I think there a number of alternative energy solutions at reasonable prices
ShurFlo makes inexpensive($80) 12v pumps with built in pressure switches.
Not a lot of flow, about 2 gallons/minute. Google is your friend.

M Hamlin

"Cristian" wrote in message
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Supposing I should use a pump (another or the same), what solution
should I use to have water all the time I need? An electrical device
(could be also incorporated in the pump) should start and pumps the
water from the cistern. But this kind of pump is expensive also.