12v - 12w solar pump, trickle batteries

[case-sensitive]

Hi good people,

my previous experiment with a solar pump did not go too far just yet, won't cope with murky water.
Now I bought this one
**broken link removed**
12V membrane pump, which draws about 1A no load on 12V on the lab supply. There will be not much pressure/head, in what I am going to pump, so maybe 1.5A worst case.
Its meant to be solar. It just pumps water, when there is too much in a pool. Most likely in rain season then. I guess there is not much point getting a 20W panel, since its not going to happen in Melbourne summer. Rather I would get maybe the battery pack of my accu drill and trickle charge it and every now and then it maybe has to pump 20L, thats done in 6 min, acc to the specs. Suppose even a half dead pack will do for short bursts, 2x 18V 1Ah packs gets 3Ah on 12V? I maybe just has to work once a week. So it could trickle away on like a 2W panel or less, 1/40 of the capacity?
I guess I could somewhat shade the panels in summer.

 

[alec_t]

2x 18V 1Ah packs gets 3Ah on 12V?

Only with a 100% efficient DC/DC converter . 18V will probably kill your pump.

 

[case-sensitive]

its NiCD.
I would pull them apart. Suppose its 1.2V cells, so 10 in series, 3 of them parallel. Gets 12V and 3 time the capacity.

 

[ronv]

Maybe buy a small lead acid 12 volt battery and charge it with the little panel.

 

[case-sensitive]

yes, 7Ah for AUD 19 or so and lifespan of 6 years, beats the dying NiCd....
The smallest PV panel I can get is 5 W
https://www.lowenergydevelopments.com.au/index.php?route=product/category&path=59
is that too much if it charges the battery all day? I reckon I could cover the panel in summer, in winter its mainly cloudy in Melbourne, may well need it
then all I need is a 12V relay and use this schematic
https://www.electro-tech-online.com/threads/solar-drain-pump.123536/

 

[NorthGuy]

7x12 = 84W. If it's half discharged, it'll need 42W - probably 2-3 days for 5W panel in good sunny weather.

It is vey easy to overcharge a lead-acid battery, so it's a good idea to get/build some charge controller.

 

[rumpfy]

The reference you gave shows a pump which is like a chinese copy of a FLO-JET pump type LR22202A.
These are commonly used as caravan water pumps. The pressure switch on the end cuts in at 35 psi. I use these on a single spray head unit attached to the ride-on mower for spraying Roundup along the vine rows in the vineyard. The Flojet is 12 volt and a 3.5 amp maximum current. In my application I run it from a variable voltage power supply so that the output pressure at the nozzle is around 25 psi and the pump runs continuously. It is fairly robust, although it runs with a water and 1% roundup mixture. At a voltage of around 6 volt, the pump needs about 2 amp when spraying.
In your case, the pump will run into an open pipe so the back pressure will be low and accordingly, the motor current will be small. Probably less than 1 amp. So all this stuff agrees with what your experience is.
My experience is also that running these kinds of motorised appliances on higher voltages doesnt do any harm. I have a GMC drill which has 18 volt 1.5 amp hour battery pack and again, this is your experience.
My approach would be then to just run the pump on the 18 battery and dont worry about it.
Actually we are in Bacchus Marsh and our problem is we have to keep filling the pool. I guess you are in the east somewhere, and your problem is you have to keep emptying the pool. If you have any spare water you pump it to our place!!!
I must say too that I dont like the look of the clear plastic moulding; looks to me like it would be sensitive to UV degradation so I'd be keeping it in the dark away from sunlight. There's not too many places where UV degradation is real problem like it is for us in OZ. The flojet is bullet proof from this point of view.

 

[case-sensitive]

am in Preston, north-east then. Its not a pool, what I want to do is drain water away from the house into a pond, then pump it into the stormwater inlet on the driveway, which is a bit higher.
Pressure switch, I think the pump kicked in when I put it into water.
Charge controller, could be lazy, get one at Jaycar for $29.
UV radiation, suppose I put it into some box to keep it out of the weather.