DC Power supply anyone?

[Philldpapill]

I'm sick and tired of using my battery bank and battery charge in my "lab"(garage). So, I'm going to finally put my EE know-how to use on this and stop using the "ghetto" setup I have. I'm going to build a high power DC Power Supply.

What it will consist of, is a high power switch mode power supply that runs off the 120VAC(house plug). It's going to convert this 120VAC to an adjustable voltage output between 0V and maybe whatever... maybe up to 100V. No bulky transformers or anything. Here are some preliminary specs:

Output Voltage: 0V - 100VDC (?) --Variable-- Update: 100V @ < 10A
Output Current: 0A - 50A (?) (50A @ 20V, 10A @ 100V - 1kW total power output)
Input Voltage: 120VAC - 240VAC
Input Current: ~10A
Switching Freq.: To be determined(~30kHz?)

Anyway, when I build something for myself, I typically like to build a couple more to sell off or give to a friend since it's usually cheaper to by more than qty 1 of the parts.


Would anyone be interested in one of these? Price would be ~$150 (Updated: was ~$50 or $60) I think. This is going to be a very stable supply of power for your HHO cell. AND it's adjustable so you can find just the right voltage drop per cell...

[Roland Jacques]

Yes, I'm very interested. PM sent
The low voltage could allow me to do some experiment with far less expense

[keiththevp]

Any idea how much it will cost? Not that it matters since it is much easier then running a vehicle for hours on end to do bench tests. But as long as it is reasonable I am in.

[Philldpapill]

Great! This project isn't something that will be done next weekend... I'm just starting the design phase, and probably won't be done for a month or so.

Remember, this is a benchtop power supply that uses AC as the input - NOT something you mount in a vehicle. I'm going to use this for experiments and testing my cell.

EDIT: Keiththevp, you beat my post by a minute... The price range is probably around $50-$60. My commercial 20A unit was $250, but it's precise and extremely stable. This unit is more of a raw power, without a large amount of noise reduction... But then again, who cares about a small bit of EMI going through your HHO cell?(Perfectly safe... electronics being POWERED by such a power supply may not usually like it too much, but HHO cells aren't really electronics)

[Roland Jacques]

Phil what do you think about a volt and amp meter built in.:D:D:D
That would be worth an extra $30-$40 bucks IMO.

[Philldpapill]

Sure... It might be a digital readout like on one of those 2 line, 20 character LCD screens though. Or if you really want an analog meter, I can do that.

[Bayesoft]

I have designed a new type of hho dry cell with a plate configuration that I have not seen used, mentioned or tested anywhere else. Theoretically it's a perfectly sound design, but I can't speculate on it's performance until it's up and running.

A variable DC power supply would go a long way to determine precisely how it behaves under a given set of parameters. Much testing will be needed before I can share my results.

I would be very interested in seeing your work. I will be purchasing my components at the end of this month.

Thanks,

[Philldpapill]

Yeah, that's what I was thinking, Bayesoft. With an adjustable supply, you can compare the MMW at different voltages... Generally, the MMW increases at lower votlages/lower current densities. I'd really like to make some plots of voltage per cell, vs. MMW. I have a feeling it would be a decaying "f(x) = 1/x" type function.

I was developing an all-in-one AC powered system that could interface to your computer to display/log/change data. It can measure airflow, power, energy used, etc. etc. etc., so that you can do expirements fairly easily. However, there wasn't much interest in it, so it's on the back burner. This Power Supply also seems to have gotten very little interest(except for you guys!), but I'm primarily building it for myself, so this WILL get done soon.

Anything else you guys want on this? So far, the only extra is a voltage/current meter.

[Philldpapill]

If you guys want to make a cheapy variable voltage supply out of your existing PWM(run off 12VDC or your battery), you can adjust the frequency of your PWM to at least 20kHz, and then add a few capacitors in parallel with your load. Here is a good one that should work for anything below 35VDC: http://mouser.com/ProductDetail/Vishay-Sprague/36DE103G040AM2A/?qs=sGAEpiMZZMtjXoiUFBEm5bLdyQcUj1pjM%2fzDhC1WShs% 3d

Generally, you'll probably want at least 1,000uF per Amp. These are 10,000uF, so each one should be good for 10A. Just add multiples for however many amps you are pushing. Doing this alone should increase your efficiency somewhat, and cut down on heat. Enjoy.

[methaneb]

I've been dying to find a good benchtop power supply for under $100 (which is probably a self-contradicting statement). I've had bad luck converting ATX power supplies, and all of the DC 12V ones around here only handle up to 3 amps. I would definately be interested in something like this.

[IM2L844]

I'll buy one for sure. I think I paid nearly $300 for my Astron VS-70M, but it's pretty sweet and I hate using it to power my electrolyzer.

[Stevo]

I would like one as well. Let us know when they are available.

[rcflyn]

Count me in on this project also..
My Old Volvo battery and Battery Charger sure are getting TIRED....
Let us know when you are getting close Phil.
I'm INTERESTED...

[Helz_McFugly]

hurry the F up Phill. Using a battery charger for testing is getting old, and its just not accurate. :rolleyes:
you take you time as if you have a job or something. we all know you just sit at home and smoke your home made water bong, listen to reggae music, and eat cheetos alllll daaayyy loooonnnggg

[Roland Jacques]

hurry the F up Phill. Using a battery charger for testing is getting old, and its just not accurate. :rolleyes:
you take you time as if you have a job or something. we all know you just sit at home and smoke your home made water bong, listen to reggae music, and eat cheetos alllll daaayyy loooonnnggg
YEAH, what he said!

[Philldpapill]

They aren't cheeto's. It's either trail mix or honey buns. Best munchie food ever.

As for the project... I'm waiting on some new high-voltage MOSFETs to come in. The slightest little screw up, and these things instantly smoke out my shop. The trail mix and honey buns are broken out immediately thereafter. LOL

Another big draw back is related to my "Hulk" PWM. Since these two devices are closely related, the bug in my PWM also applies to the DC Power Supply... So, until I get THAT worked out, the DC Power Supply isn't taking off... I'll post updates here a bit more often from now on.

[HHO BLASTER]

I have a ton of transformers from microwave ovens if you remove the secondary you can wind your own with #8 wire and two 100 amps diodes throw a filter cap on, to vary the voltage use a light dimmer in the primary or use a second transformer and then put it's secondary in series with the primary of the other one and it will act as a bucking transformer to vary the voltage

If you want one let me know and i will send one for free, just pay the postage

if you don't know how to do it just ask

Using a transformer will isolate you from the AC power

Gary

[Philldpapill]

Ok, bad news... You guys have influenced me to start working on this PS a more. I've been running some simulations and it's not that pretty...

1) It's looking like the power rating of this thing is going to be lower than I had hoped. Probably about 1kW... Maybe less.
Reason: Multiple - The capacitor needed for LARGE loads is ridiculously expensive. Just looking at Mouser.com, the very minimum I would need for 1kW is already $14, and I'll probably end up needing two of them. That doesn't sound like THAT much, but parts add up VERY quickly. The second reason is the MOSFETs. I just so happen to have a bunch of high voltage fets, but I don't think they can handle the needed current. The alternative ones are about $6 a pop and I'd need at least 4. Heat dissipation might be an issue, too...

2) At large currents, the ripple voltage/current that the load sees is going to be a little nasty. From my rough estimates, it could possibly be as bad as 25% at 120Hz. Ouch.
Reason: Again, it goes back to the expensive capacitors. The "ripple" is where the voltage/current starts to sag as the input voltage sags(following the sine wave AC power input). I might be able to add some software power factor correction that would continuously adjust the duty cycle in order to keep the output fairly stable. I'm hoping I can use this to reduce the ripple to 5%.

3) You aren't going to be able to supply 100V at Maximum current. Hopefully 10A @ 100V(1kW).
Reason: That's an a$$-load of power to begin with! Stop being greedy. Actually, it's due to that dam capacitor again.

Bottom line, if you guys want to pay $50-$75 MORE, I might be able to bump the power up a bit. BUT that's not for sure. Right now, the price is looking more like $150 for the unit. I'll update the first "Specification" post in a bit...

[Helz_McFugly]

I cant speak for anyone but myself when I say " I dont want a cheap one, I want a good one that works, I dont mind paying more for it. I really need a good PS that is adjustable for testing this Urea project." PM sent.

[HHO BLASTER]

Here is another way to make a high current DC SUPPLY FROM FREE CRAP

Find two big old tread mills, treads use DC permanent magnet motors which

when hooked backwards become DC GENERATORS

You can use one treadmill motor and the controls to drive the motor speed then

using the belts and pulleys THAT COME WITH THE FREE TREADMILL to DRIVE THE SECOND DC MOTOR WHICH BECOMES A

DC GENERATOR IF YOU HAVE A BIG ASS MOTOR YOU WILL HAVE A BIG ASS DC

GENERATOR YOU CAN THROW A LARGE FILTER CAP ACROSS IT BUT DON'T

FORGET THE CAR BATTERY ACT'S LIKE A BIG CAP AND SO DOES YOUR HHO

SET UP SO IF YOU WANT TO RAISE THE VOLTAGE RAISE THE FIRST TREAD

MILL MOTOR SPEED

TREADMILL MOTORS ARE NOW BEEN USED AS DC WINDMILL GENERATORS THE

DC IS USED TO CHARGE BATTERIES IN OLD UPS SUPPLIES TO CONVERT BACK TO AC POWER

[Philldpapill]

Well, I take back half of what I said... The output current is BACK up to 50A at lower voltages(<20V). The power that can be delivered is still around 1kW, so don't expect 50A at 100V. However, this SHOULD be able to supply 50A to a regular 13.8V HHO cell with minimal ripple voltages/currents. I'm going with two of these 1.8mF capacitors, so just the capacitors will be $26 alone. Price is still looking to be ~$150. Around the same as my DC "Hulk" unit since they are virtually the same technology.

I rarely say this about anything I build, but I just want it to be absolutely clear... This is a "USE AT YOUR OWN RISK" device. I won't put this out there without having my own confidence in it, but you are very capable of doing something rather stupid and hurting yourself... If you happen to DIE while tinkering this, don't come knocking at my door with a lawsuit. As long as you use it correctly, there shouldn't be any problems.

[Helz_McFugly]

If your PS kills me Im going tobe very ****es off