I have seen on these posts frequent and satisfied reference to the topsider, which sells for about $40 & is a manual pump unit. I have found a Seachoice portable oil changer (pt # 50-19171), sold by marine supply shops & on the internet, which operates off the 12volt car battery via two alligator clips plus a has second tube to pump the old oil into a disposal container as the first tube sucks it out of the engine. It sells for about $27 & has a one yr warranty. Has anyone used or heard of the Seachoice? Thanks.