Hi,

I need USED server PSU to modify them for charging purpose.

Preferably these models:

1. Dell NPS 700 AB (two units)
2. Dell 6650 (two units)
3. HP ESP120 (3Kw)- One unit
4. HP DPS 600PB ESP135 series (two units)

Kind Regards

Any specific reasons for a server PSU?

A simple SMPS such as Quantum, Frontech is more than capable of providing the current required. You can easily avail currents of about 18A order (in fact more) on a single rail

GS

Hi girish.

Check ur PM.

Doc

Coz i need > 40 amp .

Though it is written as 14A in 12 volt on any SMPS, Have you ever load with one 100watt and one 50 watt car headlamp ? Most of them will release smoke as internally they use 3A rectifier diode with heatsink resulted to 8A. When replaced with MOSPEC 30C45, Transformer (HF) smoked. What a degraded items now opened sold in market. (No ISI but with CE).

Doctor,
Best choice is go for transformer based regulated power supply unit fed through CVT/Servo stabilizer. Use 1KVA isolation transformer CRGO Core and electrolytic coil conductor. You can ask your local battery center (Preferably one side i. e. Exide ) for 50A charging transformer even thyristor controlled with feedback for an ready-made one.

Kalyan aren't thost transformers costly ?

Sorry to hijack the thread , but I'm looking for a power source which can give me 12 v @  18 - 25 amps ( 24v at 30 amp preffered).. I've heard , transformers at that rating are quite expensive so making them myself would mean $$$. Looking for other alternative sources , any ideas

@Srivatsa - 12 volt 18-25 amp is easily available with a good PSU like cooler master.

@Kalyan and Girish: HAve you modded a cooler master pro hybrid 1000 watt PSU ? Though, again it is 12 v only......

I want Dell Psu which i will join in series to get 24 volts.

@Doctor , i know its easily available,  but expensive , no point in using for mods . . And btw check on ebay.. 24v 36-40  amp power supplies are available, costs the same as computer smps.. Most of them use it  for hobby grade cnc .., just search for cnc power supply.

98 Amp is not the continuous current rating. At least PCB Tracks are not ready for 98A as per their picture. However I does not own it so that I can give test data. for 98Amp, you need at least 10 sqmm of copper taking 10A/Sqmm current dencity (Assuming Electrolytic Cu). MOSPEC Rectifiers are 40A max rated and beyond which (100A & above) their construction changes for heat sink fixing arrangement. If 100A become so easy, welders should use this with inductor. Look, they have no ISI mark for claim. Technology are changing, they may go silver winding over f. core transformers (Else space would not be so small even after forced cooling), with MOS based Synchronous rectifiers and they give 5 year warranty. So please use this  and enlighten us about their test data.

Dear Kalyan da, i am no genius to enlighten you or anyone else here on the forum. Infact, my knowledge compared to you is miniscule regarding these transformers and mosfets etc etc...

To max out my FMA PL8 v2 charger, i need 24 volt , >1000w at 40 amp plus...Hence, i need the server PSUs...

http://www.rcgroups.com/forums/showthread.php?t=1292514

https://sites.google.com/site/tjinguytech/my-projects/diy-24v-47a

This thread explains how we mod the PSU for series connection and i believe with my limited knowledge and soldering skills might be able to do it.

Was just checking the PSUs and came across cooleer master and corsair, so i asked the question "has anyone modded them".

Girish is nearest to me here in Delhi, will get in touch with him before i attempt a mod.

But at the moment i need the used server PSUs.

Bump..any Rc flier into computers PSUs? Will be thankful to him if someone can arrange

So, 24 volt 40A is your requirement. Why not go to nearest Fan/Motor repairing shop that repair stabilizer too, and ask him the cost of transformer based PSU ? I can arrange/ask in Kolkata, but in delhi you would cost cheaper than Kolkata and less postage. Belief me, It will be more robbust and for life long. You may ask Exide battery dealer for the cost. Please enlighten us about the cost comparison.

Please note that efficiency is much better in Transformer based charger and that is why large capacity commercial chargers are always transformer based. but if you need a portable lightweight charger, SMPS is the best option.

Hey thanx Kalyan...

Got ur point. Will begin the market survey tomorow.