Re: recycling chargers
On Wed, May 12, 2010 at 05:31:57PM -0400, Raul Gutierrez Segales wrote: > Created by the local techs of our deployment in Caacup??: > http://oficina.paraguayeduca.org/~rgs/multiple-chargers/ Neat. An ATX or AT switch-mode power supply attached to a set of nine laptop charging cables. The power supply is being used as a 12V DC regulated source. The original PC power harness cables have been removed. I suggest that to increase the lifetime of the cables, they be wrapped with electrical insulating tape at the point they exit the power supply, and anchored to the chassis of the power supply with a nylon wire tie. -- James Cameron http://quozl.linux.org.au/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
On Thu, May 13, 2010 at 06:44:34PM +1000, James Cameron wrote: An ATX or AT switch-mode power supply attached to a set of nine laptop charging cables. The power supply is being used as a 12V DC regulated source. The original PC power harness cables have been removed. FWIW, I've also used a ATX power supply to power an XO-1, but stopped doing so once I discovered why the XO-1.5 would run from it: Being a cheap model, it regulated only the 5V rail, so the 12V rail dropped down to 9V with a switched-on XO-1 connected to it. The XO-1 barely coped (the power light started flickering some time ago, probably due to the power supply aging and delivering an even lower voltage than before) and the XO-1.5 (without MPPT ECO) didn't like it at all (whining noise, LED off). Summary: If you're trying to replicate this setup, make sure your PC power supply regulates the 12V rail (just hook up some load and check the voltage). CU Sascha -- http://sascha.silbe.org/ http://www.infra-silbe.de/ signature.asc Description: Digital signature ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
That is probably a wrong analysis of the problem. Many higher power supplies like AT/ATX power supplies don't work properly when unloaded. I bet if you draw a couple of amps from the +5V supply, you would find that the +12V supply starts working fine. I used to use car headlights to provide enough load when debugging systems which weren't loaded enough to maintain regulation. Cheers, wad On May 13, 2010, at 5:43 AM, Sascha Silbe wrote: > On Thu, May 13, 2010 at 06:44:34PM +1000, James Cameron wrote: > >> An ATX or AT switch-mode power supply attached to a set of nine laptop >> charging cables. The power supply is being used as a 12V DC regulated >> source. The original PC power harness cables have been removed. > FWIW, I've also used a ATX power supply to power an XO-1, but stopped doing > so once I discovered why the XO-1.5 would run from it: Being a cheap model, > it regulated only the 5V rail, so the 12V rail dropped down to 9V with a > switched-on XO-1 connected to it. The XO-1 barely coped (the power light > started flickering some time ago, probably due to the power supply aging and > delivering an even lower voltage than before) and the XO-1.5 (without MPPT > ECO) didn't like it at all (whining noise, LED off). > > Summary: If you're trying to replicate this setup, make sure your PC power > supply regulates the 12V rail (just hook up some load and check the voltage). > > CU Sascha > > -- > http://sascha.silbe.org/ > http://www.infra-silbe.de/___ > Devel mailing list > Devel@lists.laptop.org > http://lists.laptop.org/listinfo/devel ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
We did this in Uruguay. It's difficult to ensure proper regulation on the 12V rail. You have to have a proper load to ensure stability. A good power supply of course helps. To improve this you can put a resistor in the 5V rail. Of course it wastes some power and the heat is a concern if it's enclosed. But we tried it and it worked fine with only the power supply fan. Ismael 2010/5/13 Sascha Silbe > On Thu, May 13, 2010 at 06:44:34PM +1000, James Cameron wrote: > > An ATX or AT switch-mode power supply attached to a set of nine laptop >> charging cables. The power supply is being used as a 12V DC regulated >> source. The original PC power harness cables have been removed. >> > FWIW, I've also used a ATX power supply to power an XO-1, but stopped doing > so once I discovered why the XO-1.5 would run from it: Being a cheap model, > it regulated only the 5V rail, so the 12V rail dropped down to 9V with a > switched-on XO-1 connected to it. The XO-1 barely coped (the power light > started flickering some time ago, probably due to the power supply aging and > delivering an even lower voltage than before) and the XO-1.5 (without MPPT > ECO) didn't like it at all (whining noise, LED off). > > Summary: If you're trying to replicate this setup, make sure your PC power > supply regulates the 12V rail (just hook up some load and check the > voltage). > > CU Sascha > > -- > http://sascha.silbe.org/ > http://www.infra-silbe.de/ > -BEGIN PGP SIGNATURE- > Version: GnuPG v1.4.10 (GNU/Linux) > > iQEcBAEBCgAGBQJL68nFAAoJELpz82VMF3DahUEH/A2cg/SpM9edBRh80iBQ02cU > 5UYmYbEFk1k+SIc5zq/z9LfvUZC3oE5o+UNhbI22zoB8fot7mJ7gxqo+wOzYdi2v > 0OI7BPeU4rkqmApGYWlWXiqiQQeNjm862a+R+V1rBUkwP8rgzzp0Dhq4WYhNiXr1 > gKBfXARVhdXAJggyIGtDMcltiVEI/EJbOgfhZO94F8786H1rgQ1H2C80rSclympj > mrkGRX2p0c7lCohiyW1jNkVhFpQeivuzh0v2nHgN/p3CYtUPHR2qABEotHG61h2t > cWt2oDCTYFzDiW9KwIrrSTHxNDHNZgoDZwKZbi56wo1uc6Fhi/D3ayyXjcmkdqQ= > =ta5+ > -END PGP SIGNATURE- > > ___ > Devel mailing list > Devel@lists.laptop.org > http://lists.laptop.org/listinfo/devel > > -- Ismael Schinca Plan Ceibal - Depto. Técnico - I+D Avda. Italia 6201 Montevideo - Uruguay. Tel.: 601 57 73 Int. 2227 E-mail : ischi...@plan.ceibal.edu.uy ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
Exactly, some load in the 5V rail is needed. We managed to charge up to 20 XO using a single 680W power supply. In any case, the total power of the supply is not important, you must check the 12V rail current rating (and estimate approx 1.5A per XO). Also, some power supplies have more than 1 12V rail. You must take this into account. You can be sure that the CPU connector and the PCI-X connector for the VGA will always have separate rails as those are the bigger power draws in a PC. Ismael 2010/5/13 John Watlington > > That is probably a wrong analysis of the problem. > Many higher power supplies like AT/ATX power supplies don't > work properly when unloaded. I bet if you draw a couple of > amps from the +5V supply, you would find that the +12V supply > starts working fine. > > I used to use car headlights to provide enough load when > debugging systems which weren't loaded enough to maintain > regulation. > > Cheers, > wad > > On May 13, 2010, at 5:43 AM, Sascha Silbe wrote: > > > On Thu, May 13, 2010 at 06:44:34PM +1000, James Cameron wrote: > > > >> An ATX or AT switch-mode power supply attached to a set of nine laptop > >> charging cables. The power supply is being used as a 12V DC regulated > >> source. The original PC power harness cables have been removed. > > FWIW, I've also used a ATX power supply to power an XO-1, but stopped > doing so once I discovered why the XO-1.5 would run from it: Being a cheap > model, it regulated only the 5V rail, so the 12V rail dropped down to 9V > with a switched-on XO-1 connected to it. The XO-1 barely coped (the power > light started flickering some time ago, probably due to the power supply > aging and delivering an even lower voltage than before) and the XO-1.5 > (without MPPT ECO) didn't like it at all (whining noise, LED off). > > > > Summary: If you're trying to replicate this setup, make sure your PC > power supply regulates the 12V rail (just hook up some load and check the > voltage). > > > > CU Sascha > > > > -- > > http://sascha.silbe.org/ > > > http://www.infra-silbe.de/___ > > Devel mailing list > > Devel@lists.laptop.org > > http://lists.laptop.org/listinfo/devel > > ___ > Devel mailing list > Devel@lists.laptop.org > http://lists.laptop.org/listinfo/devel > -- Ismael Schinca Plan Ceibal - Depto. Técnico - I+D Avda. Italia 6201 Montevideo - Uruguay. Tel.: 601 57 73 Int. 2227 E-mail : ischi...@plan.ceibal.edu.uy ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
On Thu, May 13, 2010 at 09:24:17AM -0400, John Watlington wrote: FWIW, I've also used a ATX power supply to power an XO-1, but stopped doing so once I discovered why the XO-1.5 would run from it: Being a cheap model, it regulated only the 5V rail, so the 12V rail dropped down to 9V with a switched-on XO-1 connected to it. The XO-1 barely coped (the power light started flickering some time ago, probably due to the power supply aging and delivering an even lower voltage than before) and the XO-1.5 (without MPPT ECO) didn't like it at all (whining noise, LED off). Summary: If you're trying to replicate this setup, make sure your PC power supply regulates the 12V rail (just hook up some load and check the voltage). Many higher power supplies like AT/ATX power supplies don't work properly when unloaded. I bet if you draw a couple of amps from the +5V supply, you would find that the +12V supply starts working fine. In what way is that different from what I wrote? Or are you saying that once I draw a certain amount of current from the 5V rail, the 12V one will be properly regulated (i.e. keeping the voltage stable at 12V +/- 10% regardless of the current draw on the 12V rail)? CU Sascha -- http://sascha.silbe.org/ http://www.infra-silbe.de/ signature.asc Description: Digital signature ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
On May 13, 2010, at 10:18 AM, Sascha Silbe wrote: > On Thu, May 13, 2010 at 09:24:17AM -0400, John Watlington wrote: > >>> FWIW, I've also used a ATX power supply to power an XO-1, but stopped doing >>> so once I discovered why the XO-1.5 would run from it: Being a cheap model, >>> it regulated only the 5V rail, so the 12V rail dropped down to 9V with a >>> switched-on XO-1 connected to it. The XO-1 barely coped (the power light >>> started flickering some time ago, probably due to the power supply aging >>> and delivering an even lower voltage than before) and the XO-1.5 (without >>> MPPT ECO) didn't like it at all (whining noise, LED off). >>> >>> Summary: If you're trying to replicate this setup, make sure your PC power >>> supply regulates the 12V rail (just hook up some load and check the >>> voltage). > >> Many higher power supplies like AT/ATX power supplies don't >> work properly when unloaded. I bet if you draw a couple of >> amps from the +5V supply, you would find that the +12V supply >> starts working fine. > In what way is that different from what I wrote? Or are you saying that once > I draw a certain amount of current from the 5V rail, the 12V one will be > properly regulated (i.e. keeping the voltage stable at 12V +/- 10% regardless > of the current draw on the 12V rail)? Your latter statement is correct. There is usually a "main rail" (+5V or +3.3V) which must be loaded for the "auxiliary rails" (+12V) to be regulated. Cheers, wad ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: recycling chargers
Sascha, that's correct, once the 5V rail is loaded the 12V rail is properly (properly depending on the power supply quality) regulated. Apparently, switched power supplies need a proper load to correctly regulate voltage. You may try something like 1A in the 5V rail. Be sure to use a resistor which can tolerate 5W (4,7ohm, 9W for example) ! Ismael 2010/5/13 Sascha Silbe > On Thu, May 13, 2010 at 09:24:17AM -0400, John Watlington wrote: > > FWIW, I've also used a ATX power supply to power an XO-1, but stopped >>> doing so once I discovered why the XO-1.5 would run from it: Being a cheap >>> model, it regulated only the 5V rail, so the 12V rail dropped down to 9V >>> with a switched-on XO-1 connected to it. The XO-1 barely coped (the power >>> light started flickering some time ago, probably due to the power supply >>> aging and delivering an even lower voltage than before) and the XO-1.5 >>> (without MPPT ECO) didn't like it at all (whining noise, LED off). >>> >>> Summary: If you're trying to replicate this setup, make sure your PC >>> power supply regulates the 12V rail (just hook up some load and check the >>> voltage). >>> >> > Many higher power supplies like AT/ATX power supplies don't >> work properly when unloaded. I bet if you draw a couple of >> amps from the +5V supply, you would find that the +12V supply >> starts working fine. >> > In what way is that different from what I wrote? Or are you saying that > once I draw a certain amount of current from the 5V rail, the 12V one will > be properly regulated (i.e. keeping the voltage stable at 12V +/- 10% > regardless of the current draw on the 12V rail)? > > > > CU Sascha > > -- > http://sascha.silbe.org/ > http://www.infra-silbe.de/ > > -BEGIN PGP SIGNATURE- > Version: GnuPG v1.4.10 (GNU/Linux) > > iQEcBAEBCgAGBQJL7ApLAAoJELpz82VMF3DacX4H+wdaJccvnIKGh8+7CvdAeQnQ > FuhShcjiM3h6MzZTPxLXH4KjDm8upzGCtPJlNLGl9izL+MPizGdebiufMRujeouH > ZZk3Da/RhtIsugKPKYLVBuXo2bGX6vG4Jsm4VExRHWxQjS8WBV6UTW2iYMOkOjt4 > Awb78u/K9A/WoS6L2Az/ZTRvs1VHiprdWoMtGtLJA13FJ5LZaixuTmWk14ZCAMRK > NdGM3sD36PJzUlHejDDJADxWeLhLnkbbLDaf+AbS3rQYGpTbNnVEh80yiWRKYTkp > JYc5YMAjsXyKelMmVJaiQRfea2juJ3rUALn/rq1F4xL74rVSm273D5dxVS3tbbU= > =QlEW > -END PGP SIGNATURE- > > ___ > Devel mailing list > Devel@lists.laptop.org > http://lists.laptop.org/listinfo/devel > > -- Ismael Schinca Plan Ceibal - Depto. Técnico - I+D Avda. Italia 6201 Montevideo - Uruguay. Tel.: 601 57 73 Int. 2227 E-mail : ischi...@plan.ceibal.edu.uy ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
