Need Advice to incorporate PS in charging solution

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Robert Baumer

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May 6, 2017
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My days of overclocking and liquid cooling my PC is over, the powerwall project seems to be a more fruitful. I have since moved to dual hex core MACs for all my computer needs, fusion is awesome to run Windows 10 if you need it.....

Anyhow, back to my issue... I just pulled my power supply from one of my systems and want to make use of it in my 18650 charging. It looks like this one PS should cover all my needs. First I have begun gathering the parts I need to build Dan's OPUS charging station which uses 30a @ 12v. Since I still have a balance of 90a I was thinking of 90 TP4056 unless someone else has better suggestion.

All I know is this battery harvesting is taking a long time.

I am thinking of using a breakout adapter to wire the system like this

http://www.ebay.com/itm/24Pins-ATX-...411616?hash=item1ec3778fe0:g:-xwAAOSwCU1Yyt87



image_dzgiqe.jpg
 

Korishan

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You "could" use that. However, it has limitations. And, I think, you would go beyond the limitations of the breakout before you get anywhere near the limits of the PSU.

The reason why I saw this is because the wires coming from the ATX connector are thinner than the wires coming from the Molex connectors. The breakout only uses 1 or 2 of those wires, which severely limits your amp throughput.

My recommendation would be to A) open your PSU up, take all your red wires and resolder a heavier gauge in that location B) take all your molex connections and splice all the Red wires together into a common rail.
The same with the black and yellow wires. This will give you plenty of amperage throughput on all your voltages.

There's plenty of Youtube videos showing how to convert a PSU into a stand alone bench powersupply. To power the PSU w/o a motherboard, you only need to connect the green to ground on the ATX connector (dont recal pin number right now)

That's my thoughts on it, anyways :p btw, nice PSU for this project!!
 

Robert Baumer

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May 6, 2017
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Korishan said:
You "could" use that. However, it has limitations. And, I think, you would go beyond the limitations of the breakout before you get anywhere near the limits of the PSU.

The reason why I saw this is because the wires coming from the ATX connector are thinner than the wires coming from the Molex connectors. The breakout only uses 1 or 2 of those wires, which severely limits your amp throughput.

My recommendation would be to A) open your PSU up, take all your red wires and resolder a heavier gauge in that location B) take all your molex connections and splice all the Red wires together into a common rail.
The same with the black and yellow wires. This will give you plenty of amperage throughput on all your voltages.

There's plenty of Youtube videos showing how to convert a PSU into a stand alone bench powersupply. To power the PSU w/o a motherboard, you only need to connect the green to ground on the ATX connector (dont recal pin number right now)

That's my thoughts on it, anyways :p btw, nice PSU for this project!!

Thank Korishan, I will take some time to review all the youtube videos and come up with a plan, I may not have to tear it apart as there are so many modular connectors I can use.
image_duokfd.jpg
It came with a a lot of additional cables. But you have provided me things to think about, while I might have the amperage, I certainly have to consider the cable I am pushing it through.
 

Scepterr

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Feb 19, 2017
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Hey Robert, 12V 50A power supplies are like $30-40.5V50A power supplies are $20-$30I would just get one or 2 of those instead of cannibalising such a nice PSU
 

egam

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Mar 9, 2017
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I just combined some of the wires together to give the appropriate wire gauge for the load.

Don't forget to combine enough grounds together as well.

I did not open up the psu.

20 gauge is 11 amps max, 18 gauge is 16 amps max.

Not sure if the wiring is 20 or 18 so I combined all of the available wires of a common voltage together.
 

Robert Baumer

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May 6, 2017
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Does anyone have a gauge calculator? The power supplies main cable that would typically plug into the computer main board has an 16, 18, and 22 awg +12v, so if I combine them what should I come up with?
 

jdeadman

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Mar 28, 2017
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Most of the internal cabling in every PSU I have opened (a lot) are 16 or 14 guage. The bigger the PSU the bigger the wires. I have taken a PSU and used both the 5v rail and both 12v rails to charge my 18650s and the rating on the PSU for the 5v rail is way under what it can handle. The one I use now is labeled as 5v @5 amps and both 12v rails are 20a. I run 8 tp4056's and 4 of the 2 resistor dischargers (I forget the model but popular) as well my 2 Hyperion RC chargers (for discharging only on the 12v rails) without any issues. I have read about 10A on the 5v rail with out any issues
 

Korishan

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You are essentially doubling. So, if you look at a wire gauge chart, look for the combined amperage

18 awg can handle 10 amps. So, if you have 2x18, which is 2 * 10 = 20 Amps, then that would be equivalent to 12 awg (23 amp rating)


image_tnagsn.jpg
 

Robert Baumer

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Korishan said:
You are essentially doubling. So, if you look at a wire gauge chart, look for the combined amperage

18 awg can handle 10 amps. So, if you have 2x18, which is 2 * 10 = 20 Amps, then that would be equivalent to 12 awg (23 amp rating)


image_tnagsn.jpg

Thank you for providing me so much information. I am not going to tear the PS apart, but rather use a breakout box from eBay to separate out the 3.3v, 5v, and 12v. I am not sure to what extent I will use them as I am thinking of pulling from the other modular connectors. Each modular connector has 4 16 awg cables which should be sufficient for Dan's OPUS project. I believe that should provide me with 52amps per module.
 

Korishan

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What you could do is see if the square molex connectors will connect to the PSU ports. I've never had a modular PSU before, so I don't know how interchangeable they are.

Or, you could just cut the molex connectors off and just solder all the same color wires together and then go from there. Or get some old Harddrives/CDDrives/etc and pull their power ports out and solder them onto a new mount and just plug the molex into those (it would keep your modular wires in tact and give the flexibility of mobility)

As I mentioned before, the problem with the breakout board is it doesn't supply the full current capable of the PSU.
 

neilmc

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May 22, 2017
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Not a direct answer to what you're doing Robert, but I've spent some time in the LiPo drone racing world and high output DC supplies area thing that people are chasing for charginghigh C 1300mah to 1800mah packs. Some of these batterieswill charge at 5C+ comfortably and some peopleare charging 5-6 at a time in parallel. (they're bulky for their capacity, but some 1300mah 4Spacks can sustain 50A +discharge)

For those looking for a cheap high current DC power supply, there's a gold mine in server power supplies out there.

Typically the slide in cartridge type redundant supplies. The mod to get them to start outside of a server varies, but there's plenty of info in the RC hobby world. Consumer PC power supplies tend to greatly exaggerate their wattage (though Robert's is probably capable of veryhigh output).

I had a Thermaltake 800w which from memory quoted 18amp12 V. I took heavywires from the 12v rails and it topped out at about 11amp.

I pulled a relatively compact supply out of an old Dell server at work and it had no trouble delivering 20A 12vvia a 400w RC charger. (the max the charger supports for 1S). Apparently many of them can deliver 50A +and are relatively cheap on eBay for older models (around $50).

They tend to have large spring contacts on the end of them. I only had to join 2 each large negative and positive contacts to some heavy cable to get the max potential out of the supply.

Edit.... link to a thread in one of the RC hobby groups

https://www.rcgroups.com/forums/showthread.php?1292514-How-to-convert-Server-Power-Supplies

Edit 2... holy crap. Followed some RC stuff to one of the popular supplies. These HP supplies will deliver 100A 12V. Heavy connectors on the end, so easy to wire.

https://www.rcgroups.com/forums/sho...12Volt-100Amp-Power-Supply-Part1#post11639297
 

daromer

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I have several of them at home on the bench. All from 60A to 100+A at 12v. I fly drones too and use that types of chargers. You get a PSU for around 30EUR and they are made to only use 12v rail compare to atx and other normal psus to home computers that in general need to have something hooked up to the other rails to work 100%
 
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