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WeWork with the good OSHA ideas
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Feb 19, 2020 20:19
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this man is my new hero
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Feb 19, 2020 20:42
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Narrator: It was urine in the cup
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Feb 19, 2020 20:52
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Pigsfeet on Rye posted:Narrator: It was urine in the cup Pee is stored on the walls
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Feb 19, 2020 20:54
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Kafouille posted:That's not reacting with air, the knife is shorting it out internally and it's entering thermal runaway, damaging more cells and dumping it's whole charge in a few seconds, making a shitton of heat and oxygen. Most things are combustible with enough heat and oxygen, so it bursts into fire. do fully charged batteries explode better than dead ones?
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Feb 19, 2020 21:11
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i spent about 3 minutes trying to remember the technical terms for any of that before just shrugging abnd packing another bowl. i want you all to know i tried.
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Feb 19, 2020 21:12
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Platystemon posted:Have your coworkers flirted with the danger of diesel exhaust fluid? I really like the “[activity] yielded ## emergency landings” language. I’m picturing middle management at the OSHA factory proudly submitting their report about how productivity increased 4% this quarter.
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Feb 19, 2020 21:33
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PHIZ KALIFA posted:do fully charged batteries explode better than dead ones? they absolutely do, and one of the steps for disposing of hobby-grade lipo batteries is to leave them plugged in to a simple circuit like a 12v car battery for a few days so they get completely discharged. You can also do this by submerging the battery packs in salt water which does the same thing but submerged in water for extra fire safety They even make purpose built little circuits for this now, you leave your pack plugged in to them and it fully discharges the battery to 0v which basically kills the chemistry and destroys the battery, or press a button and it only discharges until it hits 3.7v which is the "storage voltage" the level you put the batteries to when you wont be using them for a while. Leaving batteries fully charged or discharged for long periods also messes with their chemistry. they're super finnicky but the best power density we have right now bring back old gbs fucked around with this message at 21:38 on Feb 19, 2020 |
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Feb 19, 2020 21:34
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i haven't looked at battery science in 20ish years, what's the best way to care for laptop and phone batteries? my laptop's battery is now totally internal and can't be swapped out when full, and i let my phone run till shutdown probably 2-3 times a month. i figure the power management firmware is probably smarter than me about this by now, but what's the actual best practices?
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Feb 19, 2020 21:40
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PHIZ KALIFA posted:i figure the power management firmware is probably smarter than me about this by now, but what's the actual best practices? This is pretty much correct and what you're doing right now is safe. Allow the battery to get very low once or twice a month to keep it healthy and fully discharge it if you know the device is not going to be used for several months.
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Feb 19, 2020 21:50
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The lithium batteries in your laptop and phone don't require any special treatment from the user standpoint. They have built-in charge controllers that will ensure they don't get over- or under-charged. Characterizing the lifespan of a rechargeable battery is a bit complicated but it goes like this: The battery will be specified to have a lifetime of N charges before its capacity degrades to M percent of its original value. For instance, 1000 cycles to 50 percent. This means that after 1000 full charge and discharge cycles, the battery will only last half as long as when it was new. A cycle the process of charging from 0 to 100%. Charging from 50% to 100% counts as half a cycle, so you can do that 2000 times. 90% to 100% is one-tenth of a cycle. Etc. That's close enough for most purposes. The actual behavior is a little more complex than that because the degradation is not linear. Most of the microscopic damage to the cell happens when it's close to full or close to empty. If you never charge your battery to more than 70% and never discharge it below 20%, it will actually last longer than 1000 full cycles (which would normally be 2000 of those half-cycles, recall). Many products take advantage of this; hybrid cars usually do not use their full battery capacity, perhaps only charging from 10% to 90% of nominal charge, in order to increase the pack's lifespan. If you feel like it, you can janitor your phone battery to keep it hovering around a half-charge for increased lifespan -- but then you're never going to use the full capacity anyway so it cancels out and is pointless. Basically just don't worry about it. haveblue posted:Allow the battery to get very low once or twice a month to keep it healthy and fully discharge it if you know the device is not going to be used for several months. Wrong. Lithium batteries are happiest at somewhere between 50% and 90% of full charge. Fully discharging the battery and then leaving it for several months is a good way to cause damage because the natural self-discharge may bring the cell below its normal cutoff point. If you plan to leave the device unattended for several months, charge it up first.
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Feb 19, 2020 21:56
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Sagebrush posted:
exactly, this was what i was wondering, when the phone display says "100" is it actually 100 or is it 80% of the max capacity, to ensure a longer lifespan even at the cost of more frequent chargeups.
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Feb 19, 2020 22:01
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PHIZ KALIFA posted:exactly, this was what i was wondering, when the phone display says "100" is it actually 100 or is it 80% of the max capacity, to ensure a longer lifespan even at the cost of more frequent chargeups. That's going to be defined by the phone's firmware and/or the charge controller. Depends on the battery chemistry, but a lithium cell might have a maximum voltage before damage of 4.20v and a minimum value of 2.90v. Those voltages get set as 100% and 0% by whoever is making the decision. You could squeeze out a little more capacity by setting 0% as 2.85v, but going too low will cause the battery to degrade faster, and very low will cause damage. To maintain a longer life you set your endpoints as say 3.0v and 4.1v. *once again it is even more complex than this, because once the battery's voltage endpoints have been defined the phone will characterize how many milliamp-hours the battery can produce by measuring the current over time (coulomb counting, it's called) and then use that figure to report its charge state. but the voltage thing is close enough
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Feb 19, 2020 22:07
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i'm not sure either way, i just know i don't dare leave the thing plugged in overnight because that turbopower charge plug dealy gets warm.
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Feb 19, 2020 22:08
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Sagebrush posted:Wrong. Lithium batteries are happiest at somewhere between 50% and 90% of full charge. Fully discharging the battery and then leaving it for several months is a good way to cause damage because the natural self-discharge may bring the cell below its normal cutoff point. If you plan to leave the device unattended for several months, charge it up first. After talking to multiple cell manufacturers, we settled on ~50% for storage I think. Storing it slightly lower than that might reduce degradation, but it also decreases the amount of time you can safely leave it in storage. When you then need to account for quiescent current from whatever the battery is connected to, along with increased self-discharge due to being potentially stored in hot warehouse or a very hot car (for instance), you can increase that to 60-80%.
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Feb 19, 2020 22:13
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Sagebrush posted:That's going to be defined by the phone's firmware and/or the charge controller. Depends on the battery chemistry, but a lithium cell might have a maximum voltage before damage of 4.20v and a minimum value of 2.90v. Those voltages get set as 100% and 0% by whoever is making the decision. You could squeeze out a little more capacity by setting 0% as 2.85v, but going too low will cause the battery to degrade faster, and very low will cause damage. To maintain a longer life you set your endpoints as say 3.0v and 4.1v. You also need to decrease the charge termination voltage when you have series connected cells (such as in a laptop) and mismatches between the cells mean you can end up overcharging some (even if they're "balanced", impedance mismatches still result in voltage differences when charging voltage is applied). This might be less of an issue with higher-grade S-ranked cells (I lol'd when I realized the japanese companies actually grade their cells from S to A to B to C and so on), but I never bought those. Aside from the charging voltage thresholds set by the battery (for smart batteries) or charger, the device itself can also lie to you about it's charge state. Standard Li-Ion cells will probably blow up if you tried to trickle charge them by repeatedly topping off a battery as it slowly discharges (from self discharge or quiescent current from whatever circuitry its connected to). It's common for a battery that is fully charged to remain "fully charged" until it discharges to say 95%, at which point the charger will kick back in. Until this happens, though, some devices can and will lie to you about whether or not the device is charging and/or fully charged.
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Feb 19, 2020 22:25
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PHIZ KALIFA posted:do fully charged batteries explode better than dead ones?
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Feb 19, 2020 22:30
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DandyLion posted:Pee is stored on the walls OSHA: explosive laughter
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Feb 19, 2020 22:31
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evil_bunnY posted:fully charged lipo burn *real* good A fully charged high-capacity smartphone battery contains several tens of kilojoules of energy, comparable to a small cup of gasoline or a few grams of TNT. Letting all that out in a few seconds instead of the designed several hours is Not Good.
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Feb 19, 2020 22:43
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I'm not a brick laying pro, but I'm pretty sure those are lovely-rear end bricks and he's placing them wrong. Load bearing holes? 
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Feb 19, 2020 22:47
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Beef posted:Load bearing holes? You leave my wife out of this!
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Feb 19, 2020 22:49
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It is interesting to consider that really, as battery technology develops they should get more dangerous. That said, I helped with the destructive battery test yesterday I mentioned earlier. We shorted out a lithium cell with no protection circuitry. We were fully expecting smoke flame fireball action, but... nothing. We measured 300 amps of current draw but it only got to 114 degrees C and there was a tiny whisp of smoke out the vent and a few mm of swelling. Not going to lie I was pretty disappointed. So safer cells are being developed, but there will always be risks associated with storing a lot of energy in a small place. Splode fucked around with this message at 23:33 on Feb 19, 2020 |
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Feb 19, 2020 22:51
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haveblue posted:A fully charged high-capacity smartphone battery contains several tens of kilojoules of energy, comparable to a small cup of gasoline or a few grams of TNT. Letting all that out in a few seconds instead of the designed several hours is Not Good. I mean, that's the scary way to say it. It's also about the same energy as a single Jolly Rancher. You're right, though, the power is the dangerous thing - it's a lot like burning the candy in a pure oxygen environment, but in your pocket.
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Feb 19, 2020 23:04
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PHIZ KALIFA posted:i'm not sure either way, i just know i don't dare leave the thing plugged in overnight because that turbopower charge plug dealy gets warm. That's a good practice from what I've read, but it was because heat is bad for the battery; leaving it on the charger at 100%, leaving it in a hot car, running maps while driving with the phone in the sun, etc.
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Feb 20, 2020 00:12
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Unreal_One posted:I mean, that's the scary way to say it. It's also about the same energy as a single Jolly Rancher. it's the same energy as 20 micrograms of 235U and that sounds pretty pitiful to me!
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Feb 20, 2020 00:13
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https://i.imgur.com/h8tGcdL.mp4 Chainsaw protective pants. Imgur comments say this has been around a while, the Kevlar peels off and jams the saw.
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Feb 20, 2020 01:05
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https://www.youtube.com/watch?v=jIJTEm0qNuo
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Feb 20, 2020 01:37
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Cartoon Man posted:https://i.imgur.com/h8tGcdL.mp4 was expecting dickbutt
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Feb 20, 2020 01:49
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Cartoon Man posted:https://i.imgur.com/h8tGcdL.mp4 Yep, chainsaw chaps. I was clearing a deadfall tree from a country road in the early 2000s with a chainsaw, and I had chaps and a face mask on. I had no mobile reception and was more than 20km away from the nearest person. I cut a branch applying steady force and letting the chainsaw do the work, without realising that the branch was full of dry rot. The chainsaw went straight through it like a hot knife through butter and swung down to smack me on the middle of the inner thigh before I could get my wrist up to hit the chain brake. The saw stalled out as it mulched my chaps. It was in femoral artery territory, so considering where I was I'm pretty comfortable saying that pair of assless pants saved my life.
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Feb 20, 2020 02:02
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Maybe there's something wrong with me, but watching that makes me wonder how one applies for that job, and what qualifications it takes 
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Feb 20, 2020 02:10
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Memento posted:Yep, chainsaw chaps. I was clearing a deadfall tree from a country road in the early 2000s with a chainsaw, and I had chaps and a face mask on. I had no mobile reception and was more than 20km away from the nearest person. Goddamn, I got sweaty reading that. Assless chaps, ironically, have saved more asses than rear end-full chaps.
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Feb 20, 2020 02:12
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Dirt Road Junglist posted:Maybe there's something wrong with me, but watching that makes me wonder how one applies for that job, and what qualifications it takes Well, for starters, you have to be mentally broken.
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Feb 20, 2020 02:16
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Cartoon Man posted:https://i.imgur.com/h8tGcdL.mp4 They’re ineffective with electric chainsaws, which cannot stall out.
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Feb 20, 2020 02:25
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thread title relevant https://i.imgur.com/Wa3KtqV.mp4
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Feb 20, 2020 03:41
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LifeSunDeath posted:Goddamn, I got sweaty reading that. Assless chaps, ironically, have saved more asses than rear end-full chaps. OSHA IV: Assless chaps save more asses than pants!
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Feb 20, 2020 04:35
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starkebn posted:thread title relevant Wow, that's some prison engineering type poo poo.
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Feb 20, 2020 04:36
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Can't you do that same thing with a 9V battery much easier (and safer)?
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Feb 20, 2020 08:18
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That requires you to have a 9V vattery
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Feb 20, 2020 08:46
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Dirt Road Junglist posted:Maybe there's something wrong with me, but watching that makes me wonder how one applies for that job, and what qualifications it takes I did some similar stuff on draglines and all it took was a 'Working at Heights' permit, plus the qualifications for my actual task. They wanted to put me in a dogbox and crane me to the tip of DL-booms but I always walked up to sych myself up for being on teh top while it swings over a pit.
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Feb 20, 2020 11:55
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| # ? May 31, 2024 15:44 |
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Zernach posted:Can't you do that same thing with a 9V battery much easier (and safer)? I set a scrap of paper on fire with the toaster when the pilot light on my stove had gone out and I didn't have any matches or lighters around.
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Feb 20, 2020 12:19
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