high amp 12v Power Supply

[DrPinky]

I was thinking. In my work area I use lots of 12V stuff like my homemade security system, rotating red lights(about 4 of them ), and lots of lights. I was wandering would it make sense to get a welder and use that as a power supply? The welder outputs around 24V and is capable of delivering 300 amps. Is there anything wrong with this? I would have to step down from 24V to 12V but that shouldn't be a problem. Am I crazy, I wont blow myself or my stuff up will I???? I figured I would ask before I tried it.

 

[OLIVE2222]

Hi Dr Pinky,

I guess that a welder supply have maybe a less "clean" output then a lab power supply, should be OK however for rotating lights when passed through the 24/12v converter, to be checked for the alarm system. Other unknown thinks (to me) is how the regulation will behave with such small loads. Also the regulation is probably optimized for fast load transition.

Olivier

 

[davenn]

I personally wouldnt consider it.

no current limit ability .... you are going to let the smoke out of projects often

no regulation / smoothing ... thats not going to go well with much sensitive electronics

A decent lab supply has both those features along with Voltage and current meters to see exactly where you are
Nothing you ever do in your workshop is going to require 300A. and you are not going to rectify and regulate that sort of current with anything easily purchased off the shelf.

for the avg workshop 10 - 15 is morwe than enough, even 5 - 10A plenty

Dave

 

[davelectronic]

Welder modded power supply

I have got to agree what could you possibly need with 300 amps, why not build a bench supply, loads of schematics on line, i am power mad, i want to attempt a high current modded micro wave oven transformer as the base, but would not run sensitive electronic circuits on it, for me and power thats the limit, unless another better transformer comes along ie performance parameters.

Ive often wandered about the welder idea, but its a step to far for me, and i dont need to power the town where i live, lol.
Dave.

 

[Resqueline]

Nothing wrong with supplying a 0-30V 0-10A (or whatever) electronic regulator circuit with a 24V 300A transformer. Just put a 15A fuse in series for safety's sake.
With 32V rectified and smoothed DC in and 12V out a linear regulator will dissipate 20W for every Amp drawn from the output though.. Did I hear fan cooling?

 

[duke37]

I wouln't use a welding transformer since they are made with a high leakage inductance, normally adjusted with a wheel at the end. The inductance drops the voltage as the current rises, and more seriously, gives a voltage spike when the current is reduced.

The rating of a welding transformer is based on intermittent use so the output will be much less when used continuously.

 

[DrPinky]

Thanks everyone for the advice,
I think I will try it with some lights I don't care about first (I will use fuses ). I already have a good 10 Amp lab power supply with two analog gauges (one for volts and one for amps) which currently powers my security system and 3 of my rotating lights that take 2 amps apiece and my 4th light which is orange takes 10 amps at 24v(its currently powered by a battery charger). I agree with everyone I probably shouldn't put sensitive stuff on it without serious regulation. I don't plan on using 300 amps or anything close to that we just have a couple of cheap welders laying around and thought maybe cheaper than buying/building more power supply's.

(here are my lights )