Swimming pools blog

For the vast majority of people using electricity from solar panels
to run pumps is impractical. Some of the problems you would have to
overcome are:
Amount of energy needed. Typical pumps are 1/2 to 1 HP, which is 400
to 800 watts (output, inputs are 50% higher). This would require many
square metres of solar collectors, even in near tropical areas.
Power type. Most pumps are AC. Solar collectors produce DC. A sine
wave inverter would be necessary, (these are available, but there
would be conversion losses and the unit would have to be able to cope
with startup surges) or, alternatively, perhaps more likely, a DC
motor would have to be used.
Instability. Output from the panels would vary continuously. A large
storage capacity (batteries) would be necessary. When battery and
solar supply are low/exhausted the motor would have to be isolated to
protect the batteries from deep discharge and the panels from seeing

a “short circuit”. Motors require a much larger current when starting
up so the motor would need to be kept isolated whenever the batteries
were unable to provide this, and a worthwhile run time.
Overall, a solar system capable of consistantly providing 500 to 1000
watts of power would be a substantial and expensive project requiring
some electrical and engineering experience.
That’s not to say it couldn’t be done, though (although I suspect a
wind turbine or a combination of both might be more practical in many
areas). If anyone has such a system, please let us know!