I'm trying to power a cheap submersible pump for a bird bath 5v 1a. Got a portable phone charger/power bank 5000mAh 5v 2.1a. But the motor only runs for about 10 secs. Do I need a more powerful power bank? (Volts/amps not mAh) Thanks

 

More likely your powerbank doesn't like powering motors... If its 5000mAh it should run that motor for 5 hours (assuming its charged). But motors are finiky things, they take a lot of current to start and are electrically noisy, both of whch could upset the protection circuitry in the powerbank.

How long do you want the pump to run for?

 

More likely your powerbank doesn't like powering motors... If its 5000mAh it should run that motor for 5 hours (assuming its charged). But motors are finiky things, they take a lot of current to start and are electrically noisy, both of whch could upset the protection circuitry in the powerbank.

How long do you want the pump to run for?

It's for a bird bath. I want it to run all day. I didn't want to have to plug it in to a wall outlet. Spent more than planned but I got a 12w power bank and it seems to be working. So far.

 

12W? So 12/5 = 2.4A, but how many Ah? The two I found are either 5000mAh or 10000mAh. So they have only slightly more output capability which suggests your original (cheap?) powerbank's supposed 2.1A output capability was probably just marketing guff (typical chinese product). 5000mAh will run it for 5h, 10000mAh for 10h, assuming a) fully charged to start, b) the mAh is true (most are out by up to 50% - I've tested a few and only well known branded ones come close - the Belkin 10000mAh I have is 9800mAh, all the cheap chinese ones are < 50% of stated capacity) and c) your pump actually needs 1A to run (its probably less).

Ideally you'd measure the actual running current of the pump, when pumping water, as that will tell you just how much battery capacity you actually need - and then you could, maybe, also look at a solar powered solution?

 

Thanks for the info. I had guessed that my original power bank was cheap (Insignia) and not delivering as much power as promised (tho the motor is cheap too). To troubleshoot I had plugged the motor into computer USB and it worked fine. So I got a 10000mAh (Anker) that states 12W with USB-A and 18W with USB-C. Gave it a full charge and it ran all day. Tried solar (also cheap) and it only did well in direct sun. With the not-cheap Anker it's so far so good.

 

Solar with battery backup (for when its not so sunny) and a light sensor so it doesn't run at night... you can get them to operate garden water features...

 

I'll try that if what I have fails. Probably wouldn't be much cheaper, and most of the birds will be gone soon. Thanks for the help.