PC Power Supply Troubles

[sanyijr]

Simple question I hope....

I have a charger and am charging 2 Lipo 5000 mah batteries in parallel at 10 amps total. See simple.

My PC supply is lower rated but still states 250 watts. So at 12 Volts, should deliver 250/12 or 20.8333 amps (less efficiency) for charging capacity.

But still voltage is dropping too low so I can only charge at 8 amps total as voltage hovers around 10.65v. Charger is cool, so heat is no issue.

Has anyone actually added a resistor bar or other form of current draw on the 5 Volt bar to increase Voltage? Does this work? Worth doing? Any other suggestions?

Since I just dropped over $300 on batts and charger (Hyperion 720 duo ) I am not buying a power supply....yet! And looking for possibly a simple solution to my simple question...

Thanks

[kookie_guy]

Simple question I hope....

I have a charger and am charging 2 Lipo 5000 mah batteries in parallel at 10 amps total. See simple.

My PC supply is lower rated but still states 250 watts. So at 12 Volts, should deliver 250/12 or 20.8333 amps (less efficiency) for charging capacity.

But still voltage is dropping too low so I can only charge at 8 amps total as voltage hovers around 10.65v. Charger is cool, so heat is no issue.

Has anyone actually added a resistor bar or other form of current draw on the 5 Volt bar to increase Voltage? Does this work? Worth doing? Any other suggestions?

Since I just dropped over $300 on batts and charger (Hyperion 720 duo ) I am not buying a power supply....yet! And looking for possibly a simple solution to my simple question...

Thanks

The 12v tap on a 250w PC power supply is typically only rated to 10A. The 250w is the TOTAL rating, of all the taps combined.

Time to pick up one of these from the US warehouse when they are back in stock.
http://www.hobbyking.com/hobbyking/s...dProduct=13416

[GP73]

Why? You can buy a 47A 12V PS for $50 here: http://www.feathermerchantrc.com/

Not as fancy as HK, but way more reliable IMO: these are HP enterprise-level power supply for servers, designed to run 24/7.

[Alexgar]

I use laptop power supplies I bought from goodwill computers 1 12v 5a for 5$ and a 17v 8a for 10$ that way I hard wire 1psu per charger

[kookie_guy]

Why? You can buy a 47A 12V PS for $50 here: http://www.feathermerchantrc.com/

Not as fancy as HK, but way more reliable IMO: these are HP enterprise-level power supply for servers, designed to run 24/7.

nice, I was not aware of those.

[HYDROJERRY]

I went to TigerDirect today and got a PC power supply for 19.99 its 400w,,, i just tryed to do a 250w Dell and blew it up so im going to try again this time fallowing the directions closely!!!

[sanyijr]

But as kookie_guy stated, if the 12 volt bar is limited at 10 amps, WTF! Total wattage is worthless.....for this application then

kookie_guy, is that for all PC power, being limited to 10A or is it some fraction of the total on the 12V bar? Do you know the reasoning behind that 10A? Would it be safe to say that a 500W PC have 20amp capacity before voltage drops off? What dictates the amount of voltage drop? Would a 1000W have less voltage drop?

Such a simple question...... How did it get so complicated (I know, because I am trying to cut corners.... Scissors please!!!!!......I'm not even Drewish, who knew)

[sanyijr]

So I pulled this off the Tigerdirect website.... Would it be safe to say that if I tied 12V-1 and 12V-2 in parallel, I could theoretically pull 36 amps sustained at 12V +/-?

If my PS has 2-12V bars. Same idea.....Maybe?

Cooler Master 500W PSU Extreme Power Plus Form Factor: ATX
Wattage: 500W
Fan: 120 mm
+3.3V: 22 A
+5V: 25 A
+12V 1: 18 A
+12V 2: 18 A
-12V: 0.5 A
+5VSB: 2.5 A
20+4-Pin Connector: 1
4-Pin/8-Pin EPS Connector: 1
6-Pin PCI-Express Connector: 1
4-Pin Floppy Connector: 1
4-Pin Peripheral Connector: 5
SATA Power Connector: 4

[GP73]

As I said above, 47A. One rail.

With those server PSU you get all the wattage on a single rail, nothing comes close, unless you spend thousands of dollars for a LAB PSU.

Do yourself a favour and buy one (or two)

[sanyijr]

GP73, you made me laugh. Too funny. So what you mean to say is S.T.F.U and get a SPS from http://www.feathermerchantrc.com already.

Will do.... Next month when the credit casrd clears for my Hyperion eos720 duo and the 2 5000 mah lipos.

Until then, I will charge at 8 amps and deal with it.........

Everyone has been very helpful. Thanks!

[GP73]

Another small advice: if noise is a concern then get the 42A ones, they have thermal control and variable speed fans if I recall correctly (ask the guy that sells them, he's very good)

The 47A is very noisy, especially if you have 2 running at the same time.

GP73, you made me laugh. Too funny. So what you mean to say is S.T.F.U and get a SPS from http://www.feathermerchantrc.com already.

Will do.... Next month when the credit casrd clears for my Hyperion eos720 duo and the 2 5000 mah lipos.

Until then, I will charge at 8 amps and deal with it.........

Everyone has been very helpful. Thanks!

[sanyijr]

Another small advice: if noise is a concern then get the 42A ones, they have thermal control and variable speed fans if I recall correctly (ask the guy that sells them, he's very good)

The 47A is very noisy, especially if you have 2 running at the same time.

That leads me to another question then.... What is the difference between the 47A and the 42A? Besides the obvious 5A. Why offer both if no cost impact?

[GP73]

I think he offers the 42A because they have the thermal control feature, otherwise if you don't care about the noise pick the 47A.

There are few threads dedicated to these PSU on RCgroups, including how to connect 2 of them to get 24V (and also connect 4 to get 24V @ 94A total!!!).

[egneg]

I converted one of these for my power supply ... I think I have about $25.00 total into it as I got it with some other stuff I ordered.

http://3btech.net/ch550wadufan.html