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Gary_Gough

Make it yourself [DIYs & Modifications]

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Want to charge a Li-Ion cell with a 6 volt solar panel?

Here is how to do it properly. Cost of the chip $0.50 in singles.  http://www.digikey.com/product-detail/en/AAT3693IDH-AA-T1/863-1512-1-ND/4246137

Or if you aren't set up for that style of surface mount PCB work. http://www.digikey.com/product-detail/en/MCP73811T-420I%2FOT/MCP73811T-420I%2FOTCT-ND/1649474

The second can be done with a very fine soldering iron tip ( I like a single solid piece of Cat5 stripped and wrapped around the regular iron tip with 3 mm extending out as the working tip ) and needs almost no external parts, but does lack thermal sensing.

The data sheets will teach lots about working with Li-Ion cells :)

Really low tech approach. just to limit voltage, but this actually costs more...

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Edited by Gary_Gough
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How to void your warranty, a photo spread.  ( or, I'm too cheap to throw away good Li-Ion batteries)

What I start with is a quite new 11.4 volt battery pack from an ASUS laptop ( great machine BTW ) that a friend left on till totally discharged and then left it for a few months in that state. Pealing the label gives the first glimpse inside. After grabbing either side of the battery pack and alternately twisting till the plastic has some nice cracks and then applying further violence with a pair of long nose vice grip pliers you can see the control circuitry. My theory ( which is mine, and shall remain mine until dis-proven ) is that once the battery voltage drops enough the internal electronics shuts down and doesn't talk to the laptop, at which point the laptop reports "No battery present" and doesn't attempt to charge.

Anyhow more violence and the whole viscera is spread out for your friendly techno-mage to use for prognostication ( or parts B| )

More violence ensues. The connections at the battery ends are spot welded, those break easily with a set of pliers grabbing and rotating like a ham can opener (old school with a slotted key and tab on a strip that pealed out ). Generally the ends clean up well enough but you might want to grind off any sharp points left.

Popped into a smart charger and all 6 cells look great. I could charge these faster but I'm already at the charger's supply limit.

 

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Can do better..  http://www.hikinghq.net/hammock/hammock.html  Went looking to see what's being done after thinking about it a bit. I started using a hammock when hiking back in the early 1970s, pre internet, and just hadn't thought to look for others doing the same. ( I was also using a soft back pack for books, slide rules etc. back in university when everyone was carrying cases. Yep I was the weird one ). Anyhow that site has a ton of experimental and comparative info. and it turns out a few have already been trying under quilts and are in the pre-marketing stage. Kits and plans for now. What I just read hits a few of the same thoughts I had. Minimal changes to the hammock, multiple anchor points. It might be pretty easy with the old ( very cheap ) cargo net hammocks. Those things are sort of the cafe combate of hammocks, they work but leave a bit to be desired. With that wide open mesh there would be lots of places to tie to, and all you'd need is a modified bag with cord loops sewn through in a grid. Could also take the approach of making a bag with an integral hammock, then could address the fact that it would be nice to have an extra long bag underneath by actually making it that way.  I can also see a good case for a Hudson Bay blanket inside the hammock under a sleeping bag, and of course the old standard for cold weather, layers. Carrying a mass of wool blankets etc. will add up, but again what are you doing. No one is going to go walking through 1 meter deep soft snow for any distance, with or without a load. Snow shoes are a pain for long walks too, and if you are up to needing those, a sled will take the weight for packing stuff along.

Also am seeing straps for hammock anchors, makes sense and 3 meters of 2" cargo strapping , just held on by wrapping over itself, looks like a very low impact way to hang even on softwoods. Might add a velcro pad as a holder for before a load is applied.

Sometimes get in a rut just because of doing the same thing for so long. Ordered one of the new ultralight hammocks to try out, besides the old cotton ones are getting to have too many patched strings. :D

  Been in a Hammock a lot as of late.... living in the North Eastern U.S. there are no shortages of trees ... Another great forum for a hammock user is   https://www.hammockforums.net/forum/forum.php  plenty of material resource links there and lots of good ideas ....

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Faraday cages... What they are, how to make and why this isn't a big deal.

Ok, you have some backup hard drives, old but usable computers, spare radios, infrequently used test gear etc. and you'd like to store it so it will still work after a lightning strike, CME that you didn't see coming or Dr. Strangelove event. The simple way to do this is a Faraday cage. Sounds expensive doesn't it? Named for Michael Faraday, possibly the most brilliant experimental physicist in history. 

What is it? A continuous electric conductor surrounding a space. That's it! so a 45 gallon steel drum with a snap ring holding the lid on qualifies  as long as there is a good continuous contact around the whole lid, use a wire brush on a drill to remove any paint on the edge of the drum and inside the grove that fits over it. I'd expect about 40 DB of attenuation from that, maybe better if you pay attention to detail.

DB and DBm, DB is a relative number. DBm is an absolute power. Both are log scales it's just 1 DBm is defined as 1 milliwatt. The scales are Log 10 , so 10 dbm is 10 mw , 20= 100, 30=1000 ( one watt ) just think of it as the number ahead of the last zero is the number of zeros you factor in. 40 DB is an attenuation of 10,000 times and what gets through in power terms is 1/10,000 of what you started with. So a relative scale. For EMP shielding 50 or 60 would be nice, 100 is into lab work range.

ESD bags , these are conductive bags meant to shield against static electric discharge damaging electronics. As such they are also effective at reducing EMP damage. I'd expect 20 DB or more for a reasonably good bag. So ESD bagged electronics stored in a prepared steel drum should ride out anything that it physically survives. Save the bags when you get them ^_^ Lots of stuff is shipped in ESD bags now, sometimes zip lock so even water tight. I don't trust the zip lock seal to be conductive so fold over when packing.

Ammo cases. These have 2 problems, the rubber gasket isn't an electric conductor so there is a gap around the lid. The side flaps make a very nice slot antenna tuned to 4 times the wavelength of the side flap length ( and harmonics ). This can be solved with finger stock ( made to form an electrical contact across movable gaps in things like tuned cavities, very expensive spring steel with silver coating ) or conductive metal tape ( metal duct tape , for instance  http://www.amazon.com/Venture-3520CW-50yd-Aluminum-Insulation/dp/B005L6CEYI/ref=sr_1_7?ie=UTF8&qid=1450673930&sr=8-7&keywords=metal+duct+tape  

Only problem with tape is you have to re-do it every time you open things.

Galvanized trash cans. If you can find the ones with a tight fit between the lid and the can, great. Most are sort of loose fits with a latch so back to the slot antenna - lid seal problem. Tape will fix that and I also want to try a foam rubber gasket pressing metal tape against the rim. I'll get back about that once I run a few tests, but it's going to take awhile.

Tin foil... great stuff especially for small boxes wrapped up for long term storage. Like a backup hard drive or a few SD cards of things you really want to keep. A tightly wrapped pocket hard drive with a couple of layers of tin foil could easily hit 100 DB of attenuation ( 1/10,000,000,000 ) Short of a near by super nova that should be good. ( Ps if a star within 10 light years went super nova, the neutrino flux would vaporize us before we had a chance to say "What's that flash?". Forget about prepping for that one unless you have plans to move a long way off for your bug out location. )

Notice you can add things, so an ESD bag and a steel drum will produce 60 DB of attenuation, Probably more then you need and as a snap ring and a bag these are easy to use as a daily storage option. A bit of creative carpentry for drawers, shelves etc. and you should be set.

Really anything helps. That ammo case, un-modified will still do 10 db or so, and keep stuff dry, taped up and it may well be all you ever need. Filled with tin foil wrapped storage devices, chips, radios, laptops...  it's great.

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Great info as usual Gary. I'd love to sit down and pick your brain. Story time too for sure. Your right about faraday, but his name doesn't get much air time.

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Small addendum re metal matches. The cheap ones are fine at lighting and making sparks but they use a cotton wick. If you don't put them out fairly fast the wick burns away. I've just tried replacing the wick with ceramic fibre ( gasket material left over from replacing the firebox seal on my stove. I'd burned the modified match right down a few times after, as in the video.

 

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Diesel fuel , starting with veggie oil... http://chemistry.about.com/od/chemistryhowtoguide/a/makebiodiesel.htm

the process is pretty simple, for 1 litre of oil, use 200 ml of methyl hydrate and 3.5 grams of NaOH . Can substitute KOH ( so once again soak those stove wood ashes :) ) . Room temp or warmer , 200 ml of wood alcohol in mixer ( blender in the kitchen chemistry example ) slowly add 3.5 grams of lye , blend till fully dissolved, add oil , mix for  30 mins, pour into a container and let it settle for a few hours. Top is fuel, bottom is glycerine.

I haven't tried it as lamp oil but it should be worth a shot.

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Revisiting my violent destruction of dead laptop battery packs. As of right now I have over 70 fully charged 18650 Li-Ion cells and 8 dead cells and three with reduced storage. I've cycled them to measure capacity and intend to check voltage after they have sat for a month. 6 of those 8 are open and draw no current on a charge attempt, they also all came out of the same pack. The other two have internal shorts so they never really charge and what they do is gone in minutes. so basically a 90% success rate at salvaging free power storage. Most of the cells hold 2 amp hours at 4.2 volts, so the collection is about 560 watt hours of storage.

When I started this I was hoping for maybe 20% salvage and expecting mostly weakened cells, this is wildly better. One cell in a "power bank" USB charger is enough to run my cell phone for a day. They will directly replace some triple AA packs in flashlights ( and run brighter and longer then the original ). I've also got a pile of control cards with useful chips, crystals, FETs , resistors, caps, inductors, RTDs and handy metal bus strips. Not too shabby for free.

If anyone else is interested in this, a few observations and cautions. Be careful breaking the welds loose, ideally use small pliers to grab and roll the strips back, and a knife to pry. Be careful not to short across batteries, these things can burn a hole in your knife blade ( use a cheap one you don't like ). By all means buy a good charger made for the job. Mine reads, charging current, cell voltage, total amount of charge or discharge and time. It will also discharge cells at a controlled rate for testing.

If the cell is totally dead ( as in 0.1 volts ) the charger doesn't even start, so take a 12 volt source, a 12 volt light and put the suspect cell in backwards ( + into the + end ). If the light comes on the cell isn't open, if you leave it in for 5 mins it will likely go into the charger and work. The series light acts as a current limiter so you will not damage anything.

Used as a straight power source, and individual cells getting charged in a charger is safe, but don't just treat these like lead acid batteries or NiMH , over charging is a bad idea ( as in fire hazard bad ) so if they are going into a dedicated system, like a solar collector, design a charge controller and probably program a microprocessor to shut off any charging once the cells are fully charged.

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And when you are working on unknown Li-Ion cells make sure you have a quick way to throw them out the window as they suddenly can burst into flames. That is one reason why some airlines prohibit them onboard airplanes.

As Gary_Gough said, make sure you have a good charger and not a 2-dollar one as that increases the risks dramatically.

 

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49 minutes ago, Flip said:

And when you are working on unknown Li-Ion cells make sure you have a quick way to throw them out the window as they suddenly can burst into flames. That is one reason why some airlines prohibit them onboard airplanes.

As Gary_Gough said, make sure you have a good charger and not a 2-dollar one as that increases the risks dramatically.

 

I keep a metal 1 Kg coffee can with snap on air tight lid nearby for sharp metal - broken glass - trash, toxic volatile chemical surprises and unexpected fires. Disposable and still enough to contain things while they are being carried outside. A couple of cm of kitty litter on the bottom will keep the heat transfer down too, and absorb small amounts of acid if you spill some while doing metal assays. Should be doing that in a well vented space anyhow ( red fuming nitric is hard on everything ). Preferably out by the forge / foundry. But, as I have been known to mix small amounts of rocket fuel on the wood stove, I can't really hold myself up as a shining example of industrial safety. :P 

Proper Li-Ion chargers can start with a 50 ma conditioning charge, then current limited to 1/2 the rated storage for 2-4 hours and voltage limited to 4.2 volts for the duration, if they don't reach 4.2 volts in that time, or get too hot, they should be recycled not reused. If they self discharge get rid of them. Most of the good chargers look for a voltage from the cell to start. Good reason for that, a totally dead cell could have self discharged and so isn't safe to charge. Manually doing a conditioning charge also means knowing that you need to pay attention. The cell should show a couple of volts in a fairly short time ( minute or two ) and hold that charge. Don't rush it esp. if you haven't charged a cell before. I like to limit the charge current to 1/4 of the rated capacity and let it take longer. The way laptop packs work, they run two or three cells in parallel then three sets of those in series and monitor the voltage across each set, any one cell self discharging forces a full shutdown. ( discharges the cells it's // with and then the low voltage across that set errors out the full pack ). Of course a battery that was fully discharged in error looks just like one that was self discharged to the charger. As an example, I got a laptop that had a shorted power button and so was always over riding the low power shutdown until there was no charge left ( at all < .5 volts on each cell ) 9 cells that all needed pre-conditioning to start and then all took a full charge and tested fine.

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Hi Gary, just a quick word on the hammock suspension straps. I use approx. 1x meter x  2inch wide seat belt webbing and tie a tape knot in it. (a granny knot on web and another through it) Then put it around tree, feed it through itself, and clip with a carabineer to hammock. Doesn't slip down trunk.

Heard a story 3rd hand many years ago about some climbers up high in the Mountains. Didn't put their stove in sleeping bag with them O/night. Those Blue sealed canisters that have to be punctured. you know the ones.  

   Anyway, they couldn't get it to ignite because the gas had frozen solid. So removed the cylinder from stove. OK so far. Other guy had a new unpierced cylinder is his s/bag so retrieved it and put into stove and started cooking a brew.

Well I'm sure you can work out what happened next..

Ambient temp. inside tent increased, therefore thawing out gas in first cylinder. Hmm.

Almighty flash/bang and tent and sleeping bags shredded. Others that came to rescue said it looked like it was snowing with all the goosedown floating down from sky.

Nobody hurt ,other than pride thank goodness.:/

Lesson to be learned though..

Edited by kiwitransient
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39 minutes ago, kiwitransient said:

Hi Gary, just a quick word on the hammock suspension straps. I use approx. 1x meter x  2inch wide seat belt webbing and tie a tape knot in it. (a granny knot on web and another through it) Then put it around tree, feed it through itself, and clip with a carabineer to hammock. Doesn't slip down trunk.

Nice. I hadn't thought about seat belts ( getting old dagnabit ). Great idea and I'm sure I have 20 or so spare in the inventory stockpile ( ok junk yard ). I was thinking of 2 inch tow strap but the belts would be more flexable ( and I could play with the hardware too ).

44 minutes ago, kiwitransient said:

Heard a story 3rd hand many years ago about some climbers up high in the Mountains. Didn't put their stove in sleeping bag with them O/night. Those Blue sealed canisters that have to be punctured. you know the ones.  

   Anyway, they couldn't get it to ignite because the gas had frozen solid. So removed the cylinder from stove. OK so far. Other guy had a new unpierced cylinder is his s/bag so retrieved it and put into stove and started cooking a brew.

Well I'm sure you can work out what happened next..

Ambient temp. inside tent increased, therefore thawing out gas in first cylinder. Hmm.

Almighty flash/bang and tent and sleeping bags shredded. Others that came to rescue said it looked like it was snowing with all the goosedown floating down from sky.

Nobody hurt ,other than pride thank goodness.:/

Lesson to be learned though..

Back up this thread a bit I posted a graph of vapour pressure vs temperature for propane and butane mixes. Those camp cylinders are basically butane so 0 pressure at 0 C. A little playing I just did today. Pocket stove for those are $10 and include sparker. Nice design but there is that whole issue of it gets allot colder then 0 around here. -30 and you will really miss having a fire. So I decided to see how they'd work on propane. Made an adaptor from an old propane torch, spun the burner onto that and controller the flame with the valve on my converter. Worked well. So a second option and one that can be pulled apart and stowed between uses. No pictures right now ( I'm at work ). Of course my converter is almost as big as the "stove" oh well.

http://www.amazon.ca/gp/product/B00AXV1YGK

 

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Using a short style propane tank, on a hard totally level surface ( top of the wood stove ), the 13 inch cast iron skillet was right at it's limits. Tended to flex the arms torsionally and of course had to pay attention to keep the pan centred, so I'd say best to use smaller and lighter stuff. Then again who hikes with cast iron pots and pans? :P Fried up some onions and eggs. If I was using it outside right now I'd probably dig the tank into a snow bank for stability.

I was thinking of this as a smaller replacement for the single burner propane stove in my car emergency pack. Bulky and an awkward shape. I'm more likely to be boiling a litre of water and making soup or coffee in the car, so small is fine. This is a good match for the aluminum "camper cookware" kit.

Edited by Gary_Gough
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If you want to score some incredibly cheap pots/pans and bowls etc. (stainless steel) go to a shop that specialises in supplying to Indian families. Real good quality LIGHTWEIGHT kit for VERY cheap. e.g. $3 for a pot with lid. NOT a misprint.

#555 brand. Bought some when last in Fiji. Indian people prefer to eat from Stainless steel. Must ask why next time. For that price, one can afford to have a complete set in all BOB gear without breaking the budget.

I've seen similar stuff in other stores for 10-20x price.

You will only have to buy a alloy pot lid lifter. Those things that look like a set of vice grips..

Going to get some more when I go back this season.

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Good point..

An Indian friend explained to me once that Curries, especially the Hot Pickled Chutneys,

can stain many plastics and ceramics and enamels and are corrosive..

a thought..

:)

 

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Definitely agree.  Indian, Pan-Asian and Latin-American markets can be a treasure trove for inexpensive gear.

I have been getting heavyweight aluminum 4 inch diameter/5 inch tall stock pots with lids for about $6US here at a Mexican supermarket.  Just add a folding Esbit stove, some fuel tabs, tea bags, chicken bouillion packets, pastina pasta, a food bar and a couple fire sources (lighter and a ferro rod) and a cheap folding knife, lash on the lid with some paracord, and you have an instant gift for family members who might need a gentle introduction to being prepared for emergencies.

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Thanks Wyzyrd, that is a great idea.

Bundle that stuff up and give to people we care about, who perhaps wouldn't do it by themselves. Maybe some candles as well. Could actually get quite a list going for a few $.

Care and share..

Nice idea.

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I love Indian food Dan. Being Vege. it just seems to blend in with my lifestyle. Plus the Indian People I have met in Fiji are just great. Spend time with a Family there and Diwali is a special night. Festival of light.

When the Ladies get dressed up in those Sari's, they really are stunning !

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This is probably one of those horribly obvious things, but here is a photo spread of adding an eyelet to a fabric belt without weakening it at all. Should work for canvas or any woven material with a bit of give. Poly tarps or leather pretty much has to get a hole punched.

Anyhow, tools, pen shoved through from the front, eyelet pushed onto the pen and pushed through the fabric ( hole would close before you could insert otherwise ) Crimped, then second eyelet pushed through from the front and crimped. View from the back. I do the double to keep sharp edges down, not strictly needed but shove the pen from the back if you only want a single. 

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Another note on Li-Ion cells. I'm finding some that will take a full charge, hold it well, but never stop charging at 4.2 volts. On doing a bit more research I've found out Mil Spec chargers max out at 3.9 volts and result in longer battery life. Also there are a few variations of Li-Ion chemistry which probably explains the problematic cells, they came as sets. So far about 12 out of 200 cells ( ok I asked a friend running a repair shop if he had any dead packs , 20 Kg later .... ) about another 90 to retrieve.  Only have 10 cells that are open or self discharge. This is a crazy ratio in favour of good batteries. About 1/2 are 2,000 mAH or better ( a few measure over 2500 mAH storage on a discharge test ) The cell that came with a $65.00 flashlight was 1,200. Nothing shabby about these.

At these prices, I have now got USB chargers in my packs ( $5.00 each )that use one 18650 cell and a small case with an extra 6 precharged hi capacity cells. Changing to flashlights that will use them too. Shelf life ... well so far, other then a few truely defective cells, I'm not seeing any drop below 3.8 volts. Track record using Li-Ion batteries , I have a few 15 year old cells that ended up just being stored as nothing used them ( "C" size ) rated 3.6 volts, still measure 3.8 volts.

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Little project that I knew was pushing things. 100 watt LED work light. The light it's self works great, bolted to a 7cm cube of aluminum heatsink. Voltage booster-regulator almost gets up to 33 volts and then the smoke starts rising out of the battery packs. 8 Li-Ion in series, and the batteries are fine too, I'm melting the wires on the battery packs ( and springs and rivets ). Thought they looked a little light for the 3 amps I'm drawing xD Was intending on 32 batteries anyhow to get some run time. Anyhow even somewhat short of full power this thing is like a portable yard light, just need to spread the load across more batteries B|

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