Tekpower TP3005D-3 disappointment

[skyjumper]

Hi All...

As a long overdue update to this thread:

https://www.eevblog.com/forum/testgear/looking-for-a-bench-power-supply-142871/

I made due with an older supply back then and more recently I bought a Tekpower TP3005D-3:

https://www.amazon.com/gp/product/B00HX0UYBK/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

It arrived today, missing a power cord. It's a three channel supply, with a fixed 5V, 3A channel and two variable channels from 0 - 30V and 0 to 5A. I hooked it up to my EEVBlog multimeter and found that the displays for both voltage and current are way off, like 0.1 - 0.25V and as much as 23mA. Worse, the slightest turn on the knobs makes pretty big changes in the output.

I'm considering just sending it back, but before I do I thought I would ask if all supplies in this price range ($US 199) are going to have similar issues. I'm a bit disappointed and wondering if I was expecting too much. Yes?

Thanks...

[ataradov]

Yep, this is pretty typical for this type of power supplies. Especially twitchy controls. I would never use a power supply without digital controls with lockouts from accidental presses. With knobs it is way too easy to brush against them and mess things up a lot.

And yes, 3 channel supplies at this price point will probably be not great.

Although you can get two Korad KA3005D for the same price, and they are decent units.

[Mr. Scram]

There are dual power units too.

[jiarui]

I have a 3A version of this supply. In my case, the meter (volt and amp) are pretty accurate.  The dial is very sensitive.  I ended up adding a second pot on each channel. There are spaces on the front panel.  These two pots gave me finer adjustments to the voltage. 

I also have the Tekpower TP3005P (single channel, 30 V 5A, digital control).  I like this one a lot (with output on/off,  a couple of memory for voltage/current). It is also controllable through the USB port.

[skyjumper]

The KA3005 looks pretty cool, the current version is P. I'm willing to spend a bit more for something that's useful. What else should I ook at for say $300 US or less? How is the Siglent stuff?

[sambonator]

I'd go used on ebay... I started off with a Pevono PS305H for $45 shipped on Amazon when it was on sale with code from Techbargains.  I thought it was an ok supply until it ate two of my multimeter fuses.      

Then finally got a used Instek GDP-3303S for $170 shipped on eBay.  I had to keep waiting and making offers until a quality brand unit showed up from a seller willing to bargain.

Sam

[bitseeker]

The KA3005 looks pretty cool, the current version is P. I'm willing to spend a bit more for something that's useful. What else should I ook at for say $300 US or less? How is the Siglent stuff?

The P version is programmable via USB. The D version is not (and, hence, costs less).

For $300, there is quite a variety of used A-brand power supplies available in the US (your profile doesn't indicate your country, so I'm assuming your location). You may even get them at a better price via local sources such as Craigslist or equipment liquidators.

[skyjumper]

I am in the US, I'll do some checking on Craigs List and Ebay. I just got a new project, but I have a little time.

[skyjumper]

I assume that if I got two separate units, I can't use them in serial or parallel? Is that right?

[Inverted18650]

The KA3005 looks pretty cool, the current version is P. I'm willing to spend a bit more for something that's useful. What else should I ook at for say $300 US or less? How is the Siglent stuff?

Are your requirements a triple output or could you make do with just a dual?

[Old Printer]

This is a good video on stacking single output power supplies together. Alan is using old HP units, but the principle is the same.

[Inverted18650]

I assume that if I got two separate units, I can't use them in serial or parallel? Is that right?

If they units run on the same freqs (that is to mean the primary DC-DC converter IC's are the same/similar and switch at the same rate), AND they run independent of the other channel(s) on the supply, you can run them in par/series without much concern. Always add the fused link anyway to be sure you down blow the ass out of one of the units or your DUT.

You can do parallel or series up 2 of the 3 channels (in order to double your voltage or current) on the same unit, as long as they are isolated from each other. If you let me know a bit more about what you want/need, I may have something here that fits well within your budget.

Cheers

[skyjumper]

Are your requirements a triple output or could you make do with just a dual?

A dual is just fine.

[skyjumper]

If you let me know a bit more about what you want/need, I may have something here that fits well within your budget.

Thanks!

Variable voltage and current limited. I mostly need something that will let me work on digital circuits, so 3.3V and 5.0V but also I need to power existing equipment that runs as 12V and 24V. As a plus, I would like to have a good bit of current to charge LFP batteries, so 6 to 10 amps total. It does not need to be digitally programmable, knobs are fine as long as when I set it, the displays are reasonably accurate and the knob can be locked so if it gets bumped it does not change. That last bit is not critical, I'm pretty good at not bumping things. Usually!

[Inverted18650]

Hum...thats a bit beast at 10Amps, I do have a coupe HP units that can output 10A per channel but they are a bit more expensive. I may have a very nice, smaller HP unit with fixed 5V and 20V, 5Amp on the 2nd channel...I will check and get back here with pics shortly...

Just a note, one my favorite small multi purpose supplies ( I have 5 of them and a few other in the lineup) is the MingHe D3806, its a PCB style, small footprint, buck/boost converter that you can run from any battery pack laptop brick, etc (any DC input within specs) and get a stable and fairly clean 0-38VDC with 0-6A, adjustable in 1mV and 1mA steps. Also programmable and and has several cool "hidden features".

heres the eBay search, various Chinese sellers, many under $20

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=minghe+d3806&_sacat=0

[Inverted18650]

Sorry mate, but I am at either side of your requirements. I have two HP 6264B which are 20VDC, 20A, and I have a few of the smaller HP 6236B Triple Output units but they are all just 0-6V@2.5A  & +/- 20V @0.5A.  Also posted a pic of one of me MingHe D3806 setups.

[skyjumper]

Thank you for checking!

[skyjumper]

Thanks everyone, I found a used supply on EBay that looks brand new for a great price. I appreciate all the suggestions!