Get a LiPo Charger Power Supply cheaply – 1000W Server PSU

Ben Joslin shared his project with us, where he turned his powerful computer/server PSU into a LiPo chargers power supply, which saved him a lot of money.

Check out another DIY Charger PSU project we recently covered.

Make your own 1000W DC charger power supply

Recently, my power supply decided to give up and caught fire. It was fairly expensive and as the company i bought it from disappeared from the face of the earth, i started shopping around.

I was quite surprised that there weren’t many available at a reasonable price or those that were cheap, would probably break under the pressure i put them under. If you parallel charge like i do, it’s quite easy to get up to charge currents of 15 amps or more and an 80 watt PSU simply won’t cut it.

I had seen many computer bench power supply mods before but wanted something with a bit more punch to really make proper use of my icharger 208b (350W). I found cheap, small and powerful server power supplies. They are designed for high performance and use high quality components.

I decided on modifying an HP D800 server power supply which i purchased for £15 with free delivery on eBay. It is a 1000w power supply capable of providing 82 amps of continuous current at 12 volts.

HP D800 psu server power supply for lipo charger ebay

Parts Used

The other parts I used were:

  • Power connectors of your choice e.g banana sockets, female bullets or whatever suits the dc input of your charger
  • Small wire for using as jumper connectors
  • Solder and flux
  • Tools: soldering iron, phillips screw driver

Steps

The first step is to open the power supply. Make sure it is unplugged and you have left it unplugged for a couple of hours to discharge the capacitors.

Unscrew the screws on the top of the case.

HP D800 psu server power supply for lipo charger screw location

Unscrew the screws on the side.

HP D800 psu server power supply for lipo charger screw location open case

Release the mains kettle lead connector and unscrew the 4 board retaining screws.

HP D800 psu server power supply for lipo charger soldering

Turn the power supply upside down and lift up the base to expose the base of the circuit board.

Solder the jumper wires as shown below. This will allow the supply to output 12v whilst not connected to a server. If your power supply can take 14v, you can join the points marked (B) with a 2.8k resistor which will increase the output voltage to 13.8v. This will only work on this particular model. This is the maximum this supply with output before the voltage protection circuit kicks in and turns the unit off. Make sure your connections are neat and wont short with the case.

Reassemble the supply and prepare to add the power connectors. Flux the two pads on the top and bottom. I slotted my power connectors and soldered both sides to ensure a strong connection. The positive side of the unit is red and negative is the black side. Be sure to only use the pads shown here.

HP D800 psu server power supply for lipo charger connector pads

Put some large heat shrink over the positive terminals or liquid tape if you have it. This will help ensure you don’t short it when plugging in the leads to the sockets.

Plug the supply in and turn it on. The green LED on the rear should light up. You know have a very quiet and powerful power supply.

HP D800 psu server power supply for lipo charger battery

There are many, many mods similar to this and information on those can be found from a google search.

Safety Warning: this DIY hack is for people with advanced electronic/electrical skills only. You are doing this project at your own risk.

Author : Ben Joslin
Bio: Hates the term "drone", and I don't wear ladies underwear...

13 thoughts on “Get a LiPo Charger Power Supply cheaply – 1000W Server PSU

  1. adil

    i also figured out about the hp server 750 watt redundant power supply that we can get 13.85volts easily…
    i hope it will help you guys..watch the video and share with other friends..im leaving an link below..
    youtu.be/4P1-lpzYV1Y

    Reply
  2. Daniel l Lawrence

    Does anyone know if the jumper pins are the same on this model 512327-B21. Thanks in advance for any help

    amazon.com/gp/product/B0025B0FAW/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

    Reply
  3. Damian

    What was the reason for using a link wire ‘B’ in the photo, when you mention it requires a resistor to operate at the higher voltage?

    Reply
  4. G_lux

    I attempted this conversion but I ran into a small issue .

    As soon as I plug it in I get the green light to turn on for 1/2 a second. I also get 12v for that split second. After that the green light turns off and the left fan turns on and stays on. After that point I do not get any voltage output. Any ideas?

    Reply
    1. Wigglesdetroitfpv

      I had that happen on a bad psu that I attempted to use. Is the one you are trying to convert from an old computer that you forgot had a bad psu like I did? Lol

      Reply
  5. Alex

    When I did a server PSU conversion I installed EC5 connectors like the FMA Direct / Cellpro / Powerlab stuff comes with. None of my models use EC5 and EC5 also does not match the charger’s output connections. Because of this using EC5 eliminates the reverse-polarity risk while also eliminating the “battery connected directly to PSU” possibility…

    Reply
    1. Ben Joslin

      Its a fantastic middle of the range charger! I abolutely love mine. The packs balance really nicely and i run it on 20a paralell charges all day long

      Reply
  6. gazab

    EXACTLY what I was looking for! I just ordered the same psu off ebay. Not as cheap as this one but still way cheaper and better than most normal charger power supplies I’ve found. Thanks!

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *

Are you Robot? *

I only check blog comments once or twice a week, if you want a quick reply you can post your question on this forum IntoFPV.com... You might get a faster response from me there (multirotor related only).