~ jan wrote:

On Fri, 11 Jul 2008 16:21:05 EDT, DavidM
wrote:

I can't find much via google on serious 12 volt pond pumps. Are there
any r.p.m readers using one, or know of one that can pump suitable
volumes for use in a 5000+ litre pond?

I'm interested to know the power requirements and feasibility of running
from a car batter charged by photovoltaic panels. The price of solar
panels seems to be dropping all the time, and with energy costs going up
it might be worth looking into.

I'm hoping you'll find an answer here. I know my son is trying to figure
out how to power my motion sprinklers via solar. At least where the
batteries are charged during the day, and will run all night. ~ jan

First, don't use a car battery. Sure they're cheap, but they won't last
long.

But really, I don't think such a beast exists. I bought about the most
efficient pump I could get, for my 5000 _gallon_ pond, and it drew ~215W.
Let's just pretend you could use something a quarter the size for 5000
liters (probably you'd need bigger). 50W 24 hours per day is more power
than my entire solar powered home uses! That's 1.2KwH daily, and I use
about 1KwH for my house. I run 800W of solar panels to get that.
Admittedly, I need to account for short winter days, and foggy Springs, and
since you'll likely only need it in the summer, and may have much more
sunlight, you might conceivably get by with only about 400W.
--
derek