Testing the HP ESP-135 Server supply and isolation modding.

[ZOMGVTEK]

Any SMPS experts out there want to figure out a cheap and easy way to make these current limiting to some extent? Even if its a narrow 'compliance' window, thats OK.

I'd like to be able to use 8 of these in series to charge a 96V SLA bank off generator power. I really like how 'substantial' these supplies are. They're very happy running off horrible generator power and handle violent voltage and frequency fluctuations. This is a big deal, since cheap SMPS and most every linear supply isn't terribly happy with that kind of stuff. Load down the battery bank, suddenly and dramatically increasing the generator load, causing the generator to bog momentarily. When that load is then removed and the generator is nearly unloaded, the voltage and violently shoot up and hunt around a bit. These supplies handle it great, most others do not.

I suppose the Fetcher Meanwell limiter could probably be modified to work with this? The idea here is to do this as inexpensively as possible and have it be quite reliable.

 

[HumboldtRc]

The best way to current limit them, is to get a current limited supply and use it in series with them. Get a 30 or 40 amp meanwell or some other ps.

 

[ZOMGVTEK]

All of my CC supplies don't tolerate the generators output under hammering loads. The ESP's usually do, always auto-reset, and happen to be super cheap. Plus, it helps that I have a mountain of them laying around. Even my Meanwell bulk charger is occasionally tripped and needs a power cycle to work again. I think ideally I need a high end switch mode charger with tons of input capacitance, but thats a bit spendy for how little use this setup might get. I'm not a big fan of running expensive high end supplies on a crummy generator when I know it's going to see some nasty voltage and frequency swings at some points. The ESP's can probably tolerate most anything a 120V generator can throw at it, which can be about 160V when you go from full load to no load. Loading it down with a 100W light helps some, but not that much. I'm just trying to shovel something together to be able to backfeed a few breakers in the house in case the power goes out for an extended period from this supposed 'hurricane' thing over the next few days. My 12V inverter I used to use for this blew up, so I'm left with some big online UPS's that run on a much harder to manage 96V of lead.

I just considered the option of putting the CC supply on the other side of the inverter so that it has steady power to be able to regulate current even with the generator surging... Kinda wasteful to use a linear supply to charge the battery bank its being run off, but it might do the trick. I'll try it out.

 

[Kin]

For those interested in current limiting these, a few pages back I and I think someone else posted links to the german group that a few years back made boards to modify these as current-limited. They did this by tuning into a wide adjustment range that's available on these and lowering output voltage when the current is high.

I never got too far into that though, because I ultimately used this guy along with a currie brushed controller in order to run low RPMs and sand with a big 24" double roller (using an etek clone that was sold to me as a genuine etek.) Didn't seem worth it past that, because I rarely have 220v available.

 

[ZOMGVTEK]

Kin, I presume you are talking about the ESP 120 model? This thread is about the 12V 120VAC 575W variant.

http://endless-sphere.com/forums/viewtopic.php?f=7&t=32829

http://www.lifepohandel.de/epages/63129206.sf/de_DE/?ObjectPath=/Shops/63129206/Products/%22Steuerplatine%20f.%20HPNT%20V2.2%22

The board is rather expensive considering how dumb cheap the PSU is. It's about $100 USD for a kit, to make a board, to psuedo CC a $20-40 3kW supply. Sill not a bad deal overall, but it really kills a ton of the appeal of a $30 3kW quality PSU.

 

[Kin]

Oops! I'm sorry. You're 100% correct, I was reading too quickly and mixing the two threads up.

I agree their kit is a bit pricey. Originally had it been more convenient and usable for 110v, I would have investigated replicating their project.

 

[diggler]

I'm thinking these would be great to use for a portable fast opportunity charger for touring!
If one broke on the road, yah I'd be stuck somewhere with no fast charger, but at least I wouldn't be out much money's.
(maybe I could bring a spare well wrapped up for bumps)
And I'd still bring a balance charger for the occasional balancing.
The only issue would be bringing along a robust CC/CV supply with, that you could adjust voltage and current with.
I was thinking this as the solution. In the 12V variety.
http://www.powergatellc.com/mean-well-HLG-600-power-supply.html
Yah it's 200 bucks but it's bullet proof and comes with a 5 year warranty.
So no matter what your desired voltage is. 48,60,72,84,96 you could just get x amount of hp's with the meanwell on top and charge at whatever voltage you want at 40Amps!
Not only that but you could dial down the amps to charge those small or low c celled packs.

For the record as of right now I plan on touring with 72v 60-80ah lipo.
So that'd be 5 hp's with the meanwell. That's 2,988 watts at 4.15v/cell! All for under 300 bucks!
And still at 2/3-1/2c charge.

What do you guys think?
Sound like a solid Idea?
Hmm I guess the only problem (now that I think about it) is where to plug it in?
How many outlets do you need to charge something at 3kw? :?

 

[kiwiev]

Hi guys

Not sure if this is off topic but couldn't I get 3 of these in series for 74.6 volts

http://www.ebay.com.au/itm/like/321640243768?limghlpsr=true&hlpht=true&ul_noapp=true&hlpv=2&ul_ref=http%253A%252F%252Frover.ebay.com%252Frover%252F1%252F705-139619-5960-0%252F2%253Fipn%253Dicep%2526icep_id%253D62%2526mtid%253D1797%2526kwid%253D1%2526crlp%253D40593704497_573061%2526icep_item_id%253D321640243768%2526itemid%253D321640243768%2526icep_meta_categ_id%253D170769%2526icep_etrs%253DN%2526icep_epid%253D-999%2526icep_ctlg%253D-999%2526icep_cond%253Dnew%2526targetid%253D78459360337%2526rpc%253D0.40%2526rpc_upld_id%253D53884%2526device%253Dt%2526icep_cbt%253Dn%2526icep_msku_flag%253Dn%2526adtype%253Dpla%2526loc%253D%2526poi%253D%2526campaignid%253D%2526adgroupid%253D%2526srcrot%253D705-139619-5960-0%2526rvr_id%253D889547478038&chn=ps&lpid=107&ops=true&viphx=1

Variable volts and amps

Cheers Kiwi

 

[Kin]

well err that's definitively off topic..

But if you are looking at that check out the weight and price (both are quite high.) You'd get a much more compact design through some of the other systems.

If you do want to use an adjustable lab supply like that (I say "lab" in quotes though since that looks like maybe a cheap imitation which I use all the time [generally cheap clones] but don't expect to act as nicely as real lab supplies.) there are better ways to use it. I would suggest finding a generic power supply with say 6A ability, and put that in series [if you know everything is appropriately isolated] with the 5A lab supply, so the lab supply regulates the current when it goes above 5A. It works so long as the situation of 0V output on the lab supply is sufficient to stop the current.

 

[kiwiev]

Thanks Kin

Server power supplies are not that cheap down here.

I may go and check out our local rubbish tip and see if I can get some or at least 6 old computer power supplies.

Cheers Kiwi

 

[Kin]

Thanks Kin

Server power supplies are not that cheap down here.

I may go and check out our local rubbish tip and see if I can get some or at least 6 old computer power supplies.

Cheers Kiwi

HI Kiwi! I did want to add a note: sorry about my harsh claim that this was off topic! A) It just came across a little harsh (just reread it) and by no means was that intended. B) I just realized that your comments aren't really off topic at all! I thought this was the thread for the 56V power supply for which very few people were talking about doing the series combinations, but in this thread that is the topic of consideration. Totally my fault.

If you want to use multiple lab power supplies in series (even in new zealand or australia I suspect they are pricier than your alternatives) I am not 100% sure how they will behave, but you should probably set one of the power supplies as the master controller, and the others as dumb-supplies. That is, perhaps 1 set to 4A so it will regulate at 4A, but the others at 5A. What you don't really want is a wave of all of them varying their individual output in some chaotic fashion.

I also note that I have no idea if you can connect the outputs in series without blowing something up. By the way, I think there are some threads about "BMSbatteries" and I think they have some standard chargers that might suite you if you're looking for a decent powerful charger at a price better than the lab supplies you showed me. It comes from china and you may want to review the endless-sphere threads because I don't know if they're still considered a shady-but-decent vendor or if they've gotten crappier.

 

[kiwiev]

No worries Kin

I have one of these units powering my solar panel tracker it has been running a year now continuously with no problems.
I have a BMS, charger already but need another one and our Aussie dollar is crap atm
So was looking for alternatives im not sure if the negative dc is tied to the AC earth on the Lab power supply will have to check.
I do like the idea of computer power supplies most I have seen are 12 volt at 17amps which would suit me fine.
I wish someone sold a simple voltage settable relay switch then I could run my 75 volt 25amp charger thru it and set volts for 74.7 volt for my 18s 30Ah pack.
Any thoughts Kin?

Cheers Kiwi

 

[Kin]

I'm not sure by your last comment: By "voltage resetable relay switch" Do you mean something that shuts off power after your pack reaches full voltage? I suspect for practical purposes it is not too important if your charger trickles a few mAh at the end of charge, just set your target voltage below absolute maxinum. And most chargers have an adjustment pot. There are definitively people who "bulk charge" their lipo using simple power supply units. The biggest thing is whether your charger simply shuts-off after over-current, or if it adjusts down the voltage until it is not over-current (as most meanwells that we use do.)

I guess I'm not totally clear what you were considering doing

 

[Ohbse]

Server PSU's are super cheap in NZ if you know people that work in large scale IT. I recycle pallet loads of servers quite regularly. If you're in NZ and have a desperate need for server PSU's hit me up. Not willing to take on international shipping sorry.

Worth stating for the wider knowledge base that there are many, many better options than these older HP units now available. The latest generation server power supplies are far more energy dense, far more efficient and just as reliable. The latest Lenovo units are physically 1/4 of the volume but power has increased to 900w+ with 94%+ efficiency.

As another alternative that didn't exist several years ago, there are a number of very compact, power dense front end rectifiers that output ~52v and 35 amps or even more. I have bought a few of these from ebay for ~$20USD and work great. Brands to look out for are Lineage power, Eaton, GE Critical power, Cherokee and Eltek Flatpack.

I have a number of PSU's from older IBM Bladecenter E's - these will do 12v and 225a all day long. Think I have 12 of them, so could get pretty crazy if required.

 

[kiwiev]

I'm not sure by your last comment: By "voltage resetable relay switch" Do you mean something that shuts off power after your pack reaches full voltage? I suspect for practical purposes it is not too important if your charger trickles a few mAh at the end of charge, just set your target voltage below absolute maxinum. And most chargers have an adjustment pot. There are definitively people who "bulk charge" their lipo using simple power supply units. The biggest thing is whether your charger simply shuts-off after over-current, or if it adjusts down the voltage until it is not over-current (as most meanwells that we use do.)

I guess I'm not totally clear what you were considering doing

The charger I have is for 24s Headways so its setup for that, I was thinking if I could plug in a limit voltage setting I could charge my Lipo 18S as well.

Sorry for the confusion :?

Cheers Kiwi

 

[kiwiev]

Server PSU's are super cheap in NZ if you know people that work in large scale IT. I recycle pallet loads of servers quite regularly. If you're in NZ and have a desperate need for server PSU's hit me up. Not willing to take on international shipping sorry.

Worth stating for the wider knowledge base that there are many, many better options than these older HP units now available. The latest generation server power supplies are far more energy dense, far more efficient and just as reliable. The latest Lenovo units are physically 1/4 of the volume but power has increased to 900w+ with 94%+ efficiency.

As another alternative that didn't exist several years ago, there are a number of very compact, power dense front end rectifiers that output ~52v and 35 amps or even more. I have bought a few of these from ebay for ~$20USD and work great. Brands to look out for are Lineage power, Eaton, GE Critical power, Cherokee and Eltek Flatpack.

I have a number of PSU's from older IBM Bladecenter E's - these will do 12v and 225a all day long. Think I have 12 of them, so could get pretty crazy if required.

Hey Mate how much do they weight roughly I have to come thru Auckland at the start of December over night both ways for my mother-in-law 80th.

Cheers Kiwi

 

[Ohbse]

Newer units are small, maybe 1.5kg each approximately.

If you're after big grunty ones they're probably a good 3.5kg each.

 

[andrew124C41]

I just purchased 2 of these off ebay for 25 bucks.
I understand they are more difficult to isolate than the 600s.
Mine looks a bit different in the back where the fan is.
There is no room to make the holes.
You can see pictures of them here: https://www.ebay.com/itm/302470991249?ul_noapp=true

I find the pictures here a bit hard to see in terms of finding out how to isolate the DC ground.

Any advice would be helpful.

Thanks.

 

[timmy66]

I've read thru this and other threads talking about stacking several 12V power supplies in series, and then adding a lab type power supply that's current limited.

I'm not sure I understand this really well --

the lab supply functions as the constant current part that will do the transition to constant voltage, when the total desired series voltage is met?

So if you were wanting to charge at say 54.6 V, you'd have 4 x 12v supplies, and then a 10a 12V CC/CV lab supply, and dial the lab into 6.6V, with a CC of 10A?

This is safe, reliable, charge output graphs look good, all that??

Thanks in advance for running through an example.

 

[999zip999]

I run one of these with a meanwell 24v 10amp set at 29v and to puts out 16amp. The hp is what 12.6v and 55amp. I use two of these for my 24s pack split in two for charging each 12s at 16amp. Only if you have cells that can handle it.