Gravity Batteries - Cheap, Easy, Robust And Awesome For Off Grid

[Music] hi so I appreciate the title may have been a little misleading I mean it isn't but it may have made you think you were coming to see something you're not so if you're coming to see a mysterious device that harnesses the power of gravity to generate electricity I'm sorry to disappoint you what this is about is about gravity batteries and gravity batteries are awesome in themselves and really worth knowing about but there are religious batteries that keep the reactants separate by the force of gravity now if what you were expecting was a gravity machine you're probably best just to skipping and and moving on really if you're interested in manufacturing cheap batteries that you can use yourself at home that are very low skills to make and do a really quite good job then you probably be a good idea if you watch the video you may well enjoy it anyway I thought I'd put that right at the beginning because I understand that people may have clicked on the video expecting one thing and getting something else and be quite upset about it okay that said now I'm absolutely fascinated by our turn-of-the-century technology and I have a whole bunch of this stuff called the model engineer an amateur electrician that started publication I think is 1898 1899 something like that 1976 they did a whole lot of Fastenal reproductions of the early editions and I bought a bunch of them when I was 25 and I've had them ever since and they're absolutely stuffed with really interesting articles on steam engines gramophones and whim Hurst machines wiring up your own dynamos all kinds of stuff including batteries we have a bit of a modern obsession with batteries or we think we do we think that we're obsessed with getting better and better batteries don't actually whom year is this stuff you find that this has been an obsession since the 1800s right the way through it's absolutely amazing now a lot of stuff that you find done when research is done really it's a question of looking what went before and then almost updating it with modern methods and materials and that can be a really valuable and interesting way of proceeding when looking for something new have a look at what went before and then update it with modern materials and it can be just very very fruitful so I'm gonna do a series of videos really on the batteries that are contained in this stuff because him we look at those and develop them with modern materials there is a high probability of generating something brand new now back then there was a whole group of batteries called gravity batteries and they were extremely popular because people didn't have the same kind of stuff that we've got that didn't have wall outlets so if they wanted to make an electrical machine and wanted to make a lettuce it battery which they called an accumulator and charge that accumulator they needed a source of primary energy and for that they were using these gravity batteries an awful lot of the time and so they were extremely popular the obviously fell out of favor obviously they're nobody really knows about them anymore which is just amazes me but nobody knows about them and they're extremely simple to make and very robust so there's a whole host of them I'll be covering some of the more interesting ones that I think we can replicate and improve upon being the whole point of it and I've chosen this one to start with it's from volume 4 which is published in 1901 and it's a gravity battery based on zinc and copper now the writer of the article says that he run his batteries for months at the time without having to attend to them he just make up a bank of them and leave them for two three months and then every two or three months go back and have a look at them and maybe refresh them when you're thinking about that care then let acid my battery bank teach these days actually that's a surprisingly efficient lack of maintenance little setup now we're going to make a small one the guy in here makes absolutely huge ones he makes them things that size and he puts like half a kilo of material in there and he runs us for ages and ages and ages we're just gonna make a little one like this as a demonstration and it's really simple you need a bit of copper and it's copper foil because what's going to happen is that the device is going to sediment copper and this folio will get thicker so you don't need an awful lot of it you just need a little bit of copper foil cut it in an L shape and this one you bend round like an S shape and stuff it into the bottom of your jar like that so we can see we've got a little bit protruding out there that we're going to connect to get a rest yet and we're going to connect to that bit protruding there the next thing you do is put a ton of copper sulphate in there perhaps not that much there we go it's a copper sulphate in with our copper now when you're making this battery the guy recommends it uses zinc sulfate solution doesn't specify how much they sulfate but anything really just enough to get the action going he also says you could use a drop of sulfuric acid if you want I've gone for sink sulfate obviously because I forgot to bring gloves don't want to be getting sulfuric acid on my hands sinks off it's really nice and easy to get hold of and really nice and safe and now as the battery runs right what it does is replaces the copper with the sink and that the zinc sulfate solution is gonna get more and more concentrated so we'll go through in a minute how to maintain these batteries but right now but a bit as a sulfate and a bit of water and I've only put 2 teaspoons and it really doesn't matter how much you put in we need enough water to bring that up to about here so we need to cover the copper sulfate cover the cut the copper strip and leave a bit extra for putting our other side in there now other side is going to be a zinc it's going to be the zinc plate so obviously the displacement reaction and because you've got these things arranged in layers that gravity keeps those layers separate the copper sulfate gets eaten up forming zinc sulfate and that the zinc sulfate every now and then you're gonna have to siphon off and replace with fresh water so you stick a siphon in siphon off the zinc sulfate solution which is just gonna get more and more concentrated and add a bit of water to it and you can literally drop the copper sulfate in there so we just fill that up there we go you can see already it is actually not really mixing that well now I've got some sheets of zinc here and what I'm going to do is just fold that sink over to form myself a block of zinc the zinc block needs to go a little bit away from the copper so that later on when you want to drop copper sulfate in there you can do that easily now obviously and a small one like this is a bit challenging on a big one like that no problem at all you could also I guess just grab yourself a sacrificial anode from a marine jugular and use that so you use a boat anode connect the boat and hood up and you'd be away and the zinc just needs to go a little bit lower than the copper now what I've got here is a bit of useful rubber and I often use pew butyl rubber as a kind of blue tack and I'm basically going to blue tack the zinc onto the side here just below the level that I've just put it out that is my battery now then it will salt creep as the zinc sulfate increases and it will evaporate so just stop that I've got a bit of here is ordinary machine oil for that gently on the top there we go that forms a seal which will stop that happening if you want to remove that you stick a siphoning siphon it off you can drop the copper sulfate strength away through the oil takes about 15 minutes or so to really get going so we're going to give it a few moments and then we'll see what we've got okay so I've given that 15 minutes and you should be able to quite clearly see the separation now which is why it's a gravity battery everything's being held in that place just by gravity and you can see the copper sulfate you can see that the solution above which was quite blue when we first have the zinc sulfate actually it's clearing up so over time that will actually go much clearer the oil cap that you can see in the sink is just below the oil and into the solution and as our s shet copper now to show that this works what I've done is I've got a little mode two here on a black background with a white propeller and if I connect that up there we got a little motor is spinning so that is outputting energy right now it is a primary battery so it's going to last as long as the zinc and copper sulfate so if you want to recharge this in inverted commas you can also think of it as a mechanically rechargeable battery but if you replace the copper sulphur until the sink has gone well the zinc is gone you probably want to wash everything out and redo it but that's best on an 1889 design and surely we can come up with a better design than that where we have a mechanically rechargeable sink battery that could be used in automotive applications or a moving applications obviously something like this you have to sit it on the shelf and you can't really shake it or you'll disturb the gravity but like I say the actual action of the battery the fact that it's pumping out energy and will do so for all that time until that's gone as I say the guy put a half a kilo of copper sulphur in here and run it for three months so he said we've got to be able to come up with a better design of that that will enable that and so I thought I'd show you that really so and hopefully spark some ideas about how to redesign that simple gravity battery now in output terms we can see is actually working their ego is 1.33 volts from that particular set up so bad a vault uh and that's very cool okay so what I'm gonna do now is clean anything it now move all this stuff and show you the second gravity battery which isn't rechargeable okay so this one's the rechargeable version no the copper zinc is rechargeable in a mechanical sense you know you can add ingredients to it to keep it going this one is actually rechargeable an electrical sensor connected up to a power supply now it's much simpler but it does use zinc bromide now we've been talking about the signal bromide no the batteries so this one's kind of cool is you basically arrange your suffer a jar and I've got a little thing here you could use a big one and here I've got a carbon electrode now what that is is a bit of metal glued onto this stuff which is HDPE high carbon filled HDPE and to protect the metal and then a bit of carbon painted on top of that to create my carpet electrode which is circular and sits at the bottom now obviously that's going to be the positive because all that bromine negative is going to get attacked attracted to here and bromine in solution is a higher density dancing bromide solution so that gravity will keep it at the bottom there making it perfectly safe which if you think about it is really awesome now the battery power is directly related to the energy the amount of zinc bromide that you can put in there zinc bromide is an absolutely amazing salt and you can get huge concentrations of it it's astonishing actually how much will dissolve now I'm just gonna put a rung on the mountain because we're just demonstrating this but the molarity can go up as far as five seven months it's a standing and I'm only going to make this up to about 60 milliliters there are about 60 milliliters of that and again I've got myself a piece of zinc that I'm going to fold over and over and that will sit just like the last piece of zinc did just under the absolution top and then we'll top that off with a little bit of motor oil shall we pop that in now now I did go through how to make zinc bromide if you can't buy it and there is a video on how to make it from sodium bromide and zinc sulfate both of which just really ridiculously easy to get hold of so there is my basic gravity sell carbon zinc and here is my zinc bromide solution and we for one into the other until it's just covering the zinc now of course nothing is going to happen because it's not charged so this one we need to charge and there we go that is the gravity cell same thing bit of motor oil on top to seal everything in and although people worry about bromine this gravity battery keeps everything in check now bromine batteries are really curious things in that they charge not according to the cell voltages at 1.9 5 volts but according to the surface area of the electrode and in this case it's this bottom electrode it's not very big and it's about 20 to 50 milliamps per square centimeter is the charge current so negative to the zinc positive to the carbon and we should charge it around about 20 to 50 million powers per square centimeter and I'm going to turn that on and give it some voltage and if it sucks up quite a lot of amperes almost immediately now let's take a little while to start so what I'm gonna do is leave that charging until we can see that bromine formed and then back to you okay it's been charging about 10 minutes at quite high voltage actually I'm charging it as seven volts but that's the demonstration you should be able to see the bromine collecting in the bottom there's that golden brownish color and then there's a layer of the oil on top okay so that's had about 10 minutes to charged unless you wouldn't get anything out of it we'll use our little motor demonstration like I say the voltage is about 1.8 volts and there we go here we go in that awesome so there's our motor spinning away there from our zinc bromide to gravity battery this battery actually is really kind of awesome the layer of oil does capture any bromine that might come off but it also captures any hydrogen now this does off gas a little bit particularly if you charge it the high voltage that I just charged you that if you charge it the right voltage then actually it doesn't off gas that much at all and you get this nice banded separation between the bromine and the zinc bromide solution but the hydrogen gets captured long enough for the zinc oxide that's formed in here to form zinc hydroxide so it actually catches the hydrogen as well which is very cool as it charges obviously what it's doing is reducing the concentration of the zinc bromine using bromide in there and so the resistivity goes up so it's quite a good idea to took another salt in there is an assistant salt and sodium bromide works really well so five moles of zinc bromide one mole of sodium bromide would work really really well keeping enough iron concentration the solution that the series resistance of the battery doesn't go too high and like I said yeah I give it about a 10-minute charge and it's still whizzing away there so there we got to gravity batteries one this mechanically rechargeable or if you like a primary and one that is actually rechargeable now I apologize if gravity battery may do you think of something else but I thought those were absolutely awesome ideas from the eighteen hundreds that really if we look at again we must be able to improve so I thought I would share that with you I hope it was of interest and thank you very much for watching

Channel: Robert Murray-Smith

Views: 309,776

Rating: 4.8812094 out of 5

Keywords: batteries, off grid, home storage, diy, diy battery, fwg, robert, battery, murray-smith, home, storage, built, alternative, energy, power, electricity, science, fair, project, made, stem, steam

Id: p8lyJhk4MjQ

Length: 19min 21sec (1161 seconds)

Published: Tue Apr 07 2020