On Saturday 23 October 2021 22:00:42 piorunz wrote: > On 17/10/2021 17:18, Gene Heskett wrote: > > The local electrical system, while better than Haiti's is getting to > > be a nuisance with 5 second power failures about weekly, or is that > > weakly? (...) > > I made some mods to a 3d printer project in openscad last week, > > printed it, but forgot to save it. So I lost it when the latest > > failure rebooted that machine. > > With all due respect, you should know that UPS to power up one > computer for an hour cost £150 on eBay, or even £70 if you can buy > used and/or replace batteries yourself etc, as I did. Just buy that > and begone will be all reboots due to flaky electric, forever. > Not forever, only as long aa the batteries last. And 95% of the ups's seriously overcharge their batteries just to burn them up in 2 or 3 years. All to get an extra 10% runtime they can advertise. Ask ma bell how long those racks of big, glass tanked lead acid batteries in the back room that power your local phone company, last. Some of them are now more than 70 years old and still as good as new. The secret is the correct charge as measured by the SG of the acid in them. You cannot of course meaure a gell cell that way, the only thing you can do is quit charging them when you stop the charge and measure the tempurature sensitive volts, or in the case of a maintenance charger, reduce it over time until arriving at a voltage that results in a charge current below that which produces gas.
An experiment I did back in the 70's at a tv station with a 335 commings engine spinning a 150 kw alternator, which could run the transmitter at about 40% power since it was a twin klystron transmitter needing nearly 300 kwh for full power. When I walked in the door in '69 the starter batteries were about 2 years old and about burned up since the maintenance charger was a 20 amp gas station type with a 50 ohm current limiter, no smarts at all. 3 months later they didn't have what it took when those 2 big 225 ah truck batteries were switched to 24 volts to start that cummings. So I cut a P.O. and went to Norfolk and bought two new batteries. And put a 2200 ohm current limiter in circuit to replace the 50 which was litterally boiling the batteries. 2 weeks later they were still warm and gassing so I changed the resistor to 4.7k ohms. Another week and I'd put a 10k in. SG 2 weeks later was nearly 1.28, still too high, 3 or 4 months later the resistor had been raised to 47k, the charging current was then less than 5 milliamps, the SG was still a bit high at 1.27, but the gassing was close to stopped. 8 years later, when I headed on down the road to an office door that said Chief Engineer with my name on it, those two 8 yo batteries were still turning that cum-along 335 everything but wrong side out starting it for its weekly exercise 15 minute run. The start relays closed, the bendix slammed into the flywheel, the first cylinder to hit tdc fired and about a second later the governor hit 1800 rpm and throttled it. All in about 1 short second, and the batteries were then 8 years old. That was in 1977, 45 years ago, maybe they are still there, I haven't checked. While I was there, the alternator on my wagon failed and I got a 120 amp version off a wrecked ambulance and built my own voltage regulator, putting in 4 or 5 times the tempcomp that factory regulators give. Kept a 600 cranking amp battery at around 1.265 SG. No gassing, no water loss, started a 348 pumpjack in -30F weather like it was summertime. The wild tempcomp put that alternator wide open for around a minute after starting but the headlights were a little bright. W/O adding any water, that alternator, regulator and battery were moved to the next 3 wagons I bought while living there. So I think I know a bit about Lead acid batteries. But the little cyberpower 650 I put on the rpi4 doesn't see a very much measurable load, so if the standby doesn't start, it dumps the power to the pi 2 minutes after I pull the plug, bummer & hard on the pi. Idiotic even. from upsc myups: ups.delay.shutdown: 120 ups.delay.start: 0 ups.load: 8 8 watts to run the pi and its interfacing, and the 120 seconds to shutdown is not adjustable. IMO I got took. OTOH it was only 40 bucks. shrug. The 20kw standby is up and running in about 4 seconds, so the 120 does cover it. --< there is no space here Piotr, so your sig gets copied in the quote, put a space after the -- and your sig will, or should, disappear in replies from others to your posts. > With kindest regards, Piotr. > > ⢀⣴⠾⠻⢶⣦⠀ > ⣾⠁⢠⠒⠀⣿⡁ Debian - The universal operating system > ⢿⡄⠘⠷⠚⠋⠀ https://www.debian.org > ⠈⠳⣄⠀⠀⠀⠀ Thank you Piotr. Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>
