Need help finding a constant current DC power supply

I am working on a project that requires a variable DC bench supply. The range of 0-30V and 0-10A is fine for my needs.

The critical feature is being able to easily run it in constant current mode. I know. That’s easy to find. I am unhappy with most power supplies though. The ones I’ve tried either make you do a bunch of secondary button presses to switch the display and dials to constant current or they “auto detect” that you want constant current.

I am looking for a supply that is straight forward. In a perfect world there would be a dedicated switch to enable constant current mode and a dedicated dial and guage to set the current output. I realize that’s a lot to ask for so I would be satisfied with something that only has a switch to enable constant current. I am tired of it being a secondary function that you have to do a front panel dance to enable.

I am willing to hack together something myself. Mod an existing supply if needed. I would even accept a supply that only has constant current.

Maybe it is because I am old but I am tired of these front panels that dump every function into multi-function dials and switches. Give me a front panel full of switches, dials and gauges. I will pay for the convienence.

If anyone has any ideas or suggestions I welcome them. I’ve already purchased several supplies in my quest and so far no-joy.


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What is the use case for the constant current?

My experience with constant current options on supplies is to set a limit for protection and not for specific operation. In other words, CC mode is not the target current but the max current setting you are willing to live with supplying to your circuit.

It sounds like you want a true constant current supply that will adjust the voltage to ensure a specific current. I have not run into one of these before. Most supplies only have voltage reduction to prevent exceeding a particular current.

This is likely why the CC settings may not be the simplest thing to modify from a user input perspective. Since it is supposed to be a protection measure it shouldn’t be very easy to modify.

I am using it for electroplating.

I will have to see if I can find the manual for the supply I am using now so I can clarify what I have to do to switch it between the modes. If I remember correctly I have to press one of the adjustment dials to switch modes.

I think mostly what I am looking for is something that has distinct dials and switches. Not something that uses the same dials and switches for multiple features.

Something like this?

Jesverty DC Power Supply Variable, 0-30V 0-10A Adjustable Switching DC Regulated Bench Power Supply with High Precision 4-Digit LED Display, 5V/2A USB Port, Coarse and Fine Adjustment SPS-3010

It has a dedicated knob for controlling the current limit.

It is very similar to other units I’ve looked at. I suspect they all have the same internals. That one, like many others, auto detects if it should be in CC of CV mode. I would like something that lets me set it to one or the other modes instead of the unit deciding for itself.

Yeah that is the point I was getting at in my first response. For nearly all power supies CC mode is a protection mode for overcurrent and not a typical mode of operation.

Does the voltage also need to be constant for your electroplating?

For the nickle plating I’ve been doing the voltage can be whatever. I set the target current and the power supply should maintain that and adjust the voltage as required.

For example I might start at .5A and the voltage could be 5V to 6v. As I ramp up to 1A the voltage might go up to 10V. When I hit 3A the voltage might be 26V.

I have a supply that does this. It is just annoying to get it into that mode. What I would love is a supply that has a dedicated CC button/switch and dedicated course and fine current adjustment knobs.

I do lots of zinc plating with this power supply.

You are kinda thinking about this backwards. You need to set the current to be what the part requires due to surface area. It doesn’t care what the voltage is as you said.

Voltage and current are links with Ohms law. What happens when you plate your part is the resistance changes in that formula. So that is why you plate by current and not by voltage.

Now on to how current limit psus work. When you hit your current limit it scales the voltage down to satisfy ohms law.

How does this work in practice? You set the voltage to the max number on the PSU. In this case 30V. You set the current very low. I set it to the min output of the PSU.

Dunk your part and turn it all on. Then raise the current to hit your calculated current and let it do its thing. No reason to over complicate this :slight_smile:

“I am willing to hack together something myself.”

If you are willing/able to have an ‘unsafe to touch’ (i.e. lockout,tagout, autokill type of safety system), I’d suggest a ‘Capacitive Battery Charger’.

One example of it…

Yes, dangerous as hell, (non-isolated, and this guy didn’t add a fuse! - I also add a 15k bleed resistor and 2 LEDs across the caps, should it be unplugged/switched off mid-sine wave) but it works as a dirty CC source- perfect for de-sulfating lead-acid batteries. As this guy points out in the image- every 25uF = ~1A. (It fully regulates the current, in fact; the safest way to store this battery charger is to clip the battery 'gator clamps together).

I’ve likely saved a dozen batteries from needing to be replaced over the years. (Made one for my buddy who drives a semi- he is quite pleased at not having to replace them nearly as often- much pricier than car batteries, I guess)

Not sure how frequent or how fine you need to be able to adjust the current… I’ve got a few ideas if you do/and this idea doesn’t scare the crap out of you. :stuck_out_tongue_winking_eye:

(this just in- I’ve never thought of adding a variable transformer/variac before, likely because it would crazy unnecessary for fixing batteries, but for your process… And it would add a bit of safety being isolated)

Sorry for the ‘book’.

FYI- Where I ran across the plans for this, many years ago…

I should be clear. I already have a supply that I’ve been using. It has a CC mode. I’ve used it to create nickle plating solution and then plated objects. I set the voltage to 30V, then push the knob to get to the current adjustment and set that to my target current.

My quest for something that is better to me, that feels more satisfying to use. It isn’t really about functionality. It is about aesthetics. I don’t like how the supply works. I don’t want it to auto-detect operating modes. I want to be able to deterministically set it to CC mode and set the current limit and have it figure out the rest itself.

I don’t want multi-purpose knobs/etc. To me it is like multi-meters where you have to set the dial and then press mode a few times to get what you want. Sure it works. I just dislike having to go through that dance.

The PSU I linked has a dedicated knob for current control.

Again thinking about this as a dedicated CV or a dedicated CC mode is not the right way to go about it. Voltage and current are linked.

You set the maximums for both values and let ohms law solve it.

In the case of plating. You set the voltage to be as high as you can and set the current to your plating current and the power supply will regulate the voltage to keep it in the current limit. This is a “dedicated” CC mode.