Charger and PS question

[boogie12]

I have a Hitec charger that can take 12-18v max and I have 2 power supplies one of them is already modified and putting out 12v. I want modify the other supply to put out 12v also and wire the two together to get 24v.

My question is will my charger be able to handle 24 volts safely or will I need to step down the voltage to something more in line with the chargers max input voltage? I see inside the power supply that I have a 3.3 volt line and a 5 volt line. If I wire the 5 volt rail of PS2 with the 12 volt rail of PS1 I can get 17v if I wire it in series right?

[Smoggie]

Sorry, but there is no way to get 18V out of two 12V PSU's, it'e either 12V or 24V. The PSU's will have trimmers inside that allow a very limited voltage adjustment, but not enough to get down to 18V.

The 5V rail on the PSU is low power only, nowhere near enough amps for your purpose.

[Jazzjohn]

Yes, you can wire the 5v from one supply in series with the 12v from the other to get 17v as long as the both supplies' outputs are isolated from chassis ground.
The output with the lower current capacity (usually the 12v output for a PC PS) will determine the maximum output current.

[Coolice]

Originally Posted by Jazzjohn

Yes, you can wire the 5v from one supply in series with the 12v from the other to get 17v as long as the both supplies' outputs are isolated from chassis ground.
The output with the lower current capacity (usually the 12v output for a PC PS) will determine the maximum output current.

Hey Buddy.

No you can't, as said above your post, if you read the small print on the PSU's the 5 volt output is only a few amps and no where near the amp capability of the main 12 volt rail. So you will blow the output stage on the PSU you're trying to use for a 5 volt supply.
As an example the DPS-600PB's 5 volt output is only rated to 7 amps, 40 amps short of the main output points.

You're best option is to grab a PSU which with modifications, can then be turned up to 15 volts or more. The Dell 6650 I think can be off the top of my head, although a larger unit in terms of size, it can go to 15~16 volts output easy.

Ian

[boogie12]

Well it has been a while since I checked this thread and you guys are correct the supplies can't be wired together for 17v. I was experimenting with the two supplies and I managed to get a 17v output from the two supplies but it was short lived,the supply that was putting out 5v died a week after use.

I should have checked back into this thread before I did it though.

[Smoggie]

Oh well, at least you proved the theory to be correct

[Coolice]

Hey Buddy.

Sorry to hear you fried a PSU, but on the other hand it has answered the question fully by actually trying it.

It would be handy, but the 5V AUX lines on the PSU's are only there to provide input to small drain items within the servers.

Ian