georgeesarn

You even say your measured output current is only 4.2 amps from the one panel???? I think if you want to save money on this, pull up your pump and see what happens then you know for sure. What are you using to measure the current with?

I think you will find that whats happening is you don,t have enough current to get the pump going and you are loading down the voltage and current, kind of like a short, remember your motor is an inductive circuit.You could confirm the solution if you had an external power supply that could put out enough current. Of course you could have a bad pump.. if you could pull it out and see if would run with no water, I think if it didn,t run you could say that it is defective or clogged.

doing a bit of rule of thumb calculation I use a 20 - 25 % real rating of the panel as around 70 Watts so at full sun light at 24 volts you will get around 3 amp (70 watts) output, not enough to run this pump (8 amps). assuming all connections and such are good I would say you need at least another panel which would bring you up to 6 - 7 amps (144 W - 168 W) My personal pool pump I use 3 450 W panels with controller and runs reliably except for rainy days..

how about show us a picture of the label on the pump and the label of the controller and we can see if they are correct??

For starters, you say that your panel is on a boat, what direction is the panel pointing at??

Got a big c up here I find reservado and flamingo cab sav pretty good and low cost at 500 and 400 respectively.