I'd like to submerse a pump for a water feature (fountain) and power it off a solar charge meant for small electronics (iPhones, such).

The pump asks for 3.6amps... The charger creates 600mA...

Here's the thing. I don't need to use the 1/5 horsepower pump to full potential... I don't want to shoot water 5 feet above the fountain!

So, will the limited power force the pump to work slower, less optimally, or will it fail to reach an "activation?"

Thanks!

Do some calculations and decide the rating(Ah,Volt etc) of the battery required to power the pump and charge it by the PV array. Depending on the rating of the array you can calculate the runnning time of the pump without allowing it to discharge more than 50% of the charge.