 PM
    Message # 10300415

    My 20+ year old electric pressure washer gave up the ghost this afternoon, so I was looking for options to rent, or replace.

    The problem is, anything that is powerful is fitted with a gasoline engine.  I searched for an electric one, but the issue is that with standard 110VAC connections - a 2,000PSI pressure washer draws 13A, which is max for a standard circuit.

    A 4,000PSI pressure washer that I looked at had a 15Hp engine, equivalent to 10KW.  Granted an electric pump would probably be de-rated to 8KW because of efficiencies, but even still that would require the equivalent of a 50A Stove connection at 220VAC.  That type of power is not conveniently installed in most homes, and the extension cords at that voltage and in wet spray conditions are probably not a good mix for safety and shock avoidance.

    Looks like we need to go to battery powered systems, and they'll probably need about 20kWh of batteries on board for, say a 2 hour run time.  This is problematic for commercial pressure washers because their run time is likely 4-7 hours per shift.

    Looks like we still have a ways to go in electrifying these types of machines.

    3 files
  • 04/28/2021 11:19 AM
    Reply # 10389447 on 10300415
    Gordon Wong (Administrator)

    A 160 cc Honda engine is 3.5 kW (4.5 HP) so 2 hours of running is 7 kWh.  The most energy dense chemistry is lithium cobalt (NCA).  That would be 15 litres of 18650s or 10 litres of 2170 cells.  So you have to figure out how to add 3 or 4 milk jugs worth of batteries to your wheeled power power washer.  Replacing the engine, carb and gas tank with a fan cooled 3 HP treadmill motor reduces the space by a milk jug right there!  I'm sure some scrounge in the US has converted one in their workshop for $500 to meet some challenge. 

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