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ArcticMyst Security by Avery

First Build First Thread

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It really depends. If it quit suddenly and you get it open and the cells are still above 2.8v or so each. They're probably still good. If they're just below 2.8, they might could still be resurrected. Much lower than that, after a year, and they're probably trash.

Just be careful harvesting them and don't puncture one, or short the pack or any cells out.
 





Tux

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Alright I just bought a pair of protected 18650s a charger for them (wf-139) and two Li-ion battery holders (the one you recomended me)

All of this starting to add up in $, but I guess your first build is always the most expensive.
So far I've bought:
PHR diode pre installed in aixiz housing $20
safety glasses $50
2 batteies $20
battery charger $15
2 li ion battery holders $30
Total spent:$142!!!!
Some of this stuff had free shiping and others screwed me over with shipping.

I know I got protected batteries and 2 expensive protective battery holders, its bacase Im looking to use my old laptot batteries. Yeah Im going to give it a try, that is extracting the Li ion batteries form a Dell battery pack. I cracked open a very old laptop's battery pack yesterday for practice, its not to bad.
 
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That battery holder I pointed you to holds two 18650's in series. You should have only needed one of them for this build.

The safety goggles, batteries and charger are hard to consider costs though because they're stuff you can use on future builds. You'll find the more stuff you get parts wise, the faster and cheaper future builds get as far as having to buy stuff, because you'll already have parts on hand.

Looks like you should pretty much have everything you need on the way now though.
 

Tux

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Yeah the reason why I bought to battery holders was because I figured the laptop battery pack will have moe than just 2 batteries. By buying two protected battery holders I dont have to wait for shipping for a battery holder for my next build. I probably wont even need to use a protected battery holder because the two batteries I bought are protected.

Its gona be a while untill I will start recieving these parts, but the status on the LD w/ the aixiz house is that it has already been shipped, its possible I might get it sometime this week. I will stop by radio shack this week to pick up a new lm317 a project box and several diodes for testing out my driver. Is it ok to continue and test my driver with a 9v battery. I understand the 9v and the 18650s batteries will have differences, but I just know when I get the LD in the mail I will rip it open and want to play with it right away.
 
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In a pinch, you can scavenge a laptop battery pack. They'll have non-protected 18650's in them but usually people don't get rid of good packs so most of these cells will have fairly low capacity.:D)

Laptop (or power-tool) battery packs are an odd choice. Often, a single cell in the pack fails or leaks. The others still have quite a bit of life left in them, but they're just thrown away. You could even scavenge old battery packs from the recycle box at a local hardware or home-improvement store or a "Batteries Plus" retail outlet. The stuff that leaks out is not good for you or your skin.

Charging them will be odd -- you can't use the original power supply, since one of the cells (and likely any special circuitry inside the case) is gone. Also, laptops have an internal charging/regulator circuit that you won't have.

You'll have to use an ordinary charger; get one that matches the cell chemistry (Li-ion, Ni-Mh, Li-Poly, etc.). I've seen a lot of warnings -- the general rule of thumb I follow is that if the battery doesn't get very warm while you charge it, go for it. Too hot = explosion or a chemical fire (literally). Never charge more than 16 hours, since you're working with non-standard configurations and can't trust features that prevent over-charging.

NEVER mix cell types or sizes. Don't even think about it. If you're still tempted, read up on "battery internal resistance" -- yeah, batteries have resistance, each type has different characteristics, and their resistance changes as they discharge.

These cells will have very few markings, since they're packaged for industrial use, not retail. The plastic case label will usually tell you what kind they are.

Treat them with respect. Shorting an alkaline battery will run it down in a few minutes. Shorting a rechargeable battery will make it red-hot in seconds, and then it will explode. They can develop 10 times the current of an alkaline, and dump 10 amps all at once.

Just to be certain, measure each cell's voltage with a meter (I like Elenco 1000 and 1750 multimeters - $15-$25, fused, lots of features). It should read around 1.20 to 1.30 volts DC (rated 1.25VDC) -- charge them all and pick out the best ones. Some will hold a charge longer than the others, so the weakest cell determines your running time.

The cells have metal tabs or wires spot-welded to the ends. This makes them easy to solder to a wire. Some look sort of like an oversize lipstick. They're often a size you've never seen before. Most will not fit into any charger you own, so you'll have to wire them in. Alligator clips (they still sell those at Radio Shack) will make that easy, but color-code everything so you connect it properly every time. If you wish, dab some red nail polish on all the + ends and connect red clips and wire. Black is negative (the 'bottom' end of a battery).

Recycle all old batteries at any hardware or home-improvement store. Do NOT put them in the trash.

If you prefer a 12 volt DC supply that plugs into the wall, try Mouser.com or AllElectronics.com I've read to avoid 'switching' type power supplies, as they can issue spikes that can fry your diode. But if you have a good regulator and a spare diode or two, maybe you'll get lucky and find one from an old printer or ???. Typically, switching supplies have an AC cord going to a rectangular box (a brick in the middle of two cords), while transformer supplies (OK) are a block that hangs right on to the AC outlet.
 

Tux

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WoW Phillip nice post, no offense but this is kinda of an old thread, and pretty random for your first post lol. But thanks anyways.

Kinda off topic, but Im looking for a way to get around 24DC 10A without the use of batteries, any suggestions.
 
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Im looking for a way to get around 24DC 10A without the use of batteries, any suggestions.

You could get a pair of 12V 10A power supplies and connect them in series.

ALL Electronics has a 12V 9.1A for $17 each +S&H but that's a PEAK rating, not a steady rating (other sources show it as 6.5A steady, so a quad setup - a pair in series with another pair in parallel to that -- would give you 24V and 13A for as long as you want. If you're powering a laser, how long will you use it before switching it off, anyway?) That would cost about $85 for steady use, or $45 for intermittent use. Link: 12VDC 9.1A SWITCHING POWER SUPPLY | AllElectronics.com
but it doesn't have a case around it. You could mount them bottom-to-bottom on a piece of wood and fit the whole shebang inside one vented case, or just make a clunky wooden enclosure and punch lots of holes in it. Input is 100-240VAC 50/60Hz so they should work almost anywhere in the world. Make sure any mounting hardware is electrically isolated.

The ALL photo suggests these were intended for a commercial installation -- I don't see matching Molex plugs to connect them up. At high current, over time, Molex connector pins (the flexy half that mates against the pin on the PC board) will get too hot and eventually melt/burn the plastic anyway (I've seen it happen, it's a mess since the flexy metal gets burnt up, too).

If I were you, I'd use a pair of needle-nose pliers to carefully bend out the top half of the pins I want (and/or nippers to clip off any unused pins nearby ) and solder heavy wire directly to them. It looks like there's a 2-pin 120VAC input plug and a multi-pin DC output plug. They don't mention a 'sense' or 'feedback' function to finely regulate the output, which you probably don't need anyway (to compensate for voltage loss in the wiring) so I'm guessing many of the pins are duplicates or dummies. If they're dupes, try to use both for your connector wire. I'd also check the solder connections on the pins at the PC board to be certain they put enough solder on the joint and formed a good meniscus (they often don't).

I'd invest in a 12VDC PC fan to keep the whole thing cool -- just pull power from one of the supplies. Power supplies are not designed to run constantly at full power, and it sounds like that's what you're planning to do. Any heatsink that's too hot to touch (120 degrees F) is too hot. As always, be certain the heatsink is not electrically hot before touching it, too. (Check with a voltmeter from heatsink to circuit ground and also to an earth ground.)

If you don't have a voltmeter, you should have one. I like the Elenco M-1750, about $33 from Amazon.com (AC/DC/Ohms/Continuity/Frequency/Capacitance/Gain) Link:
Amazon.com: Elenco - Digital Mulitmeter with 3 1/2 Digit Display: Toys & Games

Otherwise, Mouser has 24V 10A supplies that are ready to go, but they start at over $100. Link:
Linear & Switching Power Supplies

You could build a conventional power supply with a transformer and diodes, capacitors, regulator, etc., but a 10A transformer would be very heavy and a 24VDC 10A regulator would be pricey. ALL has a 24V 5A transformer for $30, so you'd need two, so it would be nearly $70 just for the transformers (unless you can find some high-amp 12's or 24's just laying around -- not very likely). 30V-35V large capacitors (you have to allow some tolerance) are expensive, too, unless you can find a surplus supply. Large electrolytic capacitors dry out over the years and must be replaced. If you don't know how to build power supplies (make adjustments for ripple, surges, etc.) this is probably not a good idea.

If you want to go totally steampunk on us, you could connect a scavenged electric motor from an old washing machine using belts and pulleys to a pair of 12VDC junkyard car/truck alternators wired in series. They'd load 10A without breaking a sweat if they spun fast enough, self-regulate to 13.5V each (so 27VDC out) over a wide range of RPM's, possibly be pretty cheap, but not very small, safe, portable or quiet. Check for AC ripple with a DVM on low AC range.

You could also use industrial-grade rectifiers they usually use in hi-lo lift trucks and a simple voltage divider to scale 110VAC down to around 20VAC and convert to DC, but if you don't know what that means, you're probably in over your head. Possibly cheap, but requires serious safety considerations.
 
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Duh. I just looked at your link. Looks like a guy in Hong Kong has more to sell on eBay. $50 plus any customs duty. Easy hookup, made in China (most everything is) and rated 14A but doesn't mention whether that's continuous or intermittent, so I'm guessing intermittent, and about 10A continuous.
 
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P.S. On your DeLorean (NICE!) there's a cable pair under the front end that powers the radiator's cooling fan. Stupidly, they put a plug/jack combo right in the middle of the cable run, where it droops down and collects water/oil from the road in the plug. When that plug gets dirty, the fan stops so the engine overheats and blows up. If that were my car, I'd protect that tiny, vulnerable spot.

Ol' Mr. D learned a thing or two about planned obsolescence from Detroit.
 
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you could go to a real electronics surplus store. most cities have them. you could pick up a 120vac to 24ac transformer for really cheap then get bridge rectifier from radio shack.

i''m kind of a procrastinator, but if you are interested i can check to see what my local surplus electrtonics store has on my way home one of these days. i don't know where you are located or if shipping is worth it. but it shouldnt way mor that a few pounds.

michael
 
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P.S. On your DeLorean (NICE!) there's a cable pair under the front end that powers the radiator's cooling fan. Stupidly, they put a plug/jack combo right in the middle of the cable run, where it droops down and collects water/oil from the road in the plug. When that plug gets dirty, the fan stops so the engine overheats and blows up. If that were my car, I'd protect that tiny, vulnerable spot.

Ol' Mr. D learned a thing or two about planned obsolescence from Detroit.

You are correct about the fans being a weakness. However your wrong about the reason. The connection you mention sits on top of the frame. There is no possible way for it to 'droop down' The real problem with the fan system is the fan fail relay, which detects that the fans aren't running when they should by current sensing. The fan fail relays were underrated and tended to melt internally. However the fix for this has been on the market for decades.

Also.. if you kill an engine by overheating.. you don't need to be driving a delorean... or any other car for that matter. You'll notice a severe loss of power before it gets to the point any major damage is done.. plus there's the fact that the temp gauge will be PEGGED....

Besides, it would only be a problem when sitting still. when moving, airflow over the car moves enough air for cooling. Just like any other car. Radiatior fans only really do anything at slow speeds or sitting still.
 




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