Cordless drill motor- power supply?

I thought a cordless drill motor with a two speed gearbox would be perfect for the beefy peristaltic pump I'm building. 300RPM on low, lots of torque, use the chuck to spin the roller wheel. Just use my 12V 10A power supply. Piece of cake....I thought.

I did some searching and it seems the problem is, if I understand it correctly, the wrong kind or not beefy enough power supply.

The motor is RS-550VC-8022. It's from a very lightly used Hitachi cordless drill. I was excited because I owned this exact tool years ago and worked it hard, wearing out three batteries and the drill was still going strong.

I need this motor to turn on full power for maybe 10-20 seconds four time a day. It will startup under a load.

If I have this right and need a different power supply, could I get a recommendation?

What is a motor voltage and power consumption?

You didn't exactly say what problem you're having. That would be a useful start.

Will the motor run on your 12V 10A supply if it is directly connected with no load connected to the motor? With the load does it run at all?

I've seen RS-550s running at 25-30A under load but they don't last long at that sort of power. They're basically 80W motors so you wouldn't expect the running current to be more than about 7-8A. Unfortunately startup current will normally be quite a bit higher.


When I connect the motor to my 12V, 10A power supply the motor barely spins then stops then barely spins, etc,.

It’s a 12V motor. I couldn’t find anything specifically on RS-550VC-8022, but found this. There seem to be a lot of versions of the RS-550 motor.
I’m surprised about the amps. Am I right to give up on this motor to drive my pump?

RS-550 Motor 19300rpm 12V 62.49oz-in

Nominal Voltage: 12V
No Load RPM: 19300
No Load Current: 1.4A
Rated RPM: 17100
Rated Torque: 7.86 oz-in
Stall Current: 85A
Stall Torque: 69 oz-in
Shaft Type: Round

The motor is RS-550VC-8022. It's from a very lightly used Hitachi cordless drill.

Do you have the LiPo battery pack for that drill? That's a supply that is known to work.

I don't have a Hitachi battery. I bought the tool only thinking I'd use the motor, gearbox and chuck. I did hook it up to a 12V car battery and it ran. I'm not sure if it was full speed but it did run steadily.

I did hook it up to a 12V car battery and it ran.

Use your multimeter (on the 20A range) to measure the current draw, free running and under load.

No load, I got 9A for a split second then 1.95A.

Under a load that I feel is greater than what the pump will exert, I got about 12A at startup and then 7A.

Do you guys agree that a 12V, 40A power supply should do the trick?

Thanks all.

Sounds likely.

One issue with power supplies is that most are not designed for powering motors.

A supply for a motor ought to current limit on overload, not cut-out, so the motor
has a chance of picking up speed from the stationary (stall current) state.

Thanks, I'm going to try a generic power supply and keep my fingers crossed. Thanks all, it's much appreciated!