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Old Jan 29, 2012, 12:04 PM
Use the 4S Luke
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USA, TX, Euless
Joined Aug 2003
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I think that the limit has been reached (~1,000W) because of the voltage and current available in household circuits. You can build a 2,000W or 4,000W charger but how is the ordinary going to power it? I can easily charge packs for my 50cc planes now. The market for planes >50cc is pretty limited compared to 50cc and below.
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Old Jan 29, 2012, 07:25 PM
Power! Power! Power!
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Joined Jan 2012
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Quote:
Originally Posted by earlwb View Post
Wow that is a really cool power supply, 48v at 2300 watts or thereabouts. Awesome.
Right now I do not think that anyone has manufactured a 48 volt input Lipo charger yet. But at the rate things are progressing, a charger like that is just around the corner, so to speak. There are some Lipo chargers that are setup to handle 36v input for up to 14 lipo cells.
There might be some LiFe chargers that can use that, like for the car battery packs and maybe some old style lead acid PB chargers like used in golf carts, etc. I see the Chinese on Alibaba show a lot of 48v chargers for things like electric bicycles and such too.
Some guys are now running 15 cell Lipo packs for really big airplanes and such too. So there is a really small market for it at this time.
Some one was discussing it here at one time http://endless-sphere.com/forums/vie...p?f=14&t=22881 it looks like they applied 48v in to a array of single cell Lipo or LiFe charge modules built onto a set of PCBs.
Ah, interesting info and link, thanks earlwb. BTW, this PSU is 18,000 watts.
2 banks of isolated 9,000 watts each, fed by 3x 3,000 PSUs per bank!

Since computer power supplies are designed with primarily resistive loads, it probably wouldn't run any motors or such directly - however it might be good to use for a home-made uninterruptible power supply with forklift batteries!

Someone here mentioned the possibility of opening them up and "underclocking" them to a lower voltage instead of pushing them up higher. Wonder If I could get them down to 36v...
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Old Jan 29, 2012, 07:39 PM
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USA, TX, Grapevine
Joined Dec 2008
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My mistake I missed the 9000 w statement further on. That does put your PSU in the over the top category for power supplies.
When I ride my bicycle to work and back, I used to pass a business that had a old electric forklift in the back. It had something that looked like six banks of lead acid batteries in trays mounted in it. So I guess that monster PSU would work for something like that.
I guess you could go for a full size electric airplane, but I don't know about the flight time though.
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Old Jan 30, 2012, 03:01 PM
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Bundesrepublik Deutschland, Berlin, Berlin
Joined Feb 2011
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DPS-700eb

I turned off the OVP in my DPS-700EB Power Supply. (post844, xandrios). This works well so far (14 to 14.8 V). But the output voltage varies depending on load very much. That's why I wanted to "return sens" pin8 with the link to the output voltage. Now I'm not sure I've found the right pin. The output voltage should fluctuate less load dependent.

What do the five sliders on the daughter board? I guess three pots to take control of three output voltages (5Vsb, 15Vcc, +12 V). The other two pots are probably responsible for the OCP (5Vsb, +12 V). The one has ever tested exactly?
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Old Jan 30, 2012, 03:26 PM
Steven
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United States, CT, East Hartford
Joined May 2010
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Hello s.nase,

I've fully tested this mod at 15.0v with a 65A load.

The output voltage did not drop even at full load.

Did you test the output voltage at the PSU??

And how is your potentiometer wired?

Make sure that the two main ground outputs are connected together. Top and bottom.

And make sure the two main +V outputs are connected together. Top and bottom.

This might make the difference.

Also, potentiometer(slider) #5 adjusts voltage. Counterclockwise to increase.
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Old Jan 30, 2012, 06:14 PM
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I measure my output voltage directly at the power supply.

My cabling makes no difference on the low side of the potentiometer (1k/2W).

Without a load at the output, I can adjust stable voltages from 14V to 14.8V. At higher voltages the power supply comes out of the stroke. Exactly at 15.5V it works stable again. When I load the power supply with 20A, the voltage drops by 0.2V.

You are changing the voltage of the internal potentiometer on the daughter board, or on the external potentiometer at PIN63?

Which function has and PIN1 PIN8?

Have you found a way to control the fan speed depending on load? I would also replace the four small fans (two PSUs in series) against a large 80mm fan. The tachometer signal is to be distributed via a opto-couplers.

I like the DPS-700EB extremely well especially because you have to get disabled the OVP. Is there a trick to bridge the OVP in other power supplies?
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Old Jan 31, 2012, 07:42 AM
Steven
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United States, CT, East Hartford
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Hey s.nase,

I think that I have a solution for you. I will post later today.
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Old Jan 31, 2012, 02:28 PM
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I was not careful enough, I toasted the PIC in one of my DPS 700EB. But I'm still enough other 700EB. Maybe I can copy the software to a new PIC. I have the wrong contact in the picture in my last message already corrected.

Before my misfortune I've played a bit with the pot5. I've found a setting in which the output voltage remained stable. But once I've set more than 14.8V, the PSU came back out of the stroke.

Let's see what my other 700EB.
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Old Jan 31, 2012, 04:02 PM
Steven
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United States, CT, East Hartford
Joined May 2010
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Hello s.nase,

sorry you fried the PIC.

It can easily happen with a slip of the fingers.

I've discovered that the OVP mod for the DPS-700EB seems

to work slightly different on each unit.

On some you can reach 15.2v. On others you can only reach around 14.8v with full regulation.

The one I have works up to 15.1v.

It's something other than the LM339 OVP circuit.

Just put a 680 ohm resistor in line with the pot to stay below 14.8v.

Also, pins 3 and 4 from top left on the large PIC are tach outputs from the fans.
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Last edited by xandrios; Jan 31, 2012 at 04:43 PM.
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Old Feb 03, 2012, 10:35 AM
Power! Power! Power!
HaxNobody's Avatar
Joined Jan 2012
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How about 2100 watts at 12.1 VDC? Dell NC003 blade server PSU.

Linky: http://www.serversupply.com/POWER%20...DELL/NC003.htm

Wonder If I should procure one and try to get it working.
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Old Feb 03, 2012, 12:54 PM
Steven
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United States, CT, East Hartford
Joined May 2010
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Hey HaxNobody ,

Or here for 1/4 the price:

http://www.ebay.com/itm/Dell-Powered...item53eb3f76c7

Why do they always have to raise the price when you start buying them??
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Last edited by xandrios; Feb 14, 2012 at 05:42 PM.
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Old Feb 04, 2012, 12:14 PM
Power! Power! Power!
HaxNobody's Avatar
Joined Jan 2012
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Quote:
Originally Posted by xandrios View Post
Hey HaxNobody ,

Or here for 1/4 the price:

http://www.ebay.com/itm/Dell-Powered...item53eb3f76c7
Score! I bought one, as well as a newer current-generation model: http://www.ebay.com/itm/320841281011

The second one is a 2360 watt 12VDC

Also, after hours and hours of googling, I finally found the spec sheet - with pinouts! - of the 48 volt PSU: http://www.powerconversion.com/suppo...cef3be3a5422a2

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Old Feb 04, 2012, 01:53 PM
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United States, CA, Sacramento
Joined Jan 2012
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hi,

just bought two of these to run in series. what is the current share pin used for? i thought it was something to do with parallel operation as they would be when installed in the server.

thank you

Quote:
Originally Posted by xandrios View Post
Hey 376782,

The Dell 7000245(Poweredge 6650) PS is an oddball PS where you have to ground bias the voltage control pin.
This may also be why the manufacturer selected to keep the DC ground floating on this model.

Pin A1 controls voltage. Connect to ground via pot or resistor. Use only up to 13v max.
1.3k ohm ≈ 13v. Any higher than 13v will cause the PS to shut down even with a slight current draw. This is common with most PS as you near OVP.
Tested at 13v for 72A.
Pin D1 is the current share pin.
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Old Feb 04, 2012, 04:25 PM
Steven
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United States, CT, East Hartford
Joined May 2010
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The current share pins are connected together when running them in parallel to balance the current draw between power supplies.
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Last edited by xandrios; Apr 06, 2012 at 07:39 AM.
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Old Feb 04, 2012, 04:36 PM
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United States, CA, Sacramento
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great, thanks a million!
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