Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.chem.electrochem.battery,alt.energy.homepower,sci.electronics.repair,alt.energy.renewable
|
|||
|
|||
Building a "Robinson Crusoe" Battery
Too_Many_Tools wrote:
Reading the thread on the Voltaic pile in sci.chem.electrochem.battery, I started considering what would one have to do to build a "Robinson Crusoe" battery to power equipment in an emergency. Assuming a battery of 12v and respectable current to power communications equipment, how would you do it? What materials would you use? How would you charge it? I look forward to your contributions. TMT I've been wondering along similar lines.. I've been wondering how I could make a reasonable ~12V battery,cheaply and easily. Maybe some sal****er cells,built up in Tupperware containers? Assuming maybe 0.5V per cell,and (if they're large enough) perhaps 10AH? 24 containers in series,it would be fairly large! If we can find some good electrode materials,the cell voltage may go up,so we would need less cells/containers Salt and water are both readily available,and pretty cheap,so the electrolyte could be replenished easily enough...(any ideas for something better,that's easy to get,and fairly cheap?) But,I'm not sure what would be best to use as "plates",keeping the cheap,and easy concept in mind.(They will eventually corrode away,right?) Perhaps some kind of setup with pipes-inside-of-pipes. Pehaps you could then build the cells up inside of some lengths of PVC? 4 inch diameter PVC,maybe 3-4 feet long,with a copper pipe inside of a steel pipe,inside of the PVC pipe? Keep a bag of salt next to it,and when the power goes out,dump some salt and water in the cells,and turn on a (LED) light or something for a while.. could be handy. I recall seeing an "emergency battery" that used sea/salt water for an electrolyte..apparently it went through electrodes quickly.. But it had a decent capacity,and was fairly small,maybe half the size of a car battery? But I've no idea what exactly they used for electrodes. It could be useful to have a "backup" battery with an infinite shelf life,untill you fill it. Perhaps then you could just rinse it out,and store the electrolyte (or not,sal****er is fairly non-toxic,shouldn't be an issue to dispose of/dump.) and store it untill you need it again? I'd actually like to build something like this,but at this point it's just a half-thought bouncing around my brain. If you have any ideas,I'd like to hear them! |
#2
Posted to sci.chem.electrochem.battery,alt.energy.homepower,sci.electronics.repair,alt.energy.renewable
|
|||
|
|||
Building a "Robinson Crusoe" Battery
phatty mo wrote:
Too_Many_Tools wrote: Reading the thread on the Voltaic pile in sci.chem.electrochem.battery, I started considering what would one have to do to build a "Robinson Crusoe" battery to power equipment in an emergency. Assuming a battery of 12v and respectable current to power communications equipment, how would you do it? What materials would you use? How would you charge it? I look forward to your contributions. TMT I've been wondering along similar lines.. I've been wondering how I could make a reasonable ~12V battery,cheaply and easily. Maybe some sal****er cells,built up in Tupperware containers? Assuming maybe 0.5V per cell,and (if they're large enough) perhaps 10AH? 24 containers in series,it would be fairly large! If we can find some good electrode materials,the cell voltage may go up,so we would need less cells/containers Salt and water are both readily available,and pretty cheap,so the electrolyte could be replenished easily enough...(any ideas for something better,that's easy to get,and fairly cheap?) But,I'm not sure what would be best to use as "plates",keeping the cheap,and easy concept in mind.(They will eventually corrode away,right?) Perhaps some kind of setup with pipes-inside-of-pipes. Pehaps you could then build the cells up inside of some lengths of PVC? 4 inch diameter PVC,maybe 3-4 feet long,with a copper pipe inside of a steel pipe,inside of the PVC pipe? Keep a bag of salt next to it,and when the power goes out,dump some salt and water in the cells,and turn on a (LED) light or something for a while.. could be handy. I recall seeing an "emergency battery" that used sea/salt water for an electrolyte..apparently it went through electrodes quickly.. But it had a decent capacity,and was fairly small,maybe half the size of a car battery? But I've no idea what exactly they used for electrodes. It could be useful to have a "backup" battery with an infinite shelf life,untill you fill it. Perhaps then you could just rinse it out,and store the electrolyte (or not,sal****er is fairly non-toxic,shouldn't be an issue to dispose of/dump.) and store it untill you need it again? I'd actually like to build something like this,but at this point it's just a half-thought bouncing around my brain. If you have any ideas,I'd like to hear them! What about the water activated lights in lifejackets? Quite small, aceptable current, but once wetted they can't be shut down; the cell continues to degrade if disconnected. |
#3
Posted to sci.chem.electrochem.battery,alt.energy.homepower,sci.electronics.repair,alt.energy.renewable
|
|||
|
|||
Building a "Robinson Crusoe" Battery
phatty mo wrote:
I've been wondering along similar lines.. I've been wondering how I could make a reasonable ~12V battery,cheaply and easily. I've done just what you talk about, so can offer a few details on mine. Maybe some sal****er cells,built up in Tupperware containers? Here you can buy flat multicompartment cases for £2, with 18 sections, used for storing screws etc. These are ideal as long as you can keep the thing horizontal while active. Tip it up and the water would run between cells. Assuming maybe 0.5V per cell,and (if they're large enough) perhaps 10AH? I think people are underestimateing here. I used an M3 bolt and a bit of carbon, which will fit into a roughly 1" bottle cap, and got 1v 0.5A all day. Thats 5Ah or more. So a multicompartment tray would provide several times the Ah at 18v. 24 containers in series,it would be fairly large! If we can find some good electrode materials,the cell voltage may go up,so we would need less cells/containers Well... the more V you want out, the faster it corrodes. Mine gave very little out after 24hrs, but scraping the steel renewed it, so I'd go for long service life as far as poss. I reckon one could easily improve on steel as an electrode, but its free in large amounts. Salt and water are both readily available,and pretty cheap,so the electrolyte could be replenished easily enough...(any ideas for something better,that's easy to get,and fairly cheap?) exactly But,I'm not sure what would be best to use as "plates",keeping the cheap,and easy concept in mind.(They will eventually corrode away,right?) yes, thats the nature of batteries. The lower the whatnot of the plate materials, the slower they corrode. So pick one plate as low as poss on your electrowhatever it is scale, and the other will determine voltage and life. Perhaps some kind of setup with pipes-inside-of-pipes. Pehaps you could then build the cells up inside of some lengths of PVC? lot of work though, when you can just use scraps like food tins etc 4 inch diameter PVC,maybe 3-4 feet long,with a copper pipe inside of a steel pipe,inside of the PVC pipe? holy ---, what are you going to power off this thing? Keep a bag of salt next to it,and when the power goes out,dump some salt and water in the cells,and turn on a (LED) light or something for a while.. could be handy. whats needed is to scrape the electrode, not add salt. A steel bristled brush works, but of course will corrode away rapidly itself. I recall seeing an "emergency battery" that used sea/salt water for an electrolyte..apparently it went through electrodes quickly.. But it had a decent capacity,and was fairly small,maybe half the size of a car battery? But I've no idea what exactly they used for electrodes. It could be useful to have a "backup" battery with an infinite shelf life,untill you fill it. exactly. Perhaps then you could just rinse it out,and store the electrolyte (or not,sal****er is fairly non-toxic,shouldn't be an issue to dispose of/dump.) and store it untill you need it again? right, but bear in mind its not just salt water once its used. You'll have FeCl in there as well, if you use steel. I'd actually like to build something like this,but at this point it's just a half-thought bouncing around my brain. If you have any ideas,I'd like to hear them! These things work very well, but their one problem is very short service life. And that renders them not the most useful IRL. NT |
#4
Posted to sci.chem.electrochem.battery,alt.energy.homepower,sci.electronics.repair,alt.energy.renewable
|
|||
|
|||
Building a "Robinson Crusoe" Battery
|
#5
Posted to sci.chem.electrochem.battery,alt.energy.homepower,sci.electronics.repair,alt.energy.renewable
|
|||
|
|||
Building a "Robinson Crusoe" Battery
phatty mo wrote:
wrote: phatty mo wrote: Wow,I had thought about those little multi-compartment boxes,but I didn't think a "simple cell" that size would have any real juice to it.. I have a couple here i could play with. Think what a dry cell that size can do. 500ma? really? Nice! Yes I was surprised how powerful it was. What did you use for electrodes and an electrolyte,just sal****er? salt water electrolyte, carbon and steel electrodes. The carbon doesnt corrode, but the steel does, and rapidly. 4 inch diameter PVC,maybe 3-4 feet long,with a copper pipe inside of a steel pipe,inside of the PVC pipe? holy ---, what are you going to power off this thing? In short,as much as I can! Never mind AA and D cells, I can imagine people walking into shops, and asking for Triple Z cells please. What would it really produce? Mine was 1" wide, 0.5" deep, and I made no attempt to get max electrode area into there. Yours is 4" wide, 48" long... so you've got 4^2 x 48/0.5 times the voolume there. Thats 1526x as big. So you should get around 700A at 1v. 0.7kW per cell, so yes you really could heat the place on a set of those. Now design them properly so you get optimised electrode areas to electrolyte capacity, and youre likely looking at 2 or 3 thousand amps. Dont even think about shorting one of those! If the power goes out,and my main battery bank is drained,or i'm not near it (away from home)it would be nice to have a 12V battery I could run some lights,and a radio or something off of.A large capacity would be a good thing. Ha, reckon youre a few orders of magnitude OTT there 10AH is just a starting point,if I could I'd like to build a (say) 50-100AH version. (the equiv of a car battery or two.) Well yours would be what, say 1000A for 10 hrs... 10,000 Ah Maybe run some CFL lights from an inverter in the house or something for a day or two? Perhaps the TV for a bit? My PC? CB radio,scanner,cellphone charger,etc..? Yours would more like light the town, power the local cinema, power the university computing department, and the local radio transmitter. whats needed is to scrape the electrode, not add salt. A steel bristled brush works, but of course will corrode away rapidly itself. Well,i was thinking of storing the battery "Dry" untill needed (and possibly draining/rinsing it after use) that way the electrodes won't dissolve away in the meantime.. yes, thats necessary. So to use it,you'd pour sal****er (or other electrolyte) in there,and connect a load. Agitation is a good point though. I wonder if a small air pump would help..maybe put a "bubble stone" for aquariums in the bottom of each cell to help keep the electrolyte mixed,and help knock the 'crust' off the plates? Well, I don know what you'll use, but with steel the crust was attached pretty hard. An angle grinder would make more progress than an airstone if youre using steel. right, but bear in mind its not just salt water once its used. You'll have FeCl in there as well, if you use steel. Ahh,yes..good point. Actually,I wonder..if FeCl could be useful for etching printed circuit boards. ;-) (I believe thats what is used as an etchant?) yes, but it wont be anywhere near strong enough. Least mine wasnt after 1 day anyway. NT |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Small electrical motor question. 12 volts 230 Watts on Peg-Perego power wheel jeep | Electronics Repair | |||
Cordless phone handset battery, usage? | Electronics Repair | |||
help! laptop's CMOS battery is dying | Electronics Repair | |||
Battery Problem QX4 Solved | Home Repair | |||
Building Warrants - Buying Flat Without | UK diy |