Doug Winterburn wrote:
J. Clarke wrote:
Skip Williams wrote:
Kenneth,

I wonder if a solar or wind powered charger would be sufficient
for
the battery backup on the sump pump. 15-20 hours is quite good by
itself, then add to that changing from solar power during the
day...should be enough to keep the sump pump running intermittely
for
a long time.

If his pump is cycling every 30 seconds and draws say 2 amps then
that's a 110 watt load---if it's winter then triple that because
the
days are short and you've got 330 watts worth of collector
required,
plus losses due to various inefficiencies. Not considering air
mass
and average cloud cover at his location and suchlike, I'm pulling
500
watts out of my butt as a number. At the 8 bucks a watt that I'm
seeing in various places, that's $4000 worth of collector alone,
then
you have to add inverter, batteries, etc.


If the sump pump is running almost continuously (cycling every 30
seconds), it's beginning to sound like his money might be better
spent
on a backhoe, gravel and drain pipe...

He said that he had seen times when that happened, and also times when
he had had an outage for 96 hours--that makes for an engineering
spec--has to run the pump at 50% duty cycle for 96 hours plus whatever
margin one wants.

--
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)