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Or option D -- play a recording of a fountain plashing. :)
Rob P liked this
Right, thanks all for the help so far.

I am rapidly coming round to the conclusion that this battery: ... -728-p.asp

with my car/aircraft mains battery charger is almost certainly the right way to go. Cut off the existing connector to the pump, solder on a couple of crocodile clips and when not in use store the battery in the workshop and recharge it there.

So the question now is. roughly how long would a fully charged 4Ah battery run the pump for?

I am sure there is a way to do this, but I am uncertain as I haven't a clue where the "3.5 watts max" comes into the equation or what amps would be involved.

Rob P
nallen wrote:Or option D -- play a recording of a fountain plashing. :)

Good plan. Can I run this from the existing solar panel, or is there a wind turbine alternative?

The main issue is that I can't see the kitten being convinced it is a great idea. She has a smattering of Bengal in her DNA and shares the fascination of that breed with water.

ImageBearcat meets the water feature by Rob, on Flickr
Rob P wrote:Thanks John, so the one I linked at 6V will be good for 6 hours?

Rob P

Sorry didn’t spot it was 6 volt, but yes. Are you sure your charger will do 6 volt? Most do 12 or 24.
That's a good point. :shock:

My thought was that with no form of control / throttle on the motor, applying 12v would make it run at (approx) twice the speed it runs at now on 6v. We like the gentle cascade, we don't want a geyser. Or is this simplistic thinking?

skydriller wrote:Dumb Question: If its been bought online and not what you wanted, can you not just send it back??

That was the original Plan A until such time as we discovered that what we actually wanted wasn't readily available, at which point Plan A became "Ask the people on FLYER"

Rob P
Bill McCarthy wrote:The battery you linked is 4ah. If the pump draws 1amp it will run for approx 4 hours. 2amps and it will be 2 hours. Find out what the pump draws and do the maths.

But for longevity you don't really want to run it down much past 50%.

The solar cell is rated at 1.5W so at 6V that would be 0.25A that the solar panel can supply. This may limit the pump speed, and you may find that supplying 6V from a battery has a higher current draw and runs faster. Who knows until you try it? :-) (unless you have a regulated power supply where you can adjust the current supplied)

Rob P wrote:My thought was that with no form of control / throttle on the motor, applying 12v would make it run at (approx) twice the speed it runs at now on 6v. We like the gentle cascade, we don't want a geyser. Or is this simplistic thinking?

This is possible, for a short period of time before the motor starts smoking and burns out.

The easiest way of charging the battery is, as I said, to use the solar panel.

Would suggest putting a Schottky diode between the panel and the battery to stop the battery back-feeding the solar panel.

This even says, "These diodes are also perfect for standard DIY solar panel protection. (To block DC current from re-entering your solar panels and damaging the solar blocking or bypass diodes)."

If you buy 10 of them, you can keep a couple and give the rest away. Maybe to me. :D

Have a look at the Pro Elec range of batteries in CPC. I don't know if they're any good but they're quite cheap.

On the plus side, if you order from CPC, you can also get the diode from them.
Last edited by Paul_Sengupta on Tue Apr 28, 2020 3:09 am, edited 2 times in total.
I shifted sheep over to my other place today. There is no mains supply to provide them with drinking water, but there is a crystal clear well. I fill the trough with a small 12V submersible bilge pump (at something like £14) connected to the HI-LUX battery. The blurb states that it pumps 500 gallons per hour. I reckon that it would run for hours with a stand alone 12V car battery.
I'm not very good at electronics, but as suggested, a blocking-diode would , effectively act as a switch between a solar cell and a battery . Now, if you connected the pump via a suitably -rated zener-diode (in series, IE battery pos- switch,-diode (on a heat-sink) -pump. ) you'd have a controlled supply to the pump, a "safety-valve" on the solar-cell...... now add another heat-sinked Zener in the solar-cell output and you have a regulated charging-voltage to your battery. Fit and forget ,switch pump as required battery automatically topped-up whenever the sun shines enough. The components are as cheap as chips. pun intended. postage/handling likely to cost more!

Would it work?

RS not cheapest but fantastic service...Farnell and Rapid are same group, different speciality-areas. Rapid are another. sourced an oddball lead-acid from them, for a digital weighing -scale.
Just a quick update.

The nice man delivered a NP4-6 Yuasa 4Ah 6v lead acid battery today. Taking my courage in both hands I snipped off the solar panel, attached a crocodile clip to the two bare ends leading to the pump, clipped them onto the fully charged battery and stood back quickly, anticipating a 20ft geyser or similar.

No such thing happened. The little cascade thing burbled away happily come shine or cloud, just as intended.

For now that does the job, what Sandra wanted has been achieved. We'll see how long the battery pumps for before we decide if mains recharging once in a while is a chore or not before worrying about re-purposing the solar panel as a battery charger.

Thanks for all your help

Rob P
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