-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Friday 2008-06-27 at 19:12 -0600, Tom Patton wrote:
On Fri, 2008-06-27 at 20:12 +0200, Carlos E. R. wrote:
What I propose is:
PSU ____ / \ 48V DC --> +12V -12V +5V -5V 3?
Sorry to range off-topic, but here's my reasoning. I considered direct dc-dc conversion, but, also being a HAM, there is probability of RFI and even lightning entering the computer from the solar system/battery bank outside. Having a good commercial UPS already, I am replacing its batteries with my (soon-to-be) 48v stack, and the UPS will then function normally in response to the few hours a day we are on generator. The higher capacity solar-charged batteries will carry the system for the remainder of the day.
RFI can be blocked with chokes. Some (many?) DC-DC converters have in fact an AC stage, with a transformer, so there is galvanic isolation. Lightning... ufff!. Dunno. Best thing is a good l. rod. You know that bad lighning protection is worse that no protection? It atracts rays, which then find no easy route to earth, and use the house and equipment instead. Fire and disasters. I remember seeing some years ago a PC power supply that replaced the standard PSU, and had internal batteries, working as an UPS when the AC failed. Ie, it was a PSU/UPS unit in one, with one converter stage less, more efficient, which is something to consider when you are not on mains. There may exist commercial 12DC PSUs for computers, but probably the inverter road is more known/cheaper. There is a range of -48 V converters used in telephone exchange. They should be very expensive. And it is -48 because earth is the + line (dunno why, historical reasons, I suppose). All equipment designed for telephone exchange must use -48, but sometimes they are forced to use standard AC mains equipment with inverters. I have seen, for instance, Cisco routers fed from -48 directly.
The main system is (4) GNB Absolyte-IIP 440AH batteries in parallel for 12v. They supply two (phase-locked) inverters and 12v lighting circuits to the house. It would be slightly more efficient running the main at 48, but at the time the RV inverters were much less expensive than an industrial inverter. Being 12v also let me expand the solar panels as I went along, and allow for several "mobile" radios in the HAM shack.
A complex installation :-)
So I hope that answers the /tmp question!
Right, I changed the subject O:-) - -- Cheers, Carlos E. R. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) iD8DBQFIZhrVtTMYHG2NR9URAnfRAJ4yMyFL7UUl+EZGJrqVowkdZSjSMQCfbPOu QC3qM1eq8uioeCRLfrqsv8o= =UPvp -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org