Author Topic: High quality "bench top" power supply for 12V electrical system?  (Read 2311 times)

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Offline Lomax

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High quality "bench top" power supply for 12V electrical system?
« on: December 09, 2017, 12:43:40 am »
Hi all,

I need to get a dual (or two linkable) power supply for the "lab" on my boat. I've been looking at the RD Tech buck/boost power supplies for a while - these seem quite popular but I'm put off by a few things. Most significantly, due to being (cheap) switched mode PSUs they seem to be rather noisy; I've seen 50mV ripple in some YT test videos, which is pretty bad. I am also unimpressed by the clunky user interface and tacky display unit, and I always prefer fanless designs when possible. I currently have a hefty linear Thurlby Thandar dual supply, which I'm quite fond of, with its dedicated knobs and displays for current/voltage, but it is far too large and power hungry for use on the boat. Using a 240V unit would also necessitate running the inverter, only so that the PSU can then convert this to (typically) 5 or 12 VDC, which seems a bit crazy. So I thought I'd ask here; does anyone know of a high quality bench top power supply with dedicated controls which can run off 12 VDC and provide (minimum) 30V / 3A? Or are the RD Tech ones as good as it gets? I'd happily pay quite a lot more than what the RD Tech units cost!
 

Offline Lomax

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #1 on: December 11, 2017, 02:26:12 pm »
Oh my, that looks so much better! https://johan.kanflo.com/opendps-design/

 

Offline ChrisLX200

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #2 on: December 11, 2017, 03:16:17 pm »
Oh my, that looks so much better! https://johan.kanflo.com/opendps-design/



It doesn't look better to me... you lose readout info on what the settings are? Still, everyone has their own idea of what works...
 
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Offline Lomax

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #3 on: December 11, 2017, 04:31:58 pm »
everyone has their own idea of what works...

Agreed. I'm used to a bench PSU which shows only three bits of information per channel: actual output voltage, actual current draw, and whether current limiting is active. This works well for me. I am also quite fond of having separate knobs for voltage and current. The DPS/DPH UI by comparison looks like someone's puked all over the display after eating a spreadsheet, and having read the manual I'm thinking they probably had a few drinks too. :palm:
 

Offline Lomax

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #4 on: December 12, 2017, 12:53:23 pm »
From the lack of alternative suggestions, I assume there are no real alternatives to the RD Tech DPH5005. Looks like I'll be placing my first ever order from Aliexpress then!  :o
 

Offline glarsson

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #5 on: December 12, 2017, 01:02:45 pm »
If you need two of them and connect both to the same 12V supply then you must be aware that these power supplies does current sensing on the negative outputs. This means that if you connect both power supplies to a common 0V (e.g. for +5V and +12V) then the common ground on the input (the boat) and common output (the device under test) will short out the current detection of the RD Tech units. These units really needs separate power sources...
 
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Offline Lomax

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #6 on: December 12, 2017, 05:20:43 pm »
If you need two of them and connect both to the same 12V supply then you must be aware that these power supplies does current sensing on the negative outputs. This means that if you connect both power supplies to a common 0V (e.g. for +5V and +12V) then the common ground on the input (the boat) and common output (the device under test) will short out the current detection of the RD Tech units. These units really needs separate power sources...

Ah. That's a very good point, thank you! So the outups are not "floating" or "isolated" then? Hmm. I guess that means connecting two of them in series to get a symmetric supply (e.g. for audio amplifiers) is also out of the question :( What to do? Use a regular 240V PSU via an inverter?
« Last Edit: December 12, 2017, 05:22:53 pm by Lomax »
 

Offline paulca

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #7 on: January 19, 2018, 11:14:15 pm »
Quick question.  If both supplies are running off battery, is it safe to common ground them in a circuit?
"What could possibly go wrong?"
Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 

Offline james_s

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #8 on: February 02, 2018, 02:17:16 am »
My favorite 12V power supplies are any number of hot swappable server PSUs that are all over ebay for peanuts. You can get 12V at 30-80 Amps for typically not much more than the cost of shipping. With a little work most of them can be modified to run in series, I have a series pair set up as a 1400W 24V PSU for my LiPo chargers.
 

Offline Lomax

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #9 on: February 06, 2018, 01:17:55 pm »
My favorite 12V power supplies are any number of hot swappable server PSUs that are all over ebay for peanuts.

You got this the wrong way around; I'm looking for a current limiting "bench" PSU which can provide ~0-30V DC from a 12V DC source.
 

Offline paulca

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #10 on: February 06, 2018, 01:43:52 pm »
You got this the wrong way around; I'm looking for a current limiting "bench" PSU which can provide ~0-30V DC from a 12V DC source.

I got my DPH5005 and put it into service last week.  Works fine.

I prefer BangGood as they accept paypal.  Aliexpress has a habbit of greying out Paypal. Putting my debit card details into a (likely) Chinese website makes me uncomfortable.
"What could possibly go wrong?"
Current Open Projects:  3 Channel Audio mixer with DAC, BT, pre-amps and h/phone amp, WS281x LED controller Version 2 5V/5A w/Atmega328, FY6600 Power supply, 5A DC Load (Still!)
 

Offline ironcurtain

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #11 on: February 06, 2018, 03:43:46 pm »
OpenDPS is still very, very early stages. No PID loop, no support for the 50v versions in terms of precise display/metering.... If you flash it it's a one way street without a dump of the original FW.
 

Offline bob808

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Re: High quality "bench top" power supply for 12V electrical system?
« Reply #12 on: September 16, 2018, 10:22:30 pm »
Got a DPH5005. Any chance on adding a sense line? Anyone has the schematics for these power supplies?
 


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