Power Supply - Using a cheap LED strip light driver

[maca55]

I have a Hyperion 1420i 550W charger on the way and so am on the hunt for a high power (>700W) 24V supply for it.
I've seen posts with 2x 12V Server Power Supplies hooked together in series which looks like a nice reliable solution, but unsure where to get hold of these quickly and cheaply in Australia.

I have noticed on on ebay and other Chinese shopping sites etc an abundance of cheap 12V, 24V and 48V switching power supplies. They are usually listed as a "Power Supply Driver For LED Strip Light Display" or similar. eg)

24V 15A 360W DC Switch Power Supply Driver For LED Strip Light Display
http://www.buyincoins.com/new_en/de...-led-strip-light-display-2-product-12249.html
Or
http://www.ebay.com/itm/24V-15A-360...r-For-LED-Strip-Light-Display-2-/270931957632

At $27 each and free shipping, I could have two delivered for $54 giving me a cheap 24V 720W supply for the Hyperion charger.

Apart from quality (another reason to buy two), is there any electrical reason why these are unsuitable as a PS for chargers?
Does anyone have any experience in using these as PS for their chargers?

 

[dogman dan]

I didn't look at both, but the first one is a copy/clone of a Meanwell power supply. They can be ok or not. Real meanwells have a good reputation as both power for RC chargers and as bulk chargers after a small hack.

My first one I knew was a clone, and it fried itself nearly immediately. The second one was a Mega Watt, and not looking so close I thought I was getting a real Meanwell brand. It's worked flawlessly now for over two years.

Like all the cheaper priced china stuff, pay your money and take your chances. When I bought the second PS, I did make sure to get it from a vendor located in my country. Then bitched at the guy, and he made it more clear that the brand was not meanwell.

 

[Hillhater]

Server PS units are readily available in Oz.
I bought a pair of 500W 12v Dell units for $20 off Ebay ( Sydney vendor)
Ask around local computer shops etc as these server units are often swapped out after a year or two, and tossed as junk.
Much less of a gamble than cheap Chinese electronics !

 

[heathyoung]

I sell these pre-modified (ground mod + always on + fan mod) if you are interested.

 

[maca55]

Thanks everyone for the advice. Here is an update:

I decided to hedge my bets and ordered the $27 24V 15A 360W PS from China, but also contacted Heath and bought a pair of modded ex-server PS's in a 25V 1100W configuration. The PS are to power 2x Hyperion 1420i chargers.

I have been using the 25V 1100W PS for a few weeks now and it hasn't missed a beat. Well apart from one charge when one of the supplies tripped. Interestingly after this trip, the Hyperion charger had developed the dreaded 'Output Circuit Problem' fault and now will not charge any kind of battery I throw at it - luckily I bought two.

The other Hyperion is at work and is being powered by 2x Turnigy 14V 16A 220W supplies I already had. I checked to make sure the DC was isolated and then connected them in series to give a 28V 440W supply.

The cheap 360W PS from China was still sitting in the box until this week when my Hyperion charger dies and I needed to quickly get some charge in to my battery pack to get to work! It has an adjustment pot that can vary the output voltage from 20V-30V so I thought I'd give it a go for a quick and dirty bulk charger. I split my 12S LiPo pack into 2 x 6S 12Ah and plugged them in parallel. With a Watt Meter plugged in line to keep an eye on the current I adjusted the PS to 0.4V above the pack voltage and connected it up. It started pushing in at around 10A and an hour later, with 3-4 more small voltage adjustments I had bulk charged 10Ah/240Wh and the individual cells were balanced at around 4.15 +/-0.010V per cell.

The $27 PS is now my work charging solution while the Hyperion is out of action. I have just completed my 4th bulk charge with this cheap little 360W supply and have managed to get the voltage adjustments down to 3 per charge on a 50% depleted 6S 24Ah paralleled pack. I have pushed the supply to 16A and 380W and it did not cutout. So based on the success so far I decided to buy another (at US$25 delivered its hard to resist) and plan to put two in series to make a US$50 48V 720W supply for bulk charging my 12S 12Ah LiPo pack without the need to split and parallel the 2 6S packs. They are already DC isolated and the 15A max is just right for charging my 12Ah pack at 1C and I am hoping that in this configuration I may be able to get away with less voltage adjustments when charging.

Meanwhile at home the 25V 1100W supply got a real load test the other night direct charging my 6S 12Ah battery. With the pack at 22.67V and the PS at the fixed 25V it pulled an initial 49A and 1122W without tripping. The current dropped to 36A (3C) after 1 minute, 24A (2C) by 8min, and by 14 min it was down to a healthy 12A (1C). At 15 minutes it had already pushed in 6Ah to the pack! Needles to say these ex-server supplies are very capable, and if they had an adjustable output voltage they would be even better!

 

[heathyoung]

You can adjust the voltage ~ I posted a thread on these a while ago showing how they can be set up for constant current - it isn't too hard (in fact it is pretty easy to adjust the output voltage on these, just need to know which pins to use. From memory you could adjust down to 10V and up to about 13 or so.

Good to see you tried out the supplies with a serious load - They usually only trip out when they hit their current limit - I reckon that your hyperion has a smoked MOSFET or two in it.

 

[maca55]

You can adjust the voltage ~ I posted a thread on these a while ago showing how they can be set up for constant current - it isn't too hard (in fact it is pretty easy to adjust the output voltage on these, just need to know which pins to use. From memory you could adjust down to 10V and up to about 13 or so.

Awesome, I'll check that thread out: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=47415

Good to see you tried out the supplies with a serious load - They usually only trip out when they hit their current limit - I reckon that your hyperion has a smoked MOSFET or two in it.

Yes I am very happy with their performance under load. It's always nice to know you have the capability to quickly put 300Wh in to your pack.

 

[maca55]

UPDATE: It turns out that these cheap supplies have a built in Current Limiting feature.

So when using them to direct charge 6S LiPo there is no need to adjust the output voltage up step by step to keep from tripping the supply. You can simply set the output voltage at 25V and regardless of how discharged your 6S pack is, the PS will not deliver more than 15A, or 375W. Current will ramp down once the pack voltage increases just like a normal charger.

I'm using this as my work charger now and it charges my paralleled 6S packs in around an hour. You of course need to keep an eye on voltages to make sure the PS voltage doesn't drift high for some reason. Once the next one arrives I'll report back on how two of them in series will perform charging my 12S 12Ah pack at 15A to 50V.

 

[maca55]

UPDATE:

Currently using two of these 24V 360W $25 supplies connected in parallel to supply a Hyperion 1420i with a supply of 28.5V 700W.

Connecting these in Parallel means that the current isn't shared equally. I've adjusted the voltages on each so that when under full load (approx 20A) they both warm up and their cooling fans come on. The uneven current sharing isn't a real problem since these have built in current limiting set at 15A. Worse case one supplies 15A and the other 5A.

I've been running them in this configuration without issue now for 6 weeks / 30 charges. However if I was buying again I'd buy two 12V 360W supplies and link them in series so they share the load properly.

 

[Hillhater]

maca55, have you an idea what the max voltage adjustment range is on these 24v units ?
I have heard it may be as high as 30v, but need to verify as i am planning to series one up with a 12v server psu to charge a 10s lipo at 41v.
I notice also that there is a 400w 0-24v adjustable output version also available, which may be more "flexible" for this option.

 

[maca55]

maca55, have you an idea what the max voltage adjustment range is on these 24v units ?
I have heard it may be as high as 30v, but need to verify as i am planning to series one up with a 12v server psu to charge a 10s lipo at 41v.

I can confirm they definitely adjust up to 28.5V as this is the voltage they are currently set at to give the Hyperion it's max output power capability.
When I'm back at work (unfortunately off sick today) I will check for sure, but for memory the range was around 20-30V.

I notice also that there is a 400w 0-24v adjustable output version also available, which may be more "flexible" for this option.

I haven't seen this version before. That would make for a very flexible solution indeed! Although it probably won't adjust as high as 30V (otherwise you would think they'd advised it as 0-30V adjustable right?).
Maybe you could post a link to this version?

 

[Hillhater]

Here is the 0-24v version...
http://www.ebay.com.au/itm/EIR8-NEW-Switch-Power-Supply-Driver-For-LED-Strip-light-Display-0-24V-16-5A-400W-/121111775369?pt=AU_B_I_Electrical_Test_Equipment&hash=item1c32d30889

 

[maca55]

Static Output voltage can be adjusted from 20.16 Vmin to 30.80 Vmax

 

[Hillhater]

Hi Maca55,
Thanks for the info.
The 0-24v version literally just landed on the doorstep, and initial checks show the unloaded voltage range to be 0 - 27.5v.
(Anyone know what happens if you flick the input voltage switch to the 110v setting and feed it 220v ? ) :lol:

EDIT ..
FYI .. just topped off a pack (30Ahr, 5s) for a test.
Set the PSU to 20.5V, pack at 19.3v before charging.
Initial charge at 10.5A, and slowly decreased to end at 0.2A with the pack at 20.3v after about 3hrs.
Total 9.6 Ahr charged
No problems , the fan only came on a few times for 30 sec or so during the 10 A period.
Quiet ( silent most of the time)
so far so good.

 

[maca55]

Hillhater, Good information on the new 0-24V version. Is 27.5V max enough for your application?

(Anyone know what happens if you flick the input voltage switch to the 110v setting and feed it 220v ? ) :lol:

Haha are you game to try?

I'm interested to hear if it's current limiting works as nicely as the 24V versions and what actual Amps is limits at.

the fan only came on a few times for 30 sec or so during the 10 A period.
Quiet ( silent most of the time)

The 24V 360V versions get rather hot on the end opposite the terminals where the MOSFET is mounted. An external heat sink mounted on the end would no doubt help with longevity of this MOSFET. The fan is controlled my a simple on/off type thermostat that is dangling in the case. I wedged it under the MOSFET mounting clip to try and get the fan to run more often. Is the 0-24V using the same dangling Tstat?

 

[Hillhater]

I dont really need the 27 v option, as i will mostly use this to fast bulk charge my 10s pack that i always charge as a pair of 5s packs to 20.5v
I also have a pair of 12v 51A Dell server PSU's that i use to power balance chargers, so i could hook those up in series with this LED driver to bulk charge at 41v...but that would be messy ! ( isolation and all that.)
I may just get another one of these 0-24v units as both a back up, ( its gonna die eventually !).. and giving me the option of a simpler 41v supply.

From an initial quick test, current limiting seems to work ok and hits the stop at 16.56A
I havent opened up the case yet , but will report back in a few days.

EDIT:
Maca55 ..you mentioned previously that your 24v PSU's are already DC isolated.. how did you check/confirm that ?

 

[maca55]

Maca55 ..you mentioned previously that your 24v PSU's are already DC isolated.. how did you check/confirm that ?

I'm not an electrician so am happy to be corrected on the right procedure here, disconnected from mains I just used a multi-meter to check for any continuity between the DC output terminals and: L, N, Earth, and Case (No harm in checking them all)
No continuity on any of the above means the DC output is isolated and so no problem putting two in series even with the cases touching.