Hi folks,

I'm new here, so please be gentle !

I'm currently working on a project ........ designing my own quad headlight system. I'm at the planning stage for the headlight upgrade wiring loom.
What I'm after is a benchtop power supply for testing my headlights and wiring looms. And various other projects I have in the pipeline. I've spent an awful lot of time looking at benchtop power supplies, but the only ones I can find are a maximum of 10amps.

What I really need is a variable voltage and current benchtop power supply, capable of supplying 0 - 20 volts DC with at least 30 Amp max.

Why have all my searches only been up to 10 and 15 amp max ? surely up to 30 Amp must be available.

Anyone know where I could buy one, or even recommend one ?


TURK_UK

 

You could use a lead-acid battery to get the high current and just charge it with a low current charger.

Why do you want a varying voltage?

A 0-20V, 30A supply will not be cheap.

 

XG 20-42 http://www.programmablepower.com/dc-power-supply/XG/Specifications.htm

but you won't like the price.

Some "Identical" supples can be operated in what's called series and parallel operation. There are external interconnects that would double the voltage or double the current. They operate in a master/slave arrangement usually.

 

Thanks for the quick response Crutschow.

I'm working on a testing lab, workshop for building custom made headlights. I really need a better set up than my existing battery set up I currently have now, like you suggest. I also went down the ATX power supply setup very early on in my project ........ I think it's now time I approached my project with a more professional setup.

I realise it's not going to be cheap, but they are difficult to find for some unknown reason. Probably quite a specialist thing actually. But I'm prepared to pay good money for the right unit.

I just found on Google some VOLTEQ 30V 30A regulated power supplies ....... any good ?
Around 300 bucks ....... or 300 Euro as I'm in France !

TURK_UK

 

XG 20-42 http://www.programmablepower.com/dc-power-supply/XG/Specifications.htm

but you won't like the price.

Some "Identical" supples can be operated in what's called series and parallel operation. There are external interconnects that would double the voltage or double the current. They operate in a master/slave arrangement usually.

Yeah, you're right ................ I don't like the price !!!

A third of that price would be good. Is what I'm doing possible with a smaller budget I wonder.

Designing and fabricating a custom quad headlight system is expensive as it is, but the prices of my tooling must be within reason.
These will be top quality headlight systems, I'm going to test each and every system before they leave my workshop, custom wiring looms also ........ so my test equipment must be up to the job, and reliable. Am I asking too much ?



TURK_UK

 

a Power supply going down to zero volts adds a challenge for heat dissipation. It is actually more difficult to deliver full current at the lower voltages while delivering full current. All that heat must go somewhere or a switch mode supply is needed.

I would look at putting two good ATX power supplies together in series.
12 +12v gives 24v,
12+5 = 17 and 12+3.3 =15.3
12,
5+5=10
3.3+5 =8.3
3.3 + 3.3= 6.6
5
3.3

Just disconnect the chassis ground from on supply before starting.

Cheers.
(Bon Jour)

 

That looks a little complicated for me GopherT ..........

Not to mention I would have to invest in a couple decent ATX power supplies. Got some old ones knocking about the place, mostly in pieces !
Heat dissipation I don't think is going to be an issue at zero level voltages, as it's mostly going to be run at 14.4 volts as to emulate the car battery when engine running. At least that's the theory.

Something like this I think > http://uk.rs-online.com/web/p/bench-power-supplies/4938000/

Quick figures ............... 4 x 65 watt lamps ........ averaged 5 amps per lamp = 20 amps should suffice ?


BTW............ Merci GopherT !



TURK_UK

 

How about this?

 

How about this?

Ouch !

Bit pricey, but if that's the sort of thing to get the job done so be it. That's certainly got a lot of potential, I'll download the tech sheet on that one and go through it.

Many thanks Crutschow



TURK_UK

 

The VOLTEQ 30V 30A supply may work for you.
It has a one year warranty but, of course, there's always the concern about the long term reliability of an unknown Chinese brand device.

 

This http://literature.cdn.keysight.com/litweb/pdf/5952-4020.pdf handbook is old, but it was a bible to me back in the day. I bought a fair number of 1500 W power supplies in close to the range your working in. I inherited maintaining a bunch of Sorenson DCR 300-6 or 300 V @ 6A and 150-3 At about the 7 or 10 year mark, I just had to "blanket replace" a few electrolytic caps. The other supplies were Xantrex and Kikisui in the 1500 W range. The Kik's had no issues in 20+ years.

Back in the 80's, I bought a Harrison labs power supply (Bought by HP) for like $15.00 USD. It was poorly repaired, but I got it working and it's still working. It wasn't until a few years ago that I got the schematic. It called itself a Fixed Voltage Power Supply, selectable between 0 and 32 V, 10 Amps. That was my 12 V automotive supply for fixing car radios.

A Lamda PS gave us no troubles either.

Now, the 0-100kV at 0.1 A and the 10-15 kV at 1.5A gave my predecessors problems. Once I really fixed them, they were fixed; instead of breaking every year or so.

Look at the handbook and then the used market.

This https://www.circuitspecialists.com/array-3720a-dc-electronic-load.html might work for you.

 

I don't get it. Why not use one of those things they keep in auto shops for jump starting cars? Big battery plus high-current charger. You don't need variable voltage or current, don't pay for those niceties. You just need reliable.

 

You might also consider one of these used Agilent 20V, 20A supplies.
They are generally pretty bullet-proof.

 

I don't get it. Why not use one of those things they keep in auto shops for jump starting cars? Big battery plus high-current charger. You don't need variable voltage or current, don't pay for those niceties. You just need reliable.

You don't 'get it' because you're looking at it from your point of view wayneh ................ look at it from my perspective. I already mentioned earlier in the thread, I've done the ATX power supply route, the car battery on it's own to power 12 volts devices, and the 12v battery connected via a battery charger to give the necessary 14.4 volt required ....... done all of that for the past few years. As with all guys, I'm a tinkerer ! ........ I have Ardiuno, Raspberry Pi and loads of other electronics projects, so it makes sense in buying a variable power source.
My quad headlight project and testing the wiring looms that will power all four headlight units ON in high beam, is the most I'll be using the power supply for. So a measly 3amp, 5amp or even 10 amp power supply just won't cut it. It needs to be a very least 20 amps.

But it's also time I looked at my setup, so I need to buy the proper tools for the job. I have many orders for these custom headlights to fulfil, so each and every set will be tested before leaving my workshop.

I've also dispensed with building my own out of PC supplies, I'd have to learn electronics before I even attempt that. I need to buy something ready made, not used as I've also dispensed with that. There's usually a pretty good reason why somebody would part with an old regulated DC power supply ! They invest in a new model, and you're lumbered with their old model that usually doesn't work or is unreliable !

I've researched in the last few days literally hundreds of different models, I'm reluctant to buying one in France, first of all, choice is very limited, and that sort of equipment is outrageously expensive over here. I can't buy one in the good old US of A ........ the shipping and carriage would equal the price of the unit alone ! So I'm left with buying one in the UK. Anyone from the UK here ?

Best option I have found so far is > https://www.rapidonline.com/voltcraft-sps-1525-pfc-375w-single-output-dc-power-supply-51-7492

At £111 ( that's about a 100 bucks to you guys ) it's respectable.


One thing I keep on coming across is, 'Linear' or 'Switching' power supplies ........ which should I concentrate on ? Most important for me is, powering four 65watt bulbs via relays, hence the 20+ amps.

At this point I would just like to mention that you've all been very helpful, and many thanks for your suggestions, I feel I'm getting somewhere now. Understanding how this is going to work is another matter !


Talk to you soon guys.


TURK_UK ( in a little village in the middle of nowhere in central France )

 

One thing I keep on coming across is, 'Linear' or 'Switching' power supplies ........ which should I concentrate on ?

Advantages
Switching power supplies are lighter and more efficient.

Disadvantages
Higher ripple (usually)
More complex

I've seen the effects of both vibration and ripple on incandescent light sources. The spectrum of the light is even influenced by brand. Uniformity was tough too. Spectrum is influenced by voltage.

 

As with all guys, I'm a tinkerer ! ........ I have Ardiuno, Raspberry Pi and loads of other electronics projects, so it makes sense in buying a variable power source.

OK, I get it. Personally, I'd still look for a separate solution from the 20A project for all those other projects. With all the tinkering I've done, I don't think I've ever used more than 2-5A on my bench and it's only rarely more than 0.5A.

 

With all the tinkering I've done, I don't think I've ever used more than 2-5A on my bench and it's only rarely more than 0.5A.

Lately, most of my breadboarding has been done on an old Heathkit ET-3100 because it combines a breadboard, dual polarity adjustable supplies, a 200-20kHz frequency generator, and a 30VAC center tapped transformer.

The power supplies are zener (!) regulated and current limit at around 150mA.

Can't remember the last time I needed to use my 0-30V 0-3A digital power supply or it's analog sibling. I usually just grab a wall wart with the appropriate (fixed) voltage.

 

Youse guys don't get it. This TS is testing automotive components. He needs at least 15V 30-50A.

I have built testers for flashers and windshield wiper relays. You need to have wiring and interconnects in the sub-milliohm range.

What the TS is looking for is a low cost solution. I think he is going to have a hard time finding it.

 

What the TS is looking for is a low cost solution. I think he is going to have a hard time finding it.

I disagree. He already uses an auto battery/charger arrangement and I contend that is already the superior (lowest cost) solution for this application. I think it could get an upgrade to higher power, put it on a cart with wheels, whatever makes it more reliable and convenient. The TS wants variable voltage and current for other purposes. While he wants one device to suit all his needs, I've given him my opinion that I wouldn't attempt to do it all with one power supply. I charge my car batteries with a battery charger, not my bench power supply. I wouldn't try to merge them into one multi-purpose supply.

The TS is free to reject my opinion for whatever reason. The best I can do is offer it.

 

Hi guys,

Many thanks for those last few posts ............... I'm inclined to agree, with respect to the 'one use' method. Trying to put all my eggs in one basket ( using only one variable benchtop power supply for all my projects ), now doesn't seem to be such a good idea. Smaller power supplies ( 3v - 5v and the like that also read milli-amps ) are very cheap, I'll just have to buy one of those at a later date for Ardiuno projects. From what I've recently seen on the net, there's litterally hundreds of em to choose from !

I'm finally narrowing down a unit that may just foot the bill, what are your opinions on this model '
Voltcraft SPS 1525 PFC 375W Single Output DC Power Supply'
> https://www.rapidonline.com/voltcraft-sps-1525-pfc-375w-single-output-dc-power-supply-51-7492

With a voltage setting range from 3v to 15v that would cover 14.4 volts that a car battery delivers when idling. But it states 'Fixed current limit: 25A', would that mean it goes upto 25amp continuous ? Hopefully I can adjust that accordingly.

One of the options that I'm fabricating will operate four independent hight beams, so four H1 bulbs @65watts each
So that would be about 4.5Amps x 4 totalling about 18Amps

I did want to go a little higher in amperage as it's always nice to have a little in reserve. Hence wanting at least a 30Amp variable power supply.

It's been mentioned that I'm going to have a hard time finding what I'm looking for ............... you couldn't of spoken a truer word I can't understand why this would be so difficult ! It's just a high amperage transformer at the end of the day. That model I've linked to isn't too expensive either, and as I'm prepared to spend a little more, what extra features would I need, or that you would recommend me looking for ?


TURK_UK