EE help? 2 13.8V power supplies in series?

jaydee · 04-09-2005, 02:01 PM

Ok, I got 2 13.8V 15amp identical power supplies from Radio Shack this morning. What I want to do is put them in series to get 27.6V

What do I need to do?

Following this article http://www.procooling.com/articles/h...chnology_-.php I need to unhook the ground to the chassis on one of the supplies. I popped open one unit and it is grounded to the chassis.

Here are some pics.

---

It is grounded through that green wire in the back. I am not sure though if that is what also grounds the 4 mounting holes? Should I make it to were there is no metal contacting the chassis?

jaydee · 04-09-2005, 03:32 PM

Well never mind. I am an impatient bastard today and figured today is as good as any to fry a $70 power supply. I unhooked the green ground from the AC plug and electrical tapped the standoffs the PCB mounts to. I connected the positive from the modded unit to the heater cartridge, the negative of the modded unit to the positive of the second un-modded supply and the ground from the un-modded supply to the heater cartridge.

What happened? DMM says 28volts and the die sim is one hot bitch. Seems to have worked!

So if my calculations are correct the Die sim should have a 73watt heat load.

Heater cartridge is 10.7ohm's divide 28v = 2.6amp x 28 = 73.27 watts.

04-09-2005, 02:01 PM	#1
jaydee Put up or Shut Up Join Date: Dec 2001 Location: Spokane WA Posts: 6,506	EE help? 2 13.8V power supplies in series? Ok, I got 2 13.8V 15amp identical power supplies from Radio Shack this morning. What I want to do is put them in series to get 27.6V What do I need to do? Following this article http://www.procooling.com/articles/h...chnology_-.php I need to unhook the ground to the chassis on one of the supplies. I popped open one unit and it is grounded to the chassis. Here are some pics. --- It is grounded through that green wire in the back. I am not sure though if that is what also grounds the 4 mounting holes? Should I make it to were there is no metal contacting the chassis?

04-09-2005, 03:32 PM	#2
jaydee Put up or Shut Up Join Date: Dec 2001 Location: Spokane WA Posts: 6,506	Well never mind. I am an impatient bastard today and figured today is as good as any to fry a $70 power supply. I unhooked the green ground from the AC plug and electrical tapped the standoffs the PCB mounts to. I connected the positive from the modded unit to the heater cartridge, the negative of the modded unit to the positive of the second un-modded supply and the ground from the un-modded supply to the heater cartridge. What happened? DMM says 28volts and the die sim is one hot bitch. Seems to have worked! So if my calculations are correct the Die sim should have a 73watt heat load. Heater cartridge is 10.7ohm's divide 28v = 2.6amp x 28 = 73.27 watts. Last edited by jaydee116; 04-09-2005 at 03:43 PM.

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