***Disclaimer*** I am not a professional and make no claims to be an expert, however I am sharing my successful experience with you to see how I saved some cash and recycled some parts to put to some good use with my R/C hobby I have actually found it easier to convert a Server power supply than a PC supply, first I will show a PC Supply, then a Server Supply farther down in this post. There are several other Server Supply examples posted here:
Here are some pics of my conversion project by recycling an Allied Power Supply designed for use in a personal computer. I actually got mine for free out of an ad on Craigslist under the free section where someone gave away an older PC with a bad motherboard:
If you look carefully at the specifications, this particular PSU can provide up to 16A of combined current on the +12V (Yellow) wires which are the wires that I will plan to power several of my DC chargers with.
EDIT 23-AUG-2011 Bill DeLong said
Note that 16A x 12V = 192W. I have actually charged 6 x 2S LiPos against this PS with a confirmed pull of 284W so I believe the "Combined Power" rating of 330W trumps the 192W implied limit on the label in my experience with this particular PS.
The first step (after unplugging the power supply) is to join the green wire with any black wire. The green wire is designed to be used as a switch for the PC, but an extra switch is not necessary because the PSU itself has its own GFCI load protected switch next to the fan:
The next step is to install a 10W x 10Ohm resistor between the purple (+5V) wire and any black wire. This will provide a constant load on your PSU to ensure that you get a clean 12V source:
Then you want to determine how many devices you plan to hook up to your PSU. Be sure to tuck the remaining wires back inside the unit and tape the ends so they don't accidentally short out. These extra wires may be used in the future if you plan to add additional devices to your PSU. Note that I was able to tuck the resistor nicely between the heat sink and the rear vent holes:
In my case, I chose to have 4 x 12V (Yellow Wire), 1 x 5V (Red Wire) and 1 x 3.3V(Orange Wire). Simply solder on your connectors, I prefer Deans style, then screw the cover back on and you're done:
Here is the final assembly powering 4 DC chargers:
Thunder AC6 rated up to 5A (Note this is also a DC charger which I prefer to have a single on/off switch at the PSU to control all my chargers with)
I would like to give credit to MajorPede for providing me with the following resource so that I may come up with the design for this particular install: http://web2.murraystate.edu/andy.bat. owersupply.htm
I recently purchased a Thunder T6 Charger will pulls up to 200W and discovered that the heat was too high for my comfort on just a single 18ga wire. I decided to solder a total of 3 wires to each lead in order to solve my over heating issues to power the T6:
Some folks have been experiencing issues with their PSU not properly working which have required them to wire Brown to Orange as explained on post #97 here:
guys2nv Post #97:
AHHHHHHHHHHHH, I got it to work. After reading this page: http://web2.murraystate.edu/andy.bat. java_table.htm. Look at the last part that says "Doesn't work" The part about the sense wire (Brown) You have to hook it up to a +3.3v source (Orange wire) Then try again so this what I did and put it all back together and IT WORKS. Put a multimeter to the deans and got 12.2V on all yellow wires, 3.5v on my orange and 5.5v on my red-SWEEEEET.
Also take special note that GUYS2NV fix was only good for 2S charging, he was not able to get 3S to charge properly when making the mods to this following PS
made by Logisy:
Another user BULLET1 was having issues with his 85W PS where everything worked fine when charging 2S @ 5A, but 3S could only handle 3A loads when balancing his cells, if not balancing, then he could charge 3S @ 5A. For some reason, his PS would get overloaded and the voltage would drop below 11V causing his Venom charger to error out.
Another user Kurtus is having problems (see pages 18-19 of this thread) with this PS here where the charger must be hooked up first when powering on the PS otherwise the PS will reset if trying to plug in the charger or any additional charger after the PS is already running:
I just finished converting another PS from Dell HP-U2106F3 which supports up to 144W. Basically I followed every step outlined above and no variations were necessary as seen here, green wire soldered to black, and the 10 W x 10 Ohm resistor is soldered to the purple + black:
I chose to use only the five +12V Yellow wires plus five black wires such that 3Yx3B go to one connector and then equal pairs of YxB go to the other 2 connectors. This allows me to run 3 x 50W chargers or a single 150W charger off the 3Yx3B connector:
Note on the label that is says max combined output power is 210W however the +12V rail only supports 12V x 12A = 144W. I hooked up my T6 (200W) charger and was able to pull about 150W without a problem, however the PS shut down once I tried to pull 200W:
I also verified that this PS could charge 4S LiPo with the balance port enabled:
If you are curious on how I was able to wire two 2S packs in series with balance ports as a virtual 4S pack, please follow this thread here:
I recently converted another PS from Mitac (72W)
Rather than show a bunch of the same pics, I did all the same wiring as the other 2 PS's previously, only difference is that this PS only has 3 yellow +12V wires, so I simply soldered all 3 together into a single output because this PS can only provide 72W of power on the +12V rail:
I also converted a 64W laptop power supply which was quite simple:
I recently sold a charger + the AC Adapter pictured above to another URC member, he had no problem charging the first pack just fine, but the power supply burned up on the second pack
I have never used the charger for back to back charging, I highly recommend checking the temperature of the PS and do not let it get any warmer than 120°, also let it cool down between charge cycles and don't leave it plugged it while not in use.
I bought two 585W power supplies designed for servers off eBay for $20 shipped!
I used my voltmeter using the DCA option of my voltmeter. For the IBM 24R2639, you have to connect Row A - Column 8 with Row B - Column 4 as seen here which switch the unit on/off:
I found some spare 1mm thick plastic that I was able to cut to fit and slide in between the slots of the connector. I also used my rotary tool to grind away access to the pins and soldered directly on the connector itself:
I stress tested the PS to verify no resistor was necessary, I was able to hot swap different chargers and simultaneously charged three 3S packs and two 4S packs without any issues. The fan on this supply is considerably louder than the traditional desktop PS, but having 585W of power sure is worth it!