Power and solar panel for pump

[dodoheidi]

XNUMX-XNUMX-XNUMX!

I have a small question of physics, finally several. and I will take an example, the one that occupies me now.
I want to buy an immersion pump to raise water from a well (pump said to be 30 watts.)

I do not plan to associate a battery with it.

it is supposed to work "over the sun".
first question, to which I answer, finally I believe! when a device is advertised as 30 watts, does that mean that below this power, it does not work? at all?

then, I have the worry of choosing a solar panel.
a priori 2 hours of operation per day would be more than enough for me.
so is a 30 w panel sufficient or is it better to take a little more powerful?

then when I looked at the characteristics of solar panels. For a 30 watt, the maximum voltage can go up to 18 volts. but in this case, won't the pump be damaged?

Thank you for your help!

[dodoheidi]

the pump being a 12 volt pump of course, I forgot to specify it.

[dedeleco]

You have to see the precise characteristics of each, panel and motor, with great care.
When starting the pump may require more than 30W, to unblock ?, and the no-load voltage of 18V? of the panel decreases with the current requested by the pump.
Finally, the sun is not always at its maximum, battery facing the panel, the voltage will often be too low without battery and buffer regulator, to deliver starting power.

[Forhorse]

Generally, pumping applications over the sun are more complex than they appear.
It is often essential to associate a little electronics and / or a buffer battery.

On another forum someone had proposed the diagram of a small MPP tracker intended precisely for the supply of a motor directly by a solar panel.
The subject can be found here:
http://forum-photovoltaique.fr/viewtopi ... 40&t=18472
If you know a bit about electronics, you can easily adapt and make it for your pump.

Otherwise you must either use a buffer battery and a charge / discharge regulator, or create a small comparator circuit which only energizes the pump from a certain panel voltage, meaning that it is capable of producing sufficient power. power to start it. Otherwise, it risks quite simply burning out because a motor which does not turn but which remains supplied by a voltage which does not allow it to be started behaves like a simple resistance (no EMFC) which generally results in its destruction by overheating.

[dodoheidi]

Thank you very much for your answers, this opens up avenues for me, being a novice in the matter.
unfortunately, I don't know anything about electronics, but I'm going to look into it anyway.
the idea of ​​associating a battery for the moment bothers me (limited lifespan and not very ecological), but it is perhaps the best solution. Especially that in this case it is then possible to use a smaller solar panel, which will be cheaper, since the battery will store?

[Forhorse]

Especially that in this case it is then possible to use a smaller solar panel, which will be cheaper, since the battery will store?

Not at all !
Unless you want to stick to a very limited operating time during the day. But in this case the number of cycles of the battery will quickly be very important and its lifespan will be very short.
The amount of energy produced by the panel must still be equivalent to what the pump consumes.

Do you already have the pump? and if so, have you already made functional tests? just to validate the absorbed power and the operating time for the desired volume ...
Because in pumping, apart from making learned calculations, the result is often lower than the pifometric estimates that can be made.

[dodoheidi]

Okay.
for electronic editing it looks really interesting, but way too complicated for me.

I actually have few needs.
it would be a question of raising a well (lifting height 5 m, in the driest season) a quantity of water of 100 to 200 l. let's say take 200l.

the pump I found: LVM 107 has these characteristics:
12v, for 5 meters, I believe 5l / min. , 30 watts (by the way, does anyone know of one that consumes even less, but is still able to lift the water 5 meters ???)

in fact, I'm telling myself that in 40 minutes it's done!
I can put a water reserve of 800 liters (after taking out too much water is not the best, since it will stagnate)
so I can also only run the pump 3 hrs, every 4 days.

what solution do you choose for this type of problem? so that the pump lasts as long as possible and that I have as little supervision as possible?

[dodoheidi]

to finish answering, so I don't have the pump yet. I did some research and decided on the LVM107, but if anyone here has any other ideas, I'm open to any advice!

From what I'm starting to understand, for the life of the pump and battery, they'd better run 3 hours every 4 days, rather than a little every now and then during the day?

which also means, that the solar solution, is perhaps not in my case the best solution?

So, I have to buy a 12 volt battery (or a rechargeable battery?) and plug it directly into the pump every 4 days for 3 hours of operation? would that be best? while making sure that the pump is running (because my battery will run down) so as not to burn out the pump?

[dodoheidi]

I found a charge / discharge regulator at 30 euros.
not sure you understand, he can put himself between the battery and the pump to protect the pump?

12V battery - charge discharge regulator - pump?

[Christophe]

It takes a bit more precision to answer correctly.

Do you need to pump all year round or only in summer or only when there is great sun? How are the 2 hours of pumping regulated?

This question is fundamental to sizing the solar power you need.

If it's only summer and 2 hours a day then a 20W panel should be more than enough ...

a) Need = 2H * 30W = 60Wh
b) Resources = 20W * 5h of average sunshine per day in summer (more in reality) = 100Wh - some losses = ok

If it is for the whole year, the solar power will have to be much higher (and the investment much higher)

You will find some small solar panels here: https://www.econologie.com/shop/solaire ... aique-c-35

If you use a battery, you will need a regulator to protect it from too deep discharges.