I recently bought the following for a grey water system project I'm working on:
I'm not an electronics expert, so my assumption was that the power supply should easily power the bilge pumps. This was not the case. The moment you connect the pump to the power supply, it's like it sucks the power supply dry (the LED actually dies). The bilge makes half a spin every 1.5 seconds or so, the LED goes back on and the process repeats. So I thought there is something wrong with the power supply.
Because I live in South Africa, shipping the part back to Amazon was a bit of a mission, so I decided to buy another power supply locally as I thought the original was faulty. This one was 100 W, 8.5 A supply.
It works a little better; the pump actually spins up after the third 1.5-second burst. If it is submerged however, it's again as if the power supply cannot supply enough power to the pump. As long as I get it spinning before I submerge it, it works fine. It's almost like the supply needs some help getting out of the starting blocks.
It's obvious there is a critical piece of knowledge I don't have here. Can someone please explain why a power supply rated for 12.5 A or 8.5 A (12 V) cannot power a 12 V, 3 A bilge pump?
I run it off normal 220 V AC, 50 Hz.