Server Power Supply HP DPS-750RB
 

Converting power supplies for RC charging was sometimes a bit of an art form. I've followed many threads, builds, and articles on the subject. Trying to figure out which pin outs would turn on the PS, and make them work. I had a PC in the basement just waiting to be torn apart. Did I really want to go through the hassle just to get 250 watts? No. After looking at different power supplies, and not wanting to mess with a bunch of wires, hot-pluggable server power supplies seemed to lure me in. Just by chance, I happen to be searching on Amazon for a power supply and seen one that had two long strips (+/- terminals) to work with. Well I don't think it gets any easier than this one...Amazon search for 750W Cs He Power Supply Kit will have options for sellers. I got mine new, from Computer Supply.

• HP 750 Watts CS HE Gold Power Supply
• 62.5A maximum
• Part #: 511778-001
• Option Part #: 512327-B21
• Device Type: Power supply - hot-plug
• Assembly Part #: 506821-001, 506822-201, HSTNS-PL18

For $16, and free shipping...I had to try one out. Well, in theory, I think server power supplies are the way to go. There were a lot of same/similar power supplies being sold as refurbished and costing the same, or more than the new one I purchased.

Will this work out, and be leading me down a path to a new charger?
How much will the output voltage drop when a "heavy" load is placed on it?
The one I chose says it will output a lot of amperage. We will see.

Cover for the end of power supply: https://www.rlpower.net/products/cover

UPDATE 8/17/17: The power supply was used to power three chargers, and they were pulling 50 amps from the HP DPS-750RB. The lowest voltage reading I got was 11.24v so far.
Attachment 2228314Attachment 2244894
It doesn't get any easier, unless you buy an already converted power supply.

One Wire
 

Bridge tabs 33 & 36 together, and that is it! Well, you do need a universal power cord to plug the unit into wall outlet. One piece of wire, fifteen-second solder job, and we have 12 volts pumping out of the unit!

Little Testing
 

Did some quick testing. El cheapo B6AC80w showed 12.36v input power. I don't know if that is a good "number", 'cause I don't trust the test subject (B6AC80w charger). This particular charger has it's display crap out on me almost every single time I use it. I unplug the charger and it works fine the rest of the day (unless it gets warm...like in direct sunlight).

Anyways. Excuse my plethora of connectors :p. I hooked up another charger (dual charger) while charging two 3S packs at 8.2 amps each. I got an input reading of 11.4v for the charger. I moved onto hooking up both chargers (single port and a dual charger). During my three 2S LiPo pack charging (sorry, forgot to take picture), I got both chargers maxed out; one at 6 amps, and the other charger at 20 amps. My input voltage readings were 11.8v on the dual charger, and 12v on the single port charger.

Once I receive my 4mm bullet sockets, I'll get things soldered onto the power supply, and try to pull 50 amps from the HP DPS-750RB unit.

update

Last part to arrive for this power supply conversion. I know, now, I should have sourced the tubes from USA supplier after other parts started to come earlier than expected. I wanted 4mm bullet tubes so I could connect a few chargers to the SPS (server power supply) securely. For me, testing with just alligator clips was okay when I was not putting all of my chargers at maximum output.

Got the tubes all soldered up, and covered with heat-shrink tubing.

3D printed cover for the end of the server power supply. It's not really needed, but I think it gives a nice look with some protection from accidental bumping.

Voila!
 

Three of my chargers maxed out for a combined total of 50 amps . Voltage sag on the SPS is 11.4v~11.5v and the SPS fan was not overly noisy. I only had the chargers going for 5 minutes though. This being my first attempt with a power supply, I was expecting the voltage to drop more than it did.

EDIT: Plugging in the numbers, amperage was helped along by a theoretical 420 watts from the HP power supply.

I did another round of 50 amp charging and the power supply voltage dropped/fluctuated between 11.24v~11.32v. I can live with those numbers, as I do not charge my packs greater than a 1C charge rate too often.

I will add, the HP DPS-750RB's fan did "ramp up" a bit at the 6 minute mark. Definitely not a as noisy as the my Ultra Power charger's fans (one sucks air in; one blows air out).

nice work... there is a lot of conflicting information online its good to see someone has put the time to read between the lines... well done sir!!!!!!!

that one seems easier to modify then the ones I've used in the past for power supplies for various things.
Nice job

Ok I think I will tackle this. For 15 bucks what the hell. I bought the power supply. What else do I need to buy. Can you link me the the bullets on amazon? Do you think you can print me another cover??? What else do I need?

https://www.amazon.com/HRB-Battery-B...llet+connector

or?

https://www.amazon.com/YoCoo-Plated-...llet+connector

Either of those 4mm bullets in the links will work.

A small piece of wire is the only thing you need to solder to turn on power supply. I only soldered 3 sets of bullet tubes on the tabs, 'cause I didn't want to get things too crowded. I do believe this is the easiest conversion a person could do.

I got some vinyl wrap to put on yet. Will try to make the server power supply look more presentable.

3D Top Grade BLack 12" x 60" Carbon Fiber Vinyl Car Wrap Bubble Free
Cover for the end of power supply: https://www.rlpower.net/products/cover

When I went to make my wire charger leads, I noticed my two main chargers use XT60 connectors for DC power input. That's one type of connector I've never used, so I had to go out and order those as well.

I'm glad I went through all this soldering, and stuff. This little project has lead me to such a great connector...the XT60. I'm all turned on with the XT60 connector. I'm now in the process of converting all my connectors over to them...bye-bye Deans, and EC5

I use xt90

For sure I'll be using XT90s, for my battery leads, when the 4S packs start to roll in. My little HP power supply project involved no other option but to use XT60 for power input to my chargers.
http://www.rcuniverse.com/forum/atta...1&d=1482802315http://www.rcuniverse.com/forum/atta...1&d=1482179985
Now that I have a new "go to" connector that will last me *fingers crossed* the next 20 years of RCing, I wonder how long the new power supply will last with moderate usage. Hopefully, power supply being a HP (what I think is a good brand), will last until the zombies come knocking at my door ;).

I think of buying the hitec x2 700w for 170 through tower. Any thoughts on it? I do not know yet if I should zero in on that. I mean I already bought the power supply and all or I should get the hrtc triple ac/dc 200w per channel for 180...

That charger would be great if it fits your needs. I don't know how many cells you will be charging, and how fast you want to charge. If charging 6S 5000mAh packs up to a 5C rate, your okay. LiPo packs with more cells, more capacity, and their maximum charging rate will be needed to narrow down power requirements.

im charging 6s at 2c. would it matter if I went overboard on the solder? it is not bridging the +/- but it is pretty much on all the + tab and - tab. first time doing this...

As long as the + and - sections on the PCB are not touching, you're good to go.

here is the pic

aa

atleast the tool box came out better

Yes, Androdz, you may have went a little overboard on the solder. If I ever think I have a short between the +/- on circuit boards, I use the back side of my X-acto blade to gently scrape a gap in the solder.

It worked perfectly fine with my gt1000 duo. Might buy another and run both. Any idea on how to make it 24v?