You can buy the parts (including the casing) then install yourself or you can contact Liu Liang for a complete assembly.
- Clemence
Yes, all of these come in kit form but they do offer kits now days that make it easy.
When I was searching there was a drastic price increase for a ready made all in one unit and they had much lower specs. For the same price I got a 15A power supply pre-made units only had ~3-5A, which is almost useless for flashlights.
Does anyone happen to know why the typical cheapie bench power supplies, like a 30v 10A, is limited to 10A even when the voltage is turned way down to like 8 volts?
Then we have the DPS5020 which can take that same 30v 10A and put out 20A at say 12v.
I’m not really understanding that. Does the DPS 5020 just have better circuitry in it? Is it a better design overall?
I’m considering buying a cheap 30v 10A bench supply, that can actually output those numbers, and then mount the DPS5020 controller on top of it. I’d mount the electronics of the DPS5020 inside the bench supply case.
I could reroute the output wires of the bench supply to the DPS5020 then route the output of the DPS5020 back to the original output terminals.
So I would power up the bench power supply and set it’s output to a bit more than I need, maybe leave it at 30v 10A, then do the actual controlling through the DPS5020.
Yes it costs a bit more, but I would have a nice looking enclosure in the form factor I want plus have a decent power supply for the DPS5020.
Just a thought.
Maybe their circutry can only support up to 10A before failing so they limit it by that number.
The same way RDS5020 can’t output more than 20A if you use 8V.
RD circutry is better I am sure, but goes by the same principle. There is max current that can be used on both devices.
Not sure what part confuses you…converting 30V/10A to 12V/20A?
One reason for fixed output current can be because it is a linear supply. This means less electric noise on the output current, but more wasted heat (They usual have some transformer taps or use a SCR/Triac to regulate the transformer).
In the case of the DPS series, they are limited by the fixed output current. This is mostly due to current being much harder then voltage to control and the components are rated for that amount of current.
Other cheap power supplies are not so good and will not support the full current / voltage range except under ideal conditions.
Your best idea is to get a cheap fixed output power supply, like a 24v or 48v unit and then connecting the DPS unit to that.
I have 1 DP unit built inside an ATX power supply, it works great but is limited to 11v output. They have buck/boost options now though that could boost the power.
I have another DPS5015 setup with an old 48v server power supply that I use for most things and have no complaints. Although the ripple voltage is higher on this one it does not effect most things we do with flashlights.
The part where one brand (cheapie) is limited to 10A regardless of voltage.
It would be nice if instead of 30v and 10A (300 watt), a cheapie bench supply could also do 8v and 27A (also 300 watt), but it can’t.
I really don’t know much about bench power supplies. I want to learn, though.
I assume the DPS5020 is a switching type due to its small size, light weight, high efficiency and no big coil.
I come from an automotive background, so I know how an alternator generates AC voltage then it goes through a bridge rectifier (3 big diodes, sometimes 6 to improve reliability) and a voltage regulator to get 14-ish volts DC. I guess this more closely resembles a linear type power supply? I’m not sure.
Current is basically always going to be the limiting factor.
Voltage is really easy to handle, you just pick some higher rated components that cost a little more and you can handle higher voltages easy.
Current on the other hand is what makes components heat up and there is no real option for handling higher currents other then getting beefier and bigger components. This can drastically increase the cost and complexity along with needing changes to the entire design.
Same reason that a lot of the older driver designs we used to use worked fine for low currents of ~5A but have major issues when we try to run them at 15A.
The DPS is indeed a switching power supply.
Overall the DPS series is the best bang for the buck that I could find by a long shot for high current power supplies. Most cheap power supplies are limited to around 5-10A max.
This is the supply I used in mine. Seems to work great. https://www.aliexpress.com/item/Single-Output-Switching-Power-Supply-Transformer-Ac-110-220V-to-Dc-60V-17A-1000W-for-CNC/32834100045.html
I haven’t pushed to the upper limits yet but at 10 amps it had no problem.
I used this enclosure. https://www.aliexpress.com/item/KINCO-250-x-190-x-110mm-Metal-Electronic-Enclosure-Project-Case-DIY-Power-Junction-Box-Case/32900527650.html?
Took the enclosure off the power supply and mounted it in the new enclosure along with the DPS5020. Added a 80mm case fan to get more air in and out.
It did take a little enclosure modifying to fit everything and be functionable but it’s doable.
Not exactly cheap, but like TA says for the money and output power, there’s not anything else going to touch it.
If I could find a proper enclosure cheap enough I might go that direction. Unfortunately, the cheapest, and only, case I found in the form factor I want is $130 shipped. This one.
This is why I think it’s better for me to just buy an existing bench power supply, like a cheap 30v 10A, and convert it.
IDK, I’ll keep looking around for a case.
I don’t know if this might be something that would help but I thought I would post it as maybe a option for some.
The old Xbox 360 power supply (brick) that can be purchased used for a few bucks on ebay might make a good low voltage power supply.
The 203 watt model will do 12v at 16.5amps on the output. I use one to power my Icharger, its worked great for several years now.
You have to do a little rewiring buts it’s very simple. Lots of info on google. Xbox made different power models so be sure and check to get the one you need.
This is just a reference to what your looking for, you might even find one cheaper or scavenge one from around the house. 
https://www.ebay.com/itm/Genuine-XBOX-360-203W-Power-Supply-BRICK-ONLY-Tested-Clean-Con-Fast-Shipping/223241682370?
But both are current limited regardless of voltage, that is what I’m telling you.
It just happens DSP5020 has higher limit than cheap one you were looking at.
DPS5020 will give 1000W at 50V 20A and 100W at 5V 20A. It cant go above 20A. It’s the same thing as cheap supply.
I am not sure what you mean by convert it?
Using a bench power supply to power another bench power supply is not a great idea. You are over-complicating it and it will cost more for no benefits.
Better to use a cheap power supply like this 24v/10A model: https://www.ebay.com/itm/5V-12V-24V-48V-Power-Supply-Driver-AC110-220V-TO-DC-Switch-adapter-For-LED-Strip/372130850519?hash=item56a4ba26d7:m:mC4Xfig00JRLboPrqg48VKQ:rk:2:pf:0
To power a DPS unit of your choice. Then just build a case for it out of wood if all else fails. I just have my DPS unit in a small little acrylic case on my desk and the power supply under the desk. I actually have a prototype acrylic case left over here, it cracked when I was putting it together but could still be made to work if you don’t mind the aesthetics.
This should handle almost any flashlight task you want, I rarely exceed these specs even in my extreme builds, and in those cases I exceed my existing setup by a lot.
To be blunt, I don’t like the looks of any of the homemade enclosures in this thread, including the blue store bought one. I also don’t want a wood case. I want a proper case in the basic shape of narrow and long to take up less space on a bench. Like in the link I posted. Aesthetics are critical to me.
Buying a bench power supply and converting it will cost maybe $80 plus $50 for the DPS5020. $130 total.
Buying an empty case and seperate power supply will be $130 and $50 plus $50 for the DPS5020. $230 total
So it actually costs Less.
Here is the conversion process from a few posts above.
Since it might cost me $230 to build it up custom, maybe I should just look for a bench supply that can already do 20A?
Can’t you just buy the one RDTech sells?
It’s quite small, but it is a very nice aluminium case:
Another thing I actually do to get the output voltage up is putting in series laptop power supplies.
By doing so, I’m able to use a 39V power supply for tasks that I need to do with higher voltage, and just use one for lower voltage uses.
Be wary to use similarly specced power supplies. I “dumpster dove” and found 2 laptop power supplies that were working very well.
No, I have to have one assembly with everything inside.
Since this is all about cosmetics you will just have to spend the money for the look you want it sounds like.
For the prices you are looking at spending you might be able to find a pre-made unit with 10-15A of current. You can search ebay for used units for example although more then 10A is hard to find.
Using a bench power supply to power another bench power supply is not a very good idea as the ripple and voltage spikes of each unit could easily interfere and cause issues ranging from small to major. It is simply a recipe for problems unless you get quality units, in which case you are ruining a good power supply to DIY it.
For reference my entire setup costs around $50-$60 for 15A of current IIRC.
After a lot of looking, I found a pretty decent metal case for only $34 shipped from the USA. It’s a bit larger than I need, but no big deal. It will fit a 240 x 125 x 65 48V 10A psu no problem. Maybe I’ll give it nice coat of off-white paint.
Now to hunt up some nice front and rear connectors for power and leads, etc…
Do you think I can use these to test for over discharge protection in lights (reduce voltage and see when it shuts off)? I use one in the lab but should get one at home too.
Yes, it can be used for this, although the relatively high ripple voltage on the higher current models can cause some false readings for things like LVP. My older/lower powered DP3005 has lower ripple and works better for this kind of thing if I have issues with the DPS5015.