The pump is -probably- a 24V diaphragm pump. You can get them on ebay for around 20 $/EUR (and you get a more powerful one). The spray gun/rod you can buy for 6-7 $/EUR. Then you can get a tank (repurpose an old container or buy one for another 6-7 $/EUR) and you are set. I did one a few months back, using my parkside battery. I even got diligent and added a small module/board for low voltage protection for the battery (another 5 $/EUR).

This sprayer can be used with insecticide / fungicide? The filter inside the tank/container won't be cloged or it can be taken out and cleaned? I would like to use this kind of sprayer on my fruit trees with insecticide / fungicide mixture.

Can you verify that the brushed motor in this machine has NO cooling fan? It looks that way in your video but it is not easy to see thru the motor holes to be sure.

Is it possible to change the water pipe? And put a longer one? Or maybe it's too complicated? Thanks