Cheap 32Amp 12V PSU for LIPO charge -HK PSU went BANG! (UK)

[GaryJS]

Hey guys,

After my Hobbyking 35A PSU went up in smoke on it's second outing (whilst pulling only 4 amps!) charging my new lipo, I was looking for a new power supply - Just a heads up - there are some HP DL380 G3 server power supplies on Ebay (UK) for £4.50ish at the moment - HP part code HP #194989 - ideal for me with my hobbyking 4x6s charger (50W per channel) since it's rated at 384W! I looked at PC power supplies but they seemed like more of a faff (you need to load the 5V and 3.3V supplies to get a steady 12V) and didn't give as high a rating on the 12V (typically a 300W supply had a 10Amp rating for the 12V line).

There are some instructions on how to get them running here:
http://ohiopacket.org/files/docs/Powersup.pdf

I modded mine to have banana connectors too

Hope this is of use to someone!

 

[Hillhater]

good choice ! :wink:
there are many similar server PSUs that will re purpose as charger PSUs if you can figure out the "hot wire" to fire them up.
HP and Dell see the most common with PSUs of 500w, 800W , and even 3000W capacity. voltages up to 50+v also.
Several threads on these forums to help.
Now that you are happy with that one, i suggest you buy another as a back up, or several and series them together for fast bulk charging. :wink:

 

[Sunder]

good choice ! :wink:
there are many similar server PSUs that will re purpose as charger PSUs if you can figure out the "hot wire" to fire them up.

If they're ATX based (Including extensions like 20 and 24 pin ATX), it's always the green wire to any ground. (Black wire)

 

[Hillhater]

Good info Sunder ...for computer PSUs,...but ...
SERVER PSUs do not have coloured wires hanging out ! :wink:
Infact most server PSUs have NO wires at all...only contact tabs and a large array of "control" pins that need to be connected in the correct sequence to get any output from the power stage.
Check some of the server psu threads.
This is typical of what you face with a server PSU

( this one is already modified and wired )

 

[sn0wchyld]

this guy https://sites.google.com/site/tjinguytech/

has some great info on modding the supplies to run in series. im using 2 hp supplies atm for 24v 55A and lovin it

 

[LI-ghtcycle]

I feel your pain!

I bought what I thought would have been a rock solid PSU at the local hobby shop, and it managed to kill my first LiPo charger also bought at the hobby shop, (this was a 12V 20A plug in the wall affair that you had to dial up to 15V to maintain any real consistent wattage) and I wasn't even using a high out-put charger at first.

I didn't realize this was the problem until I bought a hyperion 1420i, and it kept giving me an "input voltage error" (well, my second hyperion did, because the first one started having problems, and I finally realized it was because of the $90 PSU that I bought that was "good" :lol: )

I then went on Ebay, found a nice 480W 24V 20A Meanwell clone that was being sold by a seller with a good record specifically to feed that high out-put of the hyperion, and I have had no problems since.

http://www.ebay.com/itm/24V-20A-Swi...175?pt=LH_DefaultDomain_0&hash=item4154ac92df

Just wanted to say it's not just the "cheap" stuff from HK, it's a quality control issue, I probably mainly a result of too many consumers still buying cheap throw away stuff instead of insisting on better quality for a higher price, I buy stuff from HK too, but only the highest rated, and generally "safe" items like the higher end LiPo, simple items like bullet connectors (hard to make those go bad hehe).

 

[whereswally606]

Thanks for the find GaryJS
Ordered two of these a while back with the idea of doing the mod in your pdf. I havent yet done it cause i was thinking i might try to make a custom pcb connector which clamps to the PSU output pcb and does the grounding of the correct pins as well as linking to banana plugs or 4mm bullets.

Dont suppose you got any pictures of your mods to this PSU so I can see how you got it working?

 

[Spicerack]

I bought one of the HP dlwhatever server psu's- the same one as in the second photo a few posts up, where he has done a ridiculously neat job of the wiring (power take off's either side of the control pins. The servo plug is no doubt connected to a switch- these three pins have to be connected to turn the supply on.

The only problem is that whe you turn it on, you need to be holding on to something- it has two ducted fans inside it that just about suck you in!

They are seriously loud, so I did the resistor mod to slow them down a bit....

But yes, 100A at 12V is probably sufficient!

RC groups has some pretty good threads about modding these server psu's.

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

 

[whereswally606]

Right, bit the bullet and had a go at getting these power supplies operational.

here are some pics of the handy work with the soldering iron.





after i read the pdf at the start of this thread (which is so absolutely clear even I got it right) I tried the power supplies out. they came on in a different way to how they would if i hadnt done the mods but no green, im a happy server power supply led. This was contra to what the pdf told me would happen. So anyway i cracked out my cheap maplins clamp multimeter. the +12v line read 9 to 10 volts which was a bit disappointing, at this stage id only modded one of the two i have. Then i thought ill take my GT power meter of the bike in the garage and see if it can improve on 10 volts. It read 11.15volts which was a bit more like it but under what i expected. Anyway the point of this was to get my hyperion 1410 powered to i took a gamble read the box and saw that the min voltage required to run it is 10.5 volts. I plugged it via the load on the GT power meter and all was good. This was doubly satisfying since before today i had no idea whether my hyperion or my server power supplies worked. Then i got on to modding the next realising that perhaps thought an led is nice to see it perhaps is not necessary since ill just put a GT power meter in between the psu and the hyperion anyway.

Anyway conclusions, If i series these in their current state ill get 22V (i need to float one of the DC grounds) and perhap if i locate the trimpot for the voltage I can do better but really it doesnt bother me that much. The PSU took very little time to mod once i got on with it and I may spring for a load more to make sure i got a few spares and perhaps might build a good bulk lipo charger. who knows.

lastly thanks to GaryJS for putting up the ebay link. these things are not so easy for the UK guys to check cheaply. but great so far.

 

[psycholist]

Whereswally, Why did you omit "interlock 2" (pin 11 to ground) ?

 

[psycholist]

You should also wire all 4 edge grounds (top and bottom) together. This should give you +12v.

 

[whereswally606]

Ha, well thats one benefit of posting your exploits. Thanks pyscholist, the reason i negated to do the second interlock was down to being a complete tard and not reading all the info in the pdf. the last bit of info was on the next page and i was reading it straight from my laptop so i didnt see it. Thanks for catching that, will get on that and the gnd connections too then gonna float that DC ground and get my 24volts. Ive got a uni exams tomorrow and this is a perfect example of read the bloody information, ie all of it.

 

[psycholist]

Yeah, I can understand how the last instruction on the second page could easily be overlooked.

Tip: You can connect all 4 grounds with 1 wire by stripping a little extra off each end.
Then wrap ends around edge of board (connecting both top and bottom grounds).

Thanks for rejuvenating this thread! I forgot about this particular PSU.

Keep us updated with your progress (voltage, ground isolation, series connection) with pics

 

[whereswally606]

I tried to phone HP today to see if i could get a service manual from them for the 194989-002 power supply. Unfortunately all i received was a sorry we do not aid the customer in repair we only swap the PSU.

Can anyone help me out. I need to be sure of which line is the DC ground inside the case and i definitely dont want to cut the AC ground. This is so I can series this supply.

Regards Andy

 

[whereswally606]

To aid in helping me to do this ive opened up one of the powersupplies to take a few snaps so that the DC ground isolation method can be better shown. If you have done this before please show me your pictures or anotate mine.





View attachment 2

View attachment 6

All the pictures were taken and resized to 600 pixels to help uploading hope that they are clear enough.

Thanks to anyone in advance for help on this.

 

[GaryJS]

Hey guys!

Sorry for the long silence! I haven't been doing much work on my bike recently - cold weather, a 'technical issue' caused by some off roading (puncture on a wheel that needs two people to remove.. joy of hub motors on a frame that's too narrow!) and a general lack of time..

I can't be of too much help I'm afraid but did you know those two little potentiometers adjust the current limit and output voltage? You don't get a lot of swing but I got mine to pump out over 14V from memory..

 

[GaryJS]

P.S. I subscribed now! Cheers for the phone call! I could have chatted all day but I didn't even get around to mentioning I'm at work! Er herm - he says posting in the forum!! Ooops!