Good morning, CodeTalker here, and welcome to SMHRB, the NEW and IMPROVED (not really) version, where we get together to - well, whatever, as long as it has to do with home repair and anything even remotely to do with DIY. So set yourself down a spell, grab your cuppa joe, poke fun at me, relax and read some of our exchanges, or even jump in with a problem looking for answers, or your own experiences - after the dKos curl, of course.
I have to admit, finding out I'm the one opening the shop on Friday night at 11:30 isn't my idea of fun, but at least I have something to open with... so, follow me and watch the old guy fall flat on his face...
BTW - this one's for my friend Claude, who has waited a long time for this diary.
(And Claude, I hope things are going better for you now - you and Eve are in my thoughts, every single day!)
Today I'll share my "secret" for rejuvenating old Ni-Cad batteries, such as those found in hand-vacs, tools, and other portable battery-powered devices. I did two DustBuster battery packs this week, and both nearly doubled in suction power (motor speed) and working time. I've also done it to drill packs, and even individual batteries, over the years, and it's helped every single time - even with a few 10 year old batteries! (although don't expect a long life from any that are old - typical "useable" rechargeable battery life is usually between 3-5 years from the date of manufacture, NOT date of first use!)
It's pretty simple, and anyone with some know-how can do it - I do it because I just hate to throw out a perfectly good unit just because the packs don't hold a charge anymore, or I can't afford to replace or rebuild them - and yes, there are places that will rebuild packs, or even upgrade old Ni-Cads to Li-Ion technology; for that, Google is my friend! It ain't cheap for a lot of them, but if you can't replace a dead pack for a good tool, hey - why not?
First, a caveat - this is kinda dangerous, with a lower-case "k" and "d". Ni-Cad batteries CAN, and DO, explode - NOT like an M80, but more of a "pop." It's happened to me, and it can happen to YOU, so if you're not inclined to live on the edge, please don't bother trying this at home. OTOH, if you have favorite tools or devices that you can't get battery packs for any longer, read on - but BE CAREFUL! YMMV, and I take NO responsibility for your actions, of course. (OTOH, I've done this a number of times already, so it CAN be done safely!)
The principle is simple, and comes with its' own caveat - this ONLY works on Ni-Cads! Don't try it with ANY other type of battery - it will either blow them up or kill them! You have been warned. Ni-Cad - OK. ALL other types? NO WAY!!! Don't even TRY it!
OK, all you need is a voltmeter, a sacrificial battery or battery pack that needs "re-juicin", and a car battery charger - the 12 volt kind, preferably a low-amp unit, but NOT a trickle charger (if you don't know what these terms mean, this is NOT for you, BTW!). Mine has 3 settings, 2A, 10A, and "Boost", which can briefly hit 50A or so. I only use the 2A setting - any more and I think you just risk killing your Ni-Cad more quickly. The basic theory is that the material inside that stores the charge is granulated, and as time goes on the granules grow larger, decreasing surface area and limiting the amount of charge the battery can hold. Well, it turns out that a jolt of juice LARGER THAN the voltage of the battery "breaks down" or shatters those granules into smaller grains, increasing their surface area, and allowing each to hold more of a charge! Simple, right?
What this also means is that we need to be sure we're not trying to juice an 18V pack from a 12V charger - it simply won't work; we need to hit them with MORE voltage than they are rated at, not less. What we really need to do is open the battery pack and get at the individual batteries inside, so we can hit them one at a time - the best way to juice them - with your 12V zapping each (nominal) 1.5V battery, one by one. I've tried doing some old 7-9V drill packs with my 12V charger, with only fair results; hitting the individual batteries works much better, and it's worth the time and effort to OPEN THE PACK to get at them.
This is where I have fun; first, I study the battery pack - nearly every one is different, but most of them have a way inside to get at the batteries - did you know that almost all battery packs are just groups of AA, AAA, C, or D batteries, wired in series, with some components to help regulate the charge cycle? Even the lowly 9V battery is just 6 AAA batteries in a case - I took one apart to see for myself. (6x1.5V=9V) If you do that too, rip apart one that's already used up, ok? Your laptop battery? Same thing - a bunch of AA batteries stacked in series. That 18V power drill? 12-C size batteries! (12x1.5V=18V) Pretty simple, indeed. (And yes, for the scientists here, I am aware that most rechargeables only put out 1.2-1.4V or so, not the full 1.5V of an alkaline, for example; but my math isn't meant to be exact, OK, so no flames over it, please, it's close enough for this.)
That's really the hard part, and I can't help you with it - but most battery packs DO open somehow, although I've come across several that were glued shut, like for laptops - of course I've cut them open too, who do you think I am? (Curious George got nuttin on me!) But, the great part is, tools and devices like DustBusters - well, they come apart with screws for the most part - talk about makin it easy on us! So, take your time, look the case over carefully, and you'll probably discover how to open it and free all that juicy stacked battery goodness inside - which you'll need access to for the next step, which is - TESTING VOLTAGES.
You see, IME, most packs don't lose ALL the batteries at the same time; in fact, in every one I've opened so far, I've found ONE, maybe TWO, weak or nearly dead batteries, and a bunch of good ones. But one bad apple, etc - and a dead battery in series kills the series! So your job is to find a way to test each battery, one at a time, by touching the voltmeter leads to each battery at each end; that is, red (or positive) lead to the + end, the end with a little "button", since they aren't marked with + and -... and the black (or negative) lead to the "can" or "flat" end, the one that has NO button. It helps to mark each one with say, a dot for the first one, 2 dots for the next, and so on, and record the voltages you get, which should be in the 1.1V to 1.2V area for most "weak" batteries, or lower for really sad ones. OTOH, a "dead" battery will often register as low as 0.5V, maybe even lower - and I have to add, when they are that low, this may not work, which also means you have nothing to lose.
Once you have all of the battery voltages tested and recorded, pick the lowest ones, and mark them. It also helps to indicate which end is which, because next you'll take the leads from your car battery charger (You DID plug it in, right? And be careful to not let the leads touch each other and make big sparks, right? Good!), and you're going to HOLD one on the appropriate end (black/negative to -, red/positive to +) of EACH individual battery, and TAP TAP TAP the other one to the other end, between 12 and 15 times, rest 5 seconds, and repeat at least once - you shouldn't need much more than that; and in any case, never keep going if the battery gets very warm! I personally like to hold the - end on, and tap the + end, but it will depend on how well you can actually GET to the ends, as you'll see when you open a case - some are sealed in a plastic "liner" that you'll need to cut small flaps in to get to the metal battery surfaces, for example. Another thing you'll encounter is that series batteries are welded together by thin metal strips, so you'll have to keep in mind that one metal strip goes between one battery's POSITIVE end and the next one's NEGATIVE end, so that strip will serve as BOTH + and - connections to tap on, depending on the other end - see?
Got it so far? It really IS simple -even I figured out how to do it correctly, so anyone else can too. Look, a pack is a SERIES of single batteries, connected end to end, + to -, and then wired to a circuit for purposes of controlling charging and output source. Our job is to find the ends of EACH battery and connect to it - sometimes I stick a screwdriver or other tool in between batteries for the purpose of connecting one charger lead to that end, because my charger clamps won't fit between the stacked batteries - and then TAP TAP TAP the other lead on the other end, making sure you get a spark each time and NOT holding it on the battery for more than a tap. Do each of the weak batteries at least; you can do ALL of the batteries if you want, and I have, but if you got a "good" voltage reading from some of them you probably don't need to jolt those. I also like to test the ones I juice afterwards, to make sure that initial voltage has gone UP from the initial reading - if not, it's dead, and no amount of juicin will revive it.
Make sense? seriously, if you're not sure by now, I can't explain it in a way that will make any more sense, so maybe you'd better pass on this trick. Or get someone else to do it for you!
But for those of us adventurous enough to try, the joy of saving old battery packs, and the tools that they power, is worth it! I know it is for me...
I'll be around on and off today if you have any questions. I don't have pictures, but you CAN Google those - there are a number of sites that explain this trick AND have pics or even video that show how online - I'm just maybe a bit more thorough than most of them - and maybe a bit safer!
There's a lot more I could add, such as how to charge them the first time, how to "train" and "re-train" a battery, and that Ni-Cads (and car batteries) should never be run completely dead, but it's OK, or even good sometimes, with newer types like Li-Ion for laptops and cell phones, but maybe we could save all that for another time?
Whew! that was a lot to cobble at the last minute, but it IS for Claude, so I don't mind.
As for the rest of today, the floor is open, my coffee is still hot, so take it away, fellow Kossaks!