Portable Bench Top power supply using the DPS5015 - FINISHED, for now

Batteries and Chargers Rechargeable Batteries
1

I first heard about the DPS5015 6 months ago here.
Budget friendly adjustable bench Power supplies perfect for testing LED’s and other uses!
I was skeptical of it’s performance at first, but was quickly convinced that this unit is the real deal.

So I recently ordered one.
It seems everyone is driving it with plug in power supplies, I thought I would try something different. I will power mine with Li-ion tool pack batteries.
For a case I will use my original Ridgid Ni-Cad 18V, dual bay battery charger.

(I have since cleaned this up of the dirt and grime you see here) :slight_smile:
My old Ni-Cads have worn out and I have converted to the newer Li-ion batteries. My old tools are backwards compatible, but this old charger is not able to charge the Li-ion batteries. Time to repurpose it!
For a power source I plan on using a 40V Ryobi yard tool battery.

This battery pack contains 20 18650 cells and is a BEAST. capable of easily putting out in excess of 20A.


I am going to use the old Ridgid Ni-Cad charger as a host for the DPS5015 because with a slight modification, the 40V Ryobi will plug right into it.
This dual bay Ridgid charger was originally designed to accept 12.0V, 14.4V and 18.0V Ni-Cads. Circuitry inside would figure out which pack was plugged in and it would charge them accordingly. Note that Ridgid designed all 3 of those different batteries to have the same plug and socket setup. The tools for each voltage had a system of keys and slots to prevent the wrong battery being used in each tool.
Believe it or not, there is a lot of commonality between Ridgid batteries and Ryobi Batteries. They are made by the same manufacturer!
Here is a Ridgid 18V battery next to the 40V Ryobi. Notice that the plug system on each is the same.

Confident that I could make it fit, the first thing to do is gut the charger.
Remove the screws. It takes a security torx bit to remove them, Harbor Freight sells a nice set, cheap.

What’s inside, someday I will investigate that power supply. 2 channels of nice.

There is a fan and 4 LED assembly that I may be able to reuse in this build.


Previously, the 40V Ryobi would slide into the socket, but something was preventing it from sliding in all the way. I had to find out what I had to modify on the socket in the old charger. I do not want to modify the battery. The battery belongs to a yard tool and I will continue to use it for that and charge it with it’s included charger.
Here is what is preventing it to slide in completely. The flat black square key on the charger is preventing the battery, gloss black, from sliding in all the way.

I have to remove part of this block.

Just enough removed so that the battery will fully insert.

The unit with the battery fully inserted. I plan on mounting the controls for the DSP5015 where the left channel socket used to be.
I haven’t yet decided where to put the binding posts.

And if I wanted, I could still power this with the 18V Ridgid packs. This is a 2.0Ah pack. I also have some 4.0Ah packs.

And even this 24V Ryobi pack will fit!.

All I can do now is wait for my DPS5015 to arrive and wire it up :slight_smile:
BTW, in case anyone was wondering, each battery pack has low shutoff circuitry. I could run this until the pack shuts down. I may want to add a separate DVM to monitor the input voltage while it is in use.

I’m hoping there are no gotchas waiting ahead for me. There usually is when going off the beaten path like this. :person_facepalming:

EDIT:
Arranged the words to the title around a little.

May 7th, 2017
Well I received my DPS5015 about a week ago. Only now have I had the time to wire it up.

As I am right handed, I decided to mount the controls on the left side of the case.



Rough cut first then file work.

As I had mentioned, this case has plenty of ventilation both top and bottom halves.


All wired up and ready to go. The color of the bezel sort of matches. Can’t say so much for the colors of my binding posts.
I have had these posts sitting around since the early 70’s. Back then I used to frequent the surplus dealers in and around the Boston area. I was NEVER able to find matching Red and Black 5 way binding posts! The ones I see for sale today are not of good quality, or they cost way too much. Purple = Red and White = Black.

IF I ever do come across Red and Black binding posts, this project will be upgraded.
Here it is with an 18V (21V fully charged) 4Ah Ridgid pack.

Here it is set for 12.00V with the current limit set to 15.10A.
Connected to 2 - 2.2 Ohm resistors in series.(4.4 Ohm), it pushed out 2.69A

Connected to a 2.2 Ohm power resistor is draws less than the current limit, 5.38A. Voltage was maintained at exactly 12.00V :slight_smile:

Next I set the current limit to 2.00A while leaving the voltage set to 12.00V
This time because the current limit had been reached, the voltage fell to 8.90V

Everything is working just as it should :+1:
Left to do is mount an input jack for a 19V, 3A laptop supply. The hole for the old AC cord screams out for that jack to be placed there.


I will have to use a SPDT switch for the 2 inputs, battery or laptop supply. That switch will also double as an on-off switch for the battery. There is a very slight drain on the battery when not in use.
This unit is very nice to use. The slope on the control module makes it easy to see and adjust and the binding posts below it are out of the way, yet still easy to connect.
And the performance of the module is top notch.

2

Very cool. Love how you use stuff that is readily available. For folks that don't have the exact items, you show a thought process that can get one to the same end. Got the popcorn on slow cook. :)

3

Thanks
Yeah, nothing here says you have to use an old Ridgid charger. I don’t know how well it shows in the pictures, but that case is extremely well ventilated. One use for the final product could be a car boost charger.
Also, I am calling it a bench top power supply, but it could be used anywhere. Just dial in the voltage and use it for lots of things.

4

There is just so much stuff going on here at BLF. I completely missed that thread. :person_facepalming:

5

Just in case you didn’t know, the DPS displays the input it receives down the bottom of the screen. Not a very obvious display so I understand if you want a seperate larger display.

6

Following. I’ve been putting off getting a bench power supply
for testing purposes so I’m glad to see discussions on here.

Not to digress from the OP topic but could someone point me
to any good repositories or beginners guide on the subject?

7

That’s a cool take on the PS!

I also love how flexible the DPS is. If I don’t need high voltage or output for USB testing for example, I use a small battery pack to power it.

8

But….why?
The entire point of a power supply is to not have to use batteries…………
And you’re powering the power supply with batteries.

9

So you can carry one battery and have any voltage you want avalible, with current limiting, at any place you want, miles from any mains power if need be.

10

Float charge is useful for some batteries, however the use of the DPS as a battery charger whilst powered from batteries itself is kind of limited. It may have some uses as a portable charger but it has many other applications and these I would argue are more relevant for many.

11

This is a great idea, a portable “bench” power supply!

That 40V battery is nice as well, it should give you some good runtime as well.

FYI, they also sell a buck/boost version of the DPS now that allows for it to both reduce and increase the voltage. So you could set it up to work with a lower voltage input such as a 12V car battery and it could raise the voltage up to 50V. It has less current abilities though but I am sure it has uses for someone. I would use it to work off of a 12V ATX power supply for example as they are cheap and easy to find.

12

So you’re doing this because you need a portable power supply?
Ok, cool.
I just charge all my stuff at home, where there is wall power.

If I need power elsewhere instead of going battery -> charger -> battery I just connect the first battery to the device and save a bunch of conversion/charging losses.

13

If the point of this was charging batteries it would have been much more effective to use a hobby charger with proper temperature monitoring, variable current and voltage, cell monitoring, balance charging, and all the other important stuff that you should have in a charger.

Charging batteries by just sending constant current at their peak voltage to them is a 20th century way of crappy charging. Old and outdated.

14

Not for battery charging, that’s just one possible use, gauss directed that way. :person_facepalming:

I can use it to power individual boards on equipment for fault diagnostics at remote sites where mains may not be useable.
Loads of reasons, if you can’t see a use it doesn’t make it a bad idea, others might find it helpful although it’s hardly likely lots of people have an application.

15

So how are people powering this power supply? I can’t think of a single source of 50VDC except a pile of batteries.

16

meh. $36 for cables and boards and then you need to buy a SMPS to connect to it too? No thanks. It’s not portable at all with all that raw PCB and cables dangling. And building a box for it all would be time consuming and huge. I don’t have a use for it.

17

i can think of a few times this would have been handy.
beats the hell out of lugging my hp 0-60v 35a rackmount somewhere.

18

^ You didn’t build the required SMPS into it. And if you used a laptop power supply or similar you would not have the watts this thing is capable of. For $55 you can get a 30v 8A power supply on ebay that plugs into the wall and has a case. CC and CV.

19

As I said, I don’t have a use for it. But calling it ‘quality’ or ‘powerful’ because you can ADD a quality/powerful power supply seems misguided.

20

We’re all ears. Please tell us why gauss163 declares it powerful and quality.