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Add a battery to a small solar powered pump Answered

Hello all, I’m new to the website and was after some help/advice l! So I recently bought a small solar powered pond pump to turn it into a little filter. It works well baring one thing, if there’s no sun it stops! I was wondering if anyone could help me by recommending a battery or something that I could add it to make it run for some time if there’s no sun. I have attached a picture of the specs from the pump/solar panel, any advice would be great :)


Josehf Murchison

6 weeks ago

You might find this Instructable helpful
These solar circuits use the solar cells limits and a diode as the charge controller.
If you want the pump to run all night long you will need a solar cell 12 to 14 volts 5 watts, it may say 12 volt but be as much as 14 volts.
A 1N5817 diode to regulate the charging.
12 volt 10 amp hour battery.
and a voltage regulator set for 10 volts to run the pump.

Jack A Lopez

2 months ago

It is not clear to me what role the pump will play, in this, what you call, "little filter" contrivance.

Are you planning on using the pump to lift water up, against gravity, to some height, from which the water falls through a filter?

I mean, if that is the mechanism by which your filter is made to work, then the height, multiplied by volume, of your lifted water, is a kind of stored energy, essentially stored work.

A check valve might be helpful, if the water has a tendency to drain downward through the pipe, whenever the pump is off.

What I am saying is, additional energy storage, like a battery, is unnecessary if you are already storing energy, in the form of lifted water, especially if that particular kind of energy, lifted water, is what is needed to drive the water filter.

Lukeyyy93Jack A Lopez

Reply 2 months ago

Sorry my explanation wasn’t the best.

Basically I purchased a pump that comes with a solar panel, the pump is placed in the bottom of the pond and is connected to a filter that I made (it’s just an acrylic box with 3 types of filter media that the water passes through before it then overflows).

I added a one way valve after the pump so that water doesn’t return from the filter as gravity would indeed cause it to flow back out of the pump.

As for the filter volume it’s a 100 x 300 x 200mm box, and it’s a little above the level of the pump so the water does have to travel a little up hill about 6in at most it will have to pump it.

Jack A LopezLukeyyy93

Reply 2 months ago

Adding a battery, especially a rechargeable battery, tends to add complexity to a design, and adding complexity is only worth it, if the complexity can give some significant improvement in performance.

In particular, for lithium-ion and lead-acid batteries, those kind of batteries get into trouble when over-charged, or when over-discharged. So for those kinds of batteries, some kind of crude intelligence, a charge controller, or battery management system (BMS) is needed, essentially to protect the battery from itself.

Storing energy in a big capacitor might be a worthwhile approach, if the amount of time without sun is measured in seconds or milliseconds.

But if you need the thing to run for several hours without sun, that would likely require a battery of some kind. But why do that when the product, the filtered water or whatever, can be stored for hours too?

There is an English idiom, "Make hay while the sun shines."


I think maybe it applies to other activities, besides making hay.


3 months ago

How would you charge the battery?
When the sun is out the solar panel can only provide enough power to run the pump but not to additionally charge a battery.
You need either a panel big enough to do both or add a second panel for the battery.
Either way you also then need to add a suitable charge controller.