I made the 27 volt generator by cutting a 1 ounce silver bullion bar in half, cost of the bar when I bought it was about $10.
I drilled a small hole through the two half pieces of the silver bullion as close to the long end as I could. I attached a thin one foot long 16 gauge copper wire leading to the positive & one leading to the negative terminal of the 3 batteries which I had snapped into place with one another leaving you with a positive terminal on one end of the & a negative terminal at the other end. Twist the copper wire tightly 2 or 3 times after you have inserted it through each end of the silver bars.
I used a wooden shim about 3 inches long by about 1/4" thick & drilled two small holes about an inch apart through which to thread the two wires that will be attached one to each end of the batteries whose terminals you have snapped together. Your little block of wood will rest on top of an 8 oz drinking glass, so make it long enough that it doesn't fall into the glass.
After you thread the wire through the wooden block, bend the wire 90 degrees such that the silver bars will sit at equal elevation inside the glass to within about an inch to the top of the glass. After you bend the wire a single twist to each of the two open terminals of the batteries.
Now fill your glass with distilled water keeping water below the point where you twisted the copper wire onto the silver elctrode bars, current will begin flowing between the silver bars inside the glass, you will see bubbles forming within a few minutes, if you do not it's because one of your wires is not tight enough either on the battery or the silver bar, or your batteries are mostly dead.
About 15 minutes after bubbles begin forming on one of the bars, you will see brown streamers forming & falling to the bottom of the glass, now you must stir the water about every 5 minutes with a wooden or plastic rod to beak up these streamers or you will accumulate large unusable particles at the bottom of the glass which you must filter later.
At this point it would be useful to remove a battery from the setup so as to reduce current flow to the electrodes, reduction in current flow keeps your silver nanoparticles from becoming very large & less usable for consumption, I actually go to using just one battery at this point which is about 1/2 hour into the process.
Just as soon as you barely see a slight yellowish tinge in the water, STOP. This will happen about 1 1/2 hrs into the process, if you have dropped back to using just one battery like I do.
If you notice black particles have settled at the bottom of the glass, just pour out most of the water into another glass down to the point of 1/2 an inch or so above the bottom of the glass such that those silver particles do not mix with the water you're pouring into the other glass. These black particles form when nanoparticles attach to impurities in the water, they're harmless but not useful for anything if you consume them.
The next day look to see if there are more small particles at the bottom of the glass, & follow the instructions in the previous paragraph, I do it whether I can see particles or not because they are likely to be there but are simply so small they can't be seen. You could use filter paper as well when pouring from one glass into another.
I try to stop my colloidal production before I see that yellow tinge in the water, that way I'm assured all my Colloidal Silver will come in under 20 ppm which is about the ideal concentration for drinking.