How lucky can I get! I was in to Canadian Tire (CDN automotive/hardware chain) and they had a 12 volt backup kit on sale (not advertised- reg $249.95 for $150)! Old stock I think. Says it pumps up to 1200 gph. I bought it and a deep cycle battery. Have it on the charger now. I'll put it in next weekend.
I only have to pump about 3 ft up to reach a drain. I'm thinking that should near maximize its pumping volume capacity.
Thanks for your help.
Keith