Cheap DC-DC converters for over 60v input.

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fechter   100 GW

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Cheap DC-DC converters for over 60v input.

Post by fechter » Sep 15 2007 11:04am

There don't seem to be many dc-dc converters out there that will handle input voltages higher than 60v. Building one from a "Simple Switcher" chip also limits you to under 60v input.

I had a few switching power supplies that were pulled out from medical equipment in my office, so I tried hooking one up to my bench power supply (actually two bench supplies in series to get enough voltage). At 60vdc input, the thing worked great! It's spec'd to operate from 84 to 240vac input, but since the input goes through a bridge rectifier, dc input works fine. It worked OK on 60v, but crapped out somewhere around 50v, so it won't run off 48v.

The one I tested is
http://www.slpower.com/Upload/Technical ... GSM28G.pdf

I've seen a wide variety of similar switching power supplies at
http://www.allelectronics.com/cgi-bin/c ... plies.html

I think most of the models with a wide input range should work for 60v and above. Many of them are under $10. Perfect for running 10-20w headlights.

Another cool feature is the input and output are completely isolated, so you don't have to worry about getting zapped by the output. You could also possibly connect two in series for a higher output voltage. Since the input goes through a bridge rectifier, you don't have to worry about polarity either. Most of them have very good regulation and overcurrent protection.

Each particular model may behave differently at low input voltage, so some testing would be needed to identify the minumum voltage the thing will actuall work on.
"One test is worth a thousand opinions"

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TylerDurden   100 GW

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Post by TylerDurden » Sep 15 2007 1:50pm

Sweet.

UDM.


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Post by knightmb » Sep 15 2007 2:48pm

That is cool, I'm glad that you found these and tested it to top it off :D

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Fush   100 W

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Post by Fush » Sep 22 2007 7:43am

hey fletcher

Will this work on the plug pack switch-mode's or just the open case ones?
obviously it won't work on all switchmodes but if they do work on at least some of the plugpack ones that would be awesome.

this looks like it will solve a lot of my problems in regards to powering my lighting system. :P

Andrew

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Post by fechter » Sep 22 2007 9:42am

The case style doesn't matter. It does need to be a switcher, though. Behaviour at lower than specified input voltage will vary depending on model, so just try it and see what happens.
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Post by recumbent » Sep 24 2007 3:03am

8) Kewl Man :) I didn,t even know they were called switching power supplies :shock: Ha :P
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dirty_d   10 kW

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Post by dirty_d » Sep 24 2007 7:54am

couldn't you just make a simple buck converter with a 555 timer?

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Fush   100 W

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Post by Fush » Sep 24 2007 8:47am

Hmmm...maybe..but at 72v its gets a bit iffy...

And plus its a lot simpler to run one of these swithmodes...just gut a transformer...hook up your power to the input wires...hook up your outputs and it works.

My setup is almost complete...i haven't tested it on 72v dc to see if it works...i might try that on Saturday when i am at work :P lots of SLA batteries in my shop.

Hope over to my thread if you want to see pics

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fechter   100 GW

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Post by fechter » Sep 24 2007 9:29am

It gets very tricky to make a good buck regulator for 72v with a 555. The idea is to avoid anything that resembles work. Most of us have these things lying around.

A good clue to look for on the switcher is a very wide input voltage range. The ones that go from 100v to 240v are more likely to work.
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Post by fechter » Sep 25 2007 1:39pm

OK, I tested another small switching power supply. It's rated for 1.5 amp, 12v output.

I was able to run a 12v, 20w halogen bulb with the input all the way down to 30vdc! It would run a reduced load all the way down to about 24v input.
I don't think the maximum input voltage of 240v would ever be a limitation on any of my projects.

Forget about dc-dc converters!
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"One test is worth a thousand opinions"

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Post by Fush » Sep 25 2007 5:56pm

fechter wrote:OK, I tested another small switching power supply. It's rated for 1.5 amp, 12v output.

I was able to run a 12v, 20w halogen bulb with the input all the way down to 30vdc! It would run a reduced load all the way down to about 24v input.
I don't think the maximum input voltage of 240v would ever be a limitation on any of my projects.

Forget about dc-dc converters!
awesome mate...i just need to find a SMPS that will do about 1.5amp, my lights and my nokia charger blew my 1amp fuse last night so it means i need to get a bigger power supply...where about did you get yours?
Frame: GT Outpost
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Controller: Crystalyte 72v 40amp
Batteries: 2x 36v LiFEPO4 11amp
Lighting: 2x 5watt Luxeon LED's at 12v (front)
2x 3watt Red Luxeon LED at 12v (Rear)
12v 2amp SMPS running lighting
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Post by TylerDurden » Sep 25 2007 6:13pm

fechter wrote:I was able to run a 12v, 20w halogen bulb with the input all the way down to 30vdc! [/size] It would run a reduced load all the way down to about 24v input.
Forget about dc-dc converters!
Outstanding.

Mass-quantities of LEDs should be a breeze.

:D
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fechter   100 GW

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Post by fechter » Sep 25 2007 9:35pm

Fush wrote:
awesome mate...i just need to find a SMPS that will do about 1.5amp, my lights and my nokia charger blew my 1amp fuse last night so it means i need to get a bigger power supply...where about did you get yours?
Hmm.... it came with a signal generator. I've seen similar models on some of the surplus places. There must be somewhere down there where you can find one. These are common with many computer printers and LCD displays.

Hint: look for ones that have an input range that goes from 100v to 240v.
"One test is worth a thousand opinions"

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Fush   100 W

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Post by Fush » Sep 25 2007 10:14pm

hehe...well since we run 240VAC here it shouldn't be to much of an issue. I have found a few 4amp ones but i am trying to find something compact that i can fit in my box. :P I am pissed that it blew my fuse, but i might do some testing when i get my batts to find out how long it can handle more then 1amp.
Frame: GT Outpost
Motor: Crystalyte X5304 26" Rim
Controller: Crystalyte 72v 40amp
Batteries: 2x 36v LiFEPO4 11amp
Lighting: 2x 5watt Luxeon LED's at 12v (front)
2x 3watt Red Luxeon LED at 12v (Rear)
12v 2amp SMPS running lighting
5v SMPS NOKIA mobile charger
My Ebike Build

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Post by Malcolm » Sep 26 2007 2:35am

Forget about dc-dc converters
Great stuff Fechter!

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Post by Smoker » Sep 28 2007 11:30pm

Pure awesomeness. I would of never thought of it. I tried an ac adapter with 12v 1.5a / 5v 1.5a output connected to my 72v sla output and got the specified outputs. Thanks a bunch!
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Fush   100 W

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Post by Fush » Sep 29 2007 8:43am

Hi all

Here is a video I created while at work today
<embed src="http://www.youtube.com/v/S-uB9f-Rg0Y" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350"></embed>

The SMPS is the same as what I am using in my bike, except I striped the case away.

and yes i know I said hub motor I meant to say hobby motor...I didn't realised that I said that till I got home this evening and watched it...I also just notice that I said 56v, I really wasn't thinking that well when I made this...12x5=60VDC

Edit: ok fixed now
Frame: GT Outpost
Motor: Crystalyte X5304 26" Rim
Controller: Crystalyte 72v 40amp
Batteries: 2x 36v LiFEPO4 11amp
Lighting: 2x 5watt Luxeon LED's at 12v (front)
2x 3watt Red Luxeon LED at 12v (Rear)
12v 2amp SMPS running lighting
5v SMPS NOKIA mobile charger
My Ebike Build

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Post by vanilla ice » Sep 29 2007 12:37pm

I'm never thinking well so no worries there. I'm sure I have one or two of these things kicking around in the garage. Great idea.

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fechter   100 GW

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Post by fechter » Sep 29 2007 4:20pm

Great vid, Fush.

You should try reducing the input voltage one battery at a time to see how low it can go before it loses output.

Small switching mode power supplies used to be quite rare a few years ago, but they seem to be on everything now, which is good for us.

I found several in my garage from old cell phones. 5v would be good for a LED light.
"One test is worth a thousand opinions"

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Fush   100 W

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Post by Fush » Sep 29 2007 7:30pm

fechter wrote:Great vid, Fush.

You should try reducing the input voltage one battery at a time to see how low it can go before it loses output.

Small switching mode power supplies used to be quite rare a few years ago, but they seem to be on everything now, which is good for us.

I found several in my garage from old cell phones. 5v would be good for a LED light.
We managed to get it working down to 48 volts but at that voltage the motor wouldn't start...if we started the motor at 60volts and then quickly change over to 48v the motor would continue running but again it wasn't as effective as 60v.
Frame: GT Outpost
Motor: Crystalyte X5304 26" Rim
Controller: Crystalyte 72v 40amp
Batteries: 2x 36v LiFEPO4 11amp
Lighting: 2x 5watt Luxeon LED's at 12v (front)
2x 3watt Red Luxeon LED at 12v (Rear)
12v 2amp SMPS running lighting
5v SMPS NOKIA mobile charger
My Ebike Build

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fechter   100 GW

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Post by fechter » Sep 29 2007 10:40pm

Good to know, thanks.
"One test is worth a thousand opinions"

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fechter   100 GW

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Re: Cheap DC-DC converters for over 60v input.

Post by fechter » Apr 02 2008 10:03am

Here's one I got from http://www.allelectronics.com/

Part: http://www.allelectronics.com/make-a-st ... Y/-/1.html

Hipro # HP-O2040D43
Input: 100-240Vac
Output: 12Vdc 3.33Amp
Table-top style switching power supply. 5 ft output cord with ferrite bead for EMI suppression. Terminated with 2.5mm coax power plug, center positive. Includes three-prong IEC detachable power cord. UL, CE.
CAT# PS-1233

Your Price: $15.75 each
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I got one of these, and this one fires up at 20v! Pretty close to full output at 24v. Over 24v, no problem.
"One test is worth a thousand opinions"

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"12V" DC-DC converter test results

Post by methods » Sep 09 2008 5:19pm

The topic I wanted to post on is closed: Cheap DC-DC converters for over 60v input.
http://endless-sphere.com/forums/viewto ... =16&t=2264

I spent a bunch of time making a post so I have got to put it somewhere. . . :roll:


TEST: Toshiba Notebook brick

MODEL: ADP-60RH A (V85)
SIZE: 4.5” x 1.5” x 1”

INPUT: 100 – 240V AC
OUTPUT: 15V 4A DC

*note: Most car alternators keep your battery voltage at somewhere around 14.4V or 14.8V so whenever selecting a “12V power supply” always try to shoot for a 15V unit. That will allow you to make more power for less current (smaller package).

**note: Bricks do not need to say “switching power supply” and in fact most don’t. Simply look for units that don’t look like they have a big heavy transformer inside. Nearly any laptop power supply will meet this criteria.

TEST DC INPUT: 100V, 50V, 36V
TEST LOAD: 4ohm 1% resistor (5.3ohms “hot”)


TEST 1) 100V input

No load input voltage: 100V
No load input current: 4ma
No load output voltage: 15.32V
No load output current: 0A

Loaded input voltage: 100V
Loaded input current: 642ma
Loaded output voltage: 14.5V
Loaded output current: 3.533A

Reality check:
Calculated load: 14.5/0.642 = 4.104 ohms (cold)
Actual load: 4ohms

No load input power: 100V * 4ma = 400mw
Loaded input power: 100V * 642ma = 64W


TEST 2) 50V

No load input voltage: 50V
No load input current: 4.5ma

Loaded input voltage: 50V
Loaded input current: 1.423A
Loaded output voltage: 14.5V

No load input power: 50V * 4.5ma = 225mw
Loaded input power: 50V * 1.423A = 71.15W

**note: Output current was not monitored
**note: Load was heating up so resistance ranged from 4ohms to 6ohms


TEST 3) 36V

No load input voltage: 36V
No load input current: 7ma

Loaded input voltage: 36V
Loaded input current: 1.57A
Loaded output voltage: 12.5V

No load input power: 36V * 4.5ma = 162mw
Loaded input power: 36V * 1.57A = 56.52W

**note: Output current was not monitored
**note: Load was heating up so resistance ranged from 4ohms to 6ohms


I have several others. The one I plan to use is 15V @ 5A
These are nice, clean, tight little packages. No soldering, water resistant, pre wired, slam dunk.

Thanks
Thanks
Thanks
Thanks
Thanks to Fechter for bringing this to our attention.

I just bought a Kelly that needs 12V – 24V and this will be the hot ticket. I am going to rig up a cig lighter too so that I can charge my cell phone etc. Maybe even a 110V converter so I can blow-dry my hair or charge my electric tooth brush.

-methods
Increasing battery voltage and controller current limit will result in a non linear experience

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