Instructables

coverting 24volt rechargeable lawn mower to use direct AC wired connection.

I am not able to start a gas mower and so I utilize a very old electric mower. A friend gave me a black n decker rechargeable 24 volt lawn mower, no "key" and no charger.  I was pondering putting an AC/DC power converter on the mower body and then using an extension cord to power mower. But concerned about running motor direct from converter. I would of course by pass the battery pack and go direct to motor because there are always warnings about not running an appliance while charging. So thinking along these line took cover off motor body and off the wiring in the handle.  Upon inspection except for the wires going to the batteries from the motor, the motor itself looks like the electric motor in my old direct electric lawn mower! My question is: Would it be possible to directly wire AC power to the motor of this DC powered motor? I am not an electrician but understand some basic principles. After reviewing specs on B & D's webs site know that there is some type of inverter built into the battery pack. I'm assuming it is to convert AC to DC for charging them. Could I wire directly to it then to motor and not use the batteries? I survive on a very low fixed income and can not afford to buy a replacement charger and needed "key" (connects wires to make it run). I do have wire and soldier and a desire to make it work. Any advise would truly be welcomed.  Otherwise I will proceed with my inkling of an idea and tell you how it goes or not! thank you.

A high current step down transformer and rectifier.
Simple in theory the output of the transformer and the current carrying capacity of the rectifier need to match the motor.
You would need to change things in the mower. Using the AC to DC converter in the mower will not work. That converter doesn't put out a lot of amperage since the battery doesn't need a lot when charging.

What you need to do is figure out the specs of the motor. How much voltage does it need and how many amps does it pull. Then you can build the circuit to take your 120VAC and convert it to the voltage and current that the motor needs with some room to spare. Essentially you'll have to design and build a power supply for the mower. This can be a very difficult and daunting task for even those experienced in electronics.