Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Help powering 12v bilge pump with 65W power bank and Power Delivery trigger (ZY12PDN)

Camtron

New Member
Hi folks,
I am attempting to power a small 12V 3A bilge pump (I'm not using it on a boat) with a power bank that supports Power Delivery up to 65W and is rated to do 12V 3A.
I have a 100W USB-C to USB-C cable connected to the PD output port of the power bank and then to a PD trigger (ZY12PDN) with the trigger locked to transmit 12V power. However whenever I attach the pump's two cables to the + and - screw terminals on the PD trigger, the light on the trigger immediately goes out (shuts off). I feel like the trigger is shutting down to protect itself. Would that be because attaching the pump is causing some sort of surge? Do I need some sort of controller to start with low power and crank it up slowly?

I have seen a few YouTube videos of people using PD capable power banks with ZY12PDN triggers to power various 12V DC devices (though not a pump) and they don't seem to have an issue like me.

Any help or suggestions would be much appreciated, I am new to electronics.
 

Diver300

Well-Known Member
Most Helpful Member
DC motors take a lot of current when starting. If it's a simple permanent magnet DC motor I would expect it to take around 5 times as much current for about 100 ms. That will be far too much for the power bank and the motor will effectively be a short circuit.

I suggest that you try to measure the starting current.

You might be able to limit the current during starting using linear regulator or PWM.
 

Pommie

Well-Known Member
Most Helpful Member
Your numbers don't add up, 12V @ 3A is 48W not 65W. As Diver says it's probably the start current, can you measure the resistance of the motor as that'll give the start current.

Mike.
 

Camtron

New Member
DC motors take a lot of current when starting. If it's a simple permanent magnet DC motor I would expect it to take around 5 times as much current for about 100 ms. That will be far too much for the power bank and the motor will effectively be a short circuit.

I suggest that you try to measure the starting current.

You might be able to limit the current during starting using linear regulator or PWM.
Thanks @Diver3000. Would you reckon one of these would do the trick?
 

Camtron

New Member
Your numbers don't add up, 12V @ 3A is 48W not 65W. As Diver says it's probably the start current, can you measure the resistance of the motor as that'll give the start current.

Mike.
Hi Mike,
65W is just the max output that my power bank Type-C PD port is rated for. At 12V it can only output 3A (it can do 20V 3.25A which is how it rates as 65W).
I guess if I am going to be tinkering with electronics I will need to get myself a multimeter... Thanks, Mike!
-Cameron
 

Diver300

Well-Known Member
Most Helpful Member
Thanks @Diver3000. Would you reckon one of these would do the trick?
That would reduce the current, but what you probably need is something to allow it to speed up gradually. The device you linked to has just a knob to control the speed, and if you are wanting it to turn on an off, you either need a power supply that is powerful enough to let it start, or something that limits the current when the motor is turning slowly and then increases speed.
 

Camtron

New Member
That would reduce the current, but what you probably need is something to allow it to speed up gradually. The device you linked to has just a knob to control the speed, and if you are wanting it to turn on an off, you either need a power supply that is powerful enough to let it start, or something that limits the current when the motor is turning slowly and then increases speed.
Would this be more appropriate?
 

Diver300

Well-Known Member
Most Helpful Member
Would this be more appropriate?
Are you wanting to have the pump turn on and off automatically.

If not, either controller could be fine. Just turn on with the control knob set to the minimum, and turn it slowly up to the maximum. That should allow the pump to start with just about no turn-on surge, but very gradual starting.

If you do need something that will turn on and off automatically, you would need a more sophisticated controller that could let the motor speed ramp up slowly.
 

Camtron

New Member
Are you wanting to have the pump turn on and off automatically.

If not, either controller could be fine. Just turn on with the control knob set to the minimum, and turn it slowly up to the maximum. That should allow the pump to start with just about no turn-on surge, but very gradual starting.

If you do need something that will turn on and off automatically, you would need a more sophisticated controller that could let the motor speed ramp up slowly.
I will be turning on/off manually, so setting to the minimum before turning on is easy to do.
I'll give it a whirl with one of those controllers and see how it goes!

Thanks again for you help! Will report back once I have a chance to test the new set up.

Cheers,
Cam
 

Camtron

New Member
Thanks to quick shipping from Amazon, I was able to test out the PWM controller today. Worked like a charm!

Power bank PD port to PD Trigger set at 12V to PWM motor speed controller (6-24V, 3A) to my bilge pump. Picture attached. The extra on/off switch is handy and can crank the pump from 0 to 100.

Thanks again for your assistance!
 

Attachments

  • 20220302_203233.jpg
    20220302_203233.jpg
    4.2 MB · Views: 106

Pommie

Well-Known Member
Most Helpful Member
Thanks for taking the time to let us know the outcome.
And, congratulations.

Mike.
 

Latest threads

New Articles From Microcontroller Tips

Top