Originally Posted by fons
take the biggest (7ah)then you can use the pump for about 3,5 hours .
7ah:2.1amps is about 3,5 hours
Exactly.
How long you want to run the pump is the key!!
You can also buy bigger batteries than that and for cheaper money I got some 7ah batteries for about £14 each for example. That was from
www.cpc.co.uk