solar power controller

If the photovoltaic panels [PVs] are connected in parallel with a bank of lead-acid batteries so as to charge them, and then feed the inverter from the batteries, then apart from a meaty rectifier to prevent the PVs being damaged during cloudy periods further equipment is probably unneccessary.

48V x 40A might indicate a photovoltaic array in excess of 40m² in area. Wow! <Much drooling, dribbling and envy> The other possibility is to reconfigure the array so as to produce something closer to the 48V required, rather than the 72V.

If the appliances in question have a DC power input then it might be possible to take the power from a small number of batteries in the bank at an appropriate DC voltage (similar to a 'tapping' on a transformer), so as to eliminate the inverter losses, thereby gaining further efficiency improvements and making the most from a dilute energy source.

Thanks for the comment, Crabtree. I saw solar water pumping installation here in the Philippines that uses Grundfos pumps and inverter. It does not need bank of batteries. It only pumps water during daytime, when there is sunshine. It has an array of 7 X 18V PV Module in series and 5 X 3amps/panel in parallel. So the total power output of the array will be 1,890Wpeak at peak sun-hours. The output of the inverter is 60Vac at 4.7amp max., 3 phase to power the pump motor.

Since the pump is already defective, it has reach its service life. No budget for replacement from the agency that put it up. Perhaps they plan to convert it to grid, since its within reach already and replace the pump which run on utility power. I plan to make use on the potential of the pv module to generate electric energy which is being left unused and disregarded.

Your right, i have to reconfigure the array. Before, I am already thinking of making a series of 3 panel that would equal to 54V. But i think the difference of 6V, may be too small voltage that the converter/controller may lost its regulation for 48V. That is why I said 72V.

Upon research, i found out that most available inverter will accept an input of +/- 20% tolerance, which in the 48V inverter system, 54V is within its limit. So, I dont need for a converter/ controller anymore. I can tap the inverter directly to the array. Anyway it still need experiments just to make sure.

thanks again for you time and comment.