Any opinions on this power supply? Tenma 72-10480 (0-30v, 0-3A, 1ma increment)

[Turbidaceous]

I have placed an order for this and I am hoping to god it will be good. It has 1ma readout, can do constant current and does up to 30 volts. I saw a YouTube video of a bloke demoing it and showing the constant current aspect. Plus he was modifying it real-time which seemed like a good capability.

I would welcome any opinions: https://cpc.farnell.com/tenma/72-10480/power-supply-1ch-30v-3a-adjustable/dp/IN06822

The bloke on the video said it is a linear supply which is not documented anywhere but he said it was a really good one. I am just hoping it is good enough for making colloidal silver without me having to babysit the ammeter. I don't mind measuring current as usual as long as what ever it reads out stays stable so I can determine the strength.

[cfnisbet]

It seems an excellent PSU. You should be able to do very well with this Power Supply.

[Turbidaceous]

Oh that is good news. That link is the cheapest I could find it also. I will still be interested in the tutorials and what not, maybe there will be cheaper or good simple ways I can show other people to make it. Here's the YouTube video I found: https://www.youtube.com/watch?v=BfNfgki5-Fw

[Turbidaceous]

I have it running, I set it at 30v 15ma. I start it and it reads live voltages in the 20v range which is good and the current says 13ma. But when I measure it with my multi-meter the miliamps are dancing around 15.6 - 15.89ma. Is that normal? Should I calculate by an average of what my cheap multi-meter is telling me or should I calculate time based on the 13ma the front of the power supply says? I am confused.

[Turbidaceous]

So is it normal for constant current to dance around a certain value? I figured it would be static and unchanging but this is dancing around the miliamp range I mentioned. Does that mean this power supply is no good for making colloidal silver?

https://www.youtube.com/watch?v=1eYbPiCTvDA

The power supply keeps clicking sometimes repetatively. Not sure if that is normal for a bench power supply. Might be my hotplate clicking, not 100%. But the miliamps dancing around is concerning me.

[GO2GUY]

Trying turning it down a few notches.  . . from my limited experience these devices they can only hold steady once that limit is achieved, so in other words if you set it it to 20ma but the resistance of the water and electrodes only allow for 13ma well then the number will dance all the way up until the point that they hit the constant current target point and then it should hold steady.. . . This may or may not be related to your situation but its worth a try.  set it to a low number like to 5 or 8 ma just for testing purposes and then check the output and see if it is holding steady. . . the output will still likely be a tad higher since it seems to be slightly miscalculated . but at least it might solve your dancing probelm. . . Good luck

[Turbidaceous]

I will try that for a short burst after this main run is done, I don't mind it being a tad more potent because of testing.

Could me using 0.2mm super thin silver wire for the cathode possibly cause the fluctuations? I mean if it's ridiculously thin and flimsy, could a bit of movement of it cause fluctuations in current?

edit. I tried setting it to 8ma, but the power supply said 6ma and my multimeter was dancing around 8.5 - 8.8 ma again.

Also when I pulled out the rig, again I saw what looked like a little pool of silver woft throughout the water, even with this large electrode and only using 15ma. I have no idea what is going on. Hopefully someone can help me figure it out.

THanks

[GO2GUY]

in theory it shouldn't as long as the power supply is well with in the limit mode. what i mean by that is the water has a has a current ohms reading and that ohms reading lets you know the total amperage the water can facilitate at that current point,  you can check this by measuring the ohms of the whole set up and then put that figure and the voltage into the formula of ohms law and you will get your answer.   I believe this is the correct formula I = V/R
The current I in amps (A) is equal to the voltage V in volts (V) divided by the resistance R in ohms (Ω): 


 remember the water is constantly decrease in resistance as you add more and more silver . .. . .  . . . so if send  30v with and unregulated/no current limit and its at like 20ma naturally due the set up resistance and then you regulated it to 10ma thats a large difference so I highly doubt a slight movement will make any difference at  BUTTTTT if the unregulated point thru ohms law is at lets say 10ma and you regulate it to 11ma, then there is movement in the electrode this could potentially cause fluctuation because its not actually under limit and/or if it is  it is bouncing in and out of limit.  your goal for consistency is to be well with in limit, Id say at least by 2ma that way under no circumstances it will go out of limit and it will stay as consitant as your current power supply will allow

[Turbidaceous]

I also tried 20ma and I forget the numbers but it was similar dancing around. So I have tried 20ma, 15ma and 8ma and they all dance around. All were at 30v. I also tried setting it to 27 at some point during the batch and it made no difference to the miliamps dancing around.

[GO2GUY]

well in that case it seems its just the tolerance of the power supply. . . . as long as its well with in limit, it shouldn't be doing to much of the hot step boogie. . . do you know what your non limited amperage is at ?  in other words set the machine as high as it goes, see what the actually output is on your meter , as long as you stay under that aka the formula of I = V/R you know its actively limiting the current  and your machine is doing the best it can. . . HOWEVER now that i sit and think about it its actually seemingly pretty good considering 8ma means a thousandth of an amp or 0.008 so while its dancing arround between 8.5 and 8.8 ma  This is a tollerance 3MICROamps!!!!!!!!!!!! aka 0.0003 tolerance. . . this seems pretty darn good considering, . .  but who knows maybe im wrong  it would be interesting to see how much better high end power supplies do .Mine only measures to .000 So i have no idea whats going on in the in the Micro amp region??. . .

[cfnisbet]

I think this might be worth buying as an experiment. Seems a good unit.

[Mer2112]

Hi There,

What are you using for the anode and how far in the water do you have your .2mm cathode?

Are you using a stirrer that is causing the water level around the cathode to ripple/vary?

Have you tried raising the cathode up and down to see if that helps stabilize the mA reading?

As an example, I use a Silvertron Mini and even though it's a constant current regulator/supply, you still have to adjust the cathode depth to its optimum level so it'll stabilize.

Can you post a quick picture of your setup so we can see how you have it arranged please.

We'll figure this out. 
 
Eric

[Turbidaceous]

Please ignore the mess

The unit seems very good though it might be me needing to tweak cathode height. Also, my white pool issue goes away when I pull the electrode system out of the water quickly while it still is powered on. I just made the best 20ppm I have ever made. Now I am in the middle of using 20ma to make some 80ppm before I have to rush out for a haircut

My anode is a 1.5mm thick 35x90 mm fine silver anode from Argex. Cost me £35 total. It's pumping out 20ma right now with zero smoke, I bet I could go higher but with Amazon messing up my Repsol distilled water orders, I don't want to experiment too much with the water I have left. Next pay day I will probably buy from the other company mentioned on here ACS or something, I bookmarked it somewhere. I didn't really want to make any more 20ppm but after last night's 1L of 80ppm seemed ok after removing the electrodes as mentioned above, I felt I had to make 1 batch of 20ppm and visually compare to my best ever cold production which truly was perfect. My 20ppm hot test came out perfect, absolutely perfect. So the only change this 80popm batch is I am using 20ma instead of 15ma.

[Mer2112]

Is that a stirrer or hot plate?

[Turbidaceous]

Just a 1500w hotplate: https://www.amazon.co.uk/gp/product/B0019MSXGG/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

The convection currents are enough to perform the action of what a stirrer would do, as long as you don't crank the current up too high. I am able to do 15ma with my 35x90mm anode easily and it JUST seems fine with 20ma. But calculating the max current I could do all the way up to about 40ma if memory serves but I would need strong stirring and a hotplate is not likely to tolerate that.