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Grant (SSSF) Send message Joined: 19 Aug 99 Posts: 13720 Credit: 208,696,464 RAC: 304 |
One of the APCs has the factory batteries, the other has four Group 24 size AGM batteries (not exactly factory approved). I opted to replace my UPSs 2*7AH batteries with a couple of marine batteries (110AH ea). Went from 15min backup at 75% load to over 8 hours. Fully recharging after battery low cutoff takes about 3 days; most outages (2-4hours) it takes less than 24hours to fully recharge. EDIT- BTW, is it just me or is Ned's Avatar getting younger? Grant Darwin NT |
littlegreenmanfrommars Send message Joined: 28 Jan 06 Posts: 1410 Credit: 934,158 RAC: 0 |
Anyone remember the formula for converting between peak voltage and RMS? It's starting to come back... isn't the reverse 1.4.4? or am I thinking of three phase now? lgm <<<<<<gettin' old |
iceMan Send message Joined: 26 Dec 00 Posts: 4 Credit: 460,792 RAC: 0 |
Anyone remember the formula for converting between peak voltage and RMS? .707 rings a bell with me too. 1.414 would be recriprocal of that. 1.73 is the multiplier for three phase. Hey Matt, I always enjoy the pictures. Worth a thousand words each, y'know. Later, John |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
One of the APCs has the factory batteries, the other has four Group 24 size AGM batteries (not exactly factory approved). You want to be careful with batteries, for a couple of different reasons. Standard wet-cell marine batteries give off hydrogen while charging, and anyone who has seen the Hindenburg disaster film knows what hydrogen can do. It's also corrosive. If you're putting the batteries in an occupied space, they should be sealed, spillproof and something that won't outgas. AGM usually. |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
EDIT- BTW, is it just me or is Ned's Avatar getting younger? She's a pretty cat now, but she was such a beautiful kitten -- about 8 weeks in this photo. |
Robert Ribbeck Send message Joined: 7 Jun 02 Posts: 644 Credit: 5,283,174 RAC: 0 |
One of the APCs has the factory batteries, the other has four Group 24 size AGM batteries (not exactly factory approved). The cause of the hindenburg disaster was more the coating painted on the baloon than the hydrogen. |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
I didn't say hydrogen was the cause, I said hydrogen burns good. It's corrosive. Standard batteries should only be used in a well ventilated area. AGM (and other VRLA) batteries reabsorb the hydrogen internally and do not present the same hazards. |
littlegreenmanfrommars Send message Joined: 28 Jan 06 Posts: 1410 Credit: 934,158 RAC: 0 |
Anyone remember the formula for converting between peak voltage and RMS? Hi Ice... I'm sure I typed 1.414 as it's also the square root of 2. Where the hell 1.4.4 came from, I have no idea. Making more than my fair share of typos this week. I think I need some sleep lol. But thanks for the info :) I haven't touched three phase in nearly 30 years. I got fed up getting dirty, so I joined the Army, and got REALLY filthy! *chuckle* |
iceMan Send message Joined: 26 Dec 00 Posts: 4 Credit: 460,792 RAC: 0 |
Anyone remember the formula for converting between peak voltage and RMS? I'd forgotten that. I did remember 1.73 is the square root of three though. :) |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
Agreed that "hydrogen burns good" (although I would'a said "well", or "very well") but I take issue with the "It's corrosive"! Elemental hydrogen is not corrosive, just explosive... the corrosion from lead-acid batteries is from sulfuric acid, serving as the electrolyte in the storage/release of electrical energy. Anyone remember the old days when you actually hadda top-up your car battery; before the invention of the gel-cell? Sulfuric acid was the culprit there, too - and is the reason why the "well-ventelated area" is still recomended. Basically, putting a charge across water with sulfuric acid in it tears the water apart into hydrogen and oxygen. . Hello, from Albany, CA!... |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
Are you saying that you'd like to have a couple of big marine batteries sitting in your bedroom or den? That's the point I'm trying to make. There are batteries that do not outgas and are safe in an enclosed area, and there are batteries (like the ones in your car) that are fine in well-ventilated areas. |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
I actually have a car-sized (and probably ex-car - I found it on the street - it is a type 75) battery running external (to the computer) fans in my computer room / ex-bedroom. All three (two UPS sized gel-cells and the type 75) batteries have given me no problems with leaking or out-gassing. (so far, at least!) The two UPS battries are for when the type 75 needs charging, BTW. Type 24 marine gel-cel batteries shouldn't be a problem - but the type 27's would be too heavy to manhandle! (I've considered it - I was also a ham radio operator...) . Hello, from Albany, CA!... |
jim little Send message Joined: 3 Apr 99 Posts: 112 Credit: 915,934 RAC: 0 |
<<<<<<<< On the Joys of hydrogen. The flame in air is as near invisible as one can imagine. Same when burned in pure oxygen as in a torch. It is hard to adjust the flame to be proper ratio when used for welding. I used to use a lab torch that I modified for feeding micro torches. Used it for making really small thrmocouples for temperature measurement in very small samples. Another problem with hydrogen in cylinders is that they are very heavy. And hydrogen can embrittle many iron alloys (steel) but not all. So far I have not succumed to adding to any external batteries of our six UPS's at home. On the other hand we have two inverters for our cars that put out 120 watts of 120 volt 60 Hertz. Max possible in car lighter socket is 240 watts. (Twenty amps.) duke |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
You can get an inverter that is rated a heck of a lot higher than 240 Watts - I've seen 'em as high as 2500 watts, possibly even 3k (continuous! - 5k peak) I imagine that anything over about 300 Watts needs to be directly wired (with really low gauge wire, or multiple 12 guage strands!) to the battery or alternator, though… (don't know where to find such a large inverter? - try a truck stop!) Those high-wattage inverters are physically large, and heavy, BTW… Back to hydrogen for a second - the second stage of the Saturn V rockets, that went to the moon, burned liquid hydrogen and LOX... as I recall, the second stages was tracked by the exhaust (hydrogen + oxygen = water) which would condense in the upper atmosphere. . Hello, from Albany, CA!... |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
Yeah, but he said "car lighter socket" which has a 20a fuse. The bigger inverters have to connect to the battery some other way. |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
The 300 Watts is probably a "peak" value, and the inverter really is a 200-240 "continuous" rated item. I know i've seen 300 watters (as specified) with cigarette lighter (they're trying to change the nomenclature to "car accessory outlet", BTW) plugs. . Hello, from Albany, CA!... |
Grant (SSSF) Send message Joined: 19 Aug 99 Posts: 13720 Credit: 208,696,464 RAC: 304 |
You can get an inverter that is rated a heck of a lot higher than 240 Watts - I've seen 'em as high as 2500 watts, possibly even 3k (continuous! - 5k peak) I imagine that anything over about 300 Watts needs to be directly wired (with really low gauge wire, or multiple 12 guage strands!) to the battery or alternator, though… (don't know where to find such a large inverter? - try a truck stop!) The larger capacity inverters generally require 24V or even 48V to run. Grant Darwin NT |
1mp0£173 Send message Joined: 3 Apr 99 Posts: 8423 Credit: 356,897 RAC: 0 |
... and the odds are good that the typical cigarette lighter plug has a slow-blow fuse, so you can draw 300w for a few tenths of a second. |
KWSN THE Holy Hand Grenade! Send message Joined: 20 Dec 05 Posts: 3187 Credit: 57,163,290 RAC: 0 |
You can get an inverter that is rated a heck of a lot higher than 240 Watts - I've seen 'em as high as 2500 watts, possibly even 3k (continuous! - 5k peak) I imagine that anything over about 300 Watts needs to be directly wired (with really low gauge wire, or multiple 12 guage strands!) to the battery or alternator, though… (don't know where to find such a large inverter? - try a truck stop!) Nope, all those I've seen were 12v - I've seen them at truck stops, and the current generation of big rigs run 12v, and several prior generations do, too. (Truck driver talkin' here!) Big-rig trucks generally have 3 12v (type 36 - huge [80+ lbs.]) batteries, but they are run in parallel, so only 12v, but lots of storage capacity - and lots of juice ("Cold Cranking Amps") to turn the monster Diesel engines over, too! The only inverter I've seen installed was 12v 1500 watts, and ran dual 4 guage wire (cable really - about .5 inch [12.5mm] in diameter!) to the battery(ies). (Which, on a big rig, are in the area between the cab and the trailer, below the frame.) . Hello, from Albany, CA!... |
Grant (SSSF) Send message Joined: 19 Aug 99 Posts: 13720 Credit: 208,696,464 RAC: 304 |
Nope, all those I've seen were 12v - I've seen them at truck stops, and the current generation of big rigs run 12v, and several prior generations do, too. (Truck driver talkin' here!) Here in Australia trucks are (or used to be) 24V electrical systems. EDIT- BTW, to avoid confusion here in Australia this is not a truck. These are. Grant Darwin NT |
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