Solar hot water pumps, - PV array sizing & BLDC pump
Posted: Mon Jun 23, 2008 12:29 pm
A colleague at work has put a PV powered electric pump on his roof mounted solar heating array. From ebay he got an array of parts including a small BLDC pump and a £50 PV array (12W).
It didn't work - the array voltage just collapsed with the pump wired in. He was going to buy a bigger PV array, but I suggested that the problem might be tha pulsed current taken by the pump & that a capacitor might solve the problem. To my great surprise, I was right! A 2200uF capacitor across the output & it pumps like billyo - saving him a further £50 bill for more solar cells.
It didn't work - the array voltage just collapsed with the pump wired in. He was going to buy a bigger PV array, but I suggested that the problem might be tha pulsed current taken by the pump & that a capacitor might solve the problem. To my great surprise, I was right! A 2200uF capacitor across the output & it pumps like billyo - saving him a further £50 bill for more solar cells.