PV powered rainwater pumping

[wormscoffer]

Hello all

I'm sure the answer to my question is already in the forum threads but I've searched for some time and can't see to find a clear answer so please excuse me asking directly.

What I would like to do is fairly simple. I have a large water butt collecting from the roof. I'm going to put another water butt at the top of the garden where I can use gravity to water the garden as and when needed. The garden butt will be about 30 Metres away from the house butt and 5 Meters higher.

I would like a PV powered pump to move the water, maybe slowly, when sunshine allows. I though I could use some of these to stop the pump when one tank is empty or the other is full.

http://www.virtualvillage.co.uk/horizontal-liquid-tank-float-switch-009700-019.html

Thanks in advance for any suggestions.

Andrew

[martin W]

the simple answer is yes, you could use a solar pump to move the water from one butt to the other.

I would use two float switches.....

1. fit one switch at the full level of the top water butt so that if the but is not brim full of water then it says turn on pump.
2. second switch fitted at low level on lower butt (but above pump unlet). this float switch will turn off the pump if the water level is low and stop you burning out the pump.

The problem i see is specing a solar pump that will pump up the 5m rise required off a small solar panel and with a flow rate that is suitable for your needs. And of coarse it being cheap and reliable.

I think there are some cheap 12v pump about, but I don't know what head the can pump up...

[Stefan (S.T.E.F.)]

How about a 12v caravan pump ?

[clockmanFR]

I have been using this design for the last 4 years. Problem is the pump or pumps, raise it 5m and you need a good 8 amp 12v job. Our design is 3 shurflo boat bilge pumps each drawing 1.8amps at 12v and putting the water up to 6 meters. solar Panel (170W) charges 2 small Sealed lead acid constantly. No1 pump sits in the source has a float valve so it shuts off if runs out of water, (Pumps do not like running empty) pumps to small plastic house type  header tank at 2m high. inside is No2 with float system, this pumps to another header tank with No3 in it also with float switch. Both header tanks have overflow pipes that feed back to source along side the pumping hose. I used 25mm dia underground water pipe, (keep corners smooth no right angle joints) and cheap plastic waste pipe as overflow. When water required switch on pumps and the big tank fills and overflows back so no wasted water.

Some times when it is nice and sunny the solar panels will run the pumps direct, and its very musical as each pump comes on and off and the power changes accordingly. The main tank under gravity supplies water 150 meters to the garden. (35mm plastic)

In winter i just pump out and drain main tank, but these modern plastics and plastic pies stand the frosts and the - 20 C.

The total costs for this came to approx £600, includes 1500 litre tank which takes about an hour to fill, PV etc.     

[w0067814]

I was looking for low power pumps with the view of running one from a small solar panel of just a few watts (around 10 - 15 ish) with the view of lifting a trick of water from my well (<2 meters deep) to my IBC (2.2 meters at highest point) to keep it topped up and negate the need to trudge down to the allotment with a generator every few weeks.

I came across these:

http://www.williamson-shop.co.uk/200-series-with-dc-powered-motors-4371-p.asp

From the datasheet, this pump can move up to 389ml/minute (23 litres per hour) and requires only 400mA @ 12v. Not bought one yet, but I think that they are worth a look for low volume applications. My idea is simply to replenish the @200 litres a day maximum that the allotment can require during a drought (big plot!) using just a solar panel. The nice thing about these pumps is that they do not require foot valves etc and if they stop pumping the water in the pipe will not run back to the bottom and be wasted.

http://www.wmcpumps.com/pdf/200_dc_motor_spec.pdf

-Tim

[clockmanFR]

I did think of this type of Medical pump, Tim, but concluded that it might not cope with the exterior climate conditions and contamination in the water, ie, the odd water snail etc.

Here's a pic of the permanent installation. Storage pond approx 100,000 litres, 3 stage reed bed 20/2m system for all grey water and rain water from the house buildings etc. In the building on the pic, we have an underground spring coming up, but in the hot summer months this stops and then we pump from the main storage pond. Plastic water tank in the tower is 1500 litres.  Half way up the tower is number 3 pump installation and small tank. 

[clockmanFR]

Here is pic 2. The reed beds. No the storage pond is not that big, but we inherited a sea boat so modified the pond to suit. The 3 boy's have great fun, also used the boat to take my step ladder so i could re-tile the roof.