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NiHaoMike · 10-02-2009, 08:42 PM

Converting from 120v to 12v and back to 120v is not very efficient. Build your own UPS from a power inverter and an ATX power supply with active PFC. Find the B+ rail (and its ground) in the inverter and connect it to the ATX power supply right after the input rectifier through a diode. Then add two 470uF or more 200v capacitors to the input circuit to make it a voltage doubler. (If 240v or 208v input, use only one 330uF or more 400v capacitor from B+ to B-.) Finally, keep the battery on float charge at 13.8v.

If you have an ATX power supply that accepts 12v from a wall wart (such as the PicoPSU), it is even easier. Same for most network equipment, which often operate from 12v. Just keep the battery at 13.8v with a float charger that outputs more than all the loads.

10-02-2009, 08:42 PM	#11 (permalink)
NiHaoMike Master EcoModder Join Date: Sep 2008 Location: Texas Posts: 632 Thanks: 0 Thanked 26 Times in 24 Posts	Converting from 120v to 12v and back to 120v is not very efficient. Build your own UPS from a power inverter and an ATX power supply with active PFC. Find the B+ rail (and its ground) in the inverter and connect it to the ATX power supply right after the input rectifier through a diode. Then add two 470uF or more 200v capacitors to the input circuit to make it a voltage doubler. (If 240v or 208v input, use only one 330uF or more 400v capacitor from B+ to B-.) Finally, keep the battery on float charge at 13.8v. If you have an ATX power supply that accepts 12v from a wall wart (such as the PicoPSU), it is even easier. Same for most network equipment, which often operate from 12v. Just keep the battery at 13.8v with a float charger that outputs more than all the loads. __________________ If America manages to eliminate obesity, we would save as much fuel as if every American were to stop driving for three days every year. To be slender like Tiffany Yep is to be a real hypermiler... Allie Moore and I have a combined carbon footprint much smaller than that of one average American...