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| Thread ID: 32581 | 2003-04-23 03:10:00 | Cheap UPS | somebody (208) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 138042 | 2003-04-24 01:17:00 | The biggest problem is amps. If your desktop takes only 230W (and assuming it has a PF of 1 (!) ) that takes 1 A at 230V AC. To make that 230 W at 230V with an inverter will take at least 20A DC from your 12V battery. A less efficient inverter, and a lower power factor of the computer makes it worse. On the basis that you want a UPS for continuous normal use, your "charger" has to supply that current, plus a trickle charge for the battery. After a power failure, and your orderly shutdown of the computer, the power comes on again some time later. Now the charger has to replace the energy which has been taken from the battery, plus the computer drain. This is not a $40 car battery charger. :D That's why most commercial UPS boxes pass through mains power to the computer, and keep the battery on trickle charge. If the power fails, there is a very quick changeover to the inverter inside the UPS. As long as this happens in less than a few tens of milliseconds, the computer never notices. Big "no-break" systems have a mains motor driving a flywheel and an alternator. On the other end of the shaft is a diesel engine. If the mains fails, the diesel will usually start before the flywheel slows too much. Pedal power is limited. Us "normal" people should be able to keep up 100W for a reasonable time. It takes special training of very special people to pedal Gossamer Condor, etc. You can buy 80W solar panels for $999. The average sunshine hours/day is 5. Sometimes the sun doesn't shine. Wind power is a possibility. If you can get permission to build a 30m tower with a 3-5m spinner on top. You neighbours might object. :D The most economic is a home methane generator and an engine driven alternator. You could feed the methane generator with BS from the Internet. :D |
Graham L (2) | ||
| 138043 | 2003-04-24 09:12:00 | What sites would you suggest, Graham, as the most efficient generators of BS? Maybe the bicycle seat could be replaced with a WC one to augment the methane supply from the net. That'ed be a lot of beans and saurkraut though, wouldn't it? Telemarketing firms could save a bit on their power bill with the right setup :) Murray P |
Murray P (44) | ||
| 138044 | 2003-04-24 22:52:00 | Solar generation could be supplemented during evening hours by connecting to the telephone to harness the considerable BS energy from telemarketers. It makes me cringe how much generation opportunity is going to waste at the moment. And when the telemarketers are having a rare break you can hook the generator up to the TV. Like E.ric keeps telling us there is so much BS on these days it is no wonder we all need these UPS things in the first place. :-) |
Susan B (19) | ||
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