Super-simple DIY charger for NiMh button cells.

[@bruce1164]

I've been an electronic technician for almost thirty years and I can tell when someone knows what they are doing, and when they don't. Big Clive is an expert at electronics and especially at soldering. I haven't seen too many people do one handed soldering. It took me awhile to learn this skill. One suggestion for the heat shrink that is too small. Take a pair of needle nose pliers and stretch it by putting them inside the heat shrink. You can stretch it pretty far without it ripping.

[@SiskinOnUTube]

I stretch heatshrink all the time. I'm not an expert though.

[@madbstard1]

Agree with comment about the soldering skill. One of his older videos he gives a tutorial on how to solder. Keep thinking about showing it to a tech skills teacher here - all he teaches is carry solder on tip to the component and blob it on. Just really shoddy way to work. And he is teaching loads of kids to do this :( We need Clive to do school demos!

[@yuriismywaifu203]

I have stretched heat shrink quite a lot. It's the only way to get the right size over laptop charger plugs.

[@thehappylittlefoxakabenji8154]

bruce 1164 I agree I am by no means an expert on the theory and maths involved in electronics but I am learning a lot from Clive and I am quite a dab hand at soldering in particular small stuff even holding the component underneath with a finger whilst applying solder in one hand and the iron in the other hand you soon learn to make a quick solder joint one other thing there is a tool for applying rubber sleeves with three prongs cant remember the name of it though only the name one of our sales reps gave it said it was good for loosening tight ! *****

[@v8snail]

+thehappylittlefox aka benji I ran out of breath reading that. . .

[@MatthewHendersonn]

Truly the Bob Ross of engineering; I appreciate that you leave mistakes and hiccups in the videos.

[@jerome_morrow]

For these non-standard shape NiMH batteries, I charge them with my usual mains AA/AAA NiMH charger. I connect up the relevant terminals using crocodile clip cables with small neodymium magnets to bridge the contact surfaces. Works well.

[@BlackCat-qm3sj]

Hey I made a battery pack that is 24v with nimh rechargeable AAA 1000mah batteries but wondering how I can charge them

[@BlackCat-qm3sj]

I'm just making a battery pack just for tests

[@KuntalGhosh]

Just use a constant current and voltage powersupply and set it to the sum of your max charging voltage and current.

[@stevesquire7878]

Thankyou Clive. I have put together a 5 button cell charger as you demonstrated plus a single cell charger and they both work flawlessly. Many thanks. Religiously watch your channel

[@DogsBAwesome]

Who needs ASMR when you have big Clive.

[@Azryu09]

Agreed, the Bob Ross of electronics

[@TheLinkoln18]

brian whittle Thwack thwack thwack thwack thwack... I know exactly what you mean..

[@D4MexicanStaringFrog]

He absolutely is.

[@girlsdrinkfeck]

ASMR is bullshit anyway ,a placebo made up by tumblr fans and vegans and feminists with rings in their septums

[@danielkerr4100]

girlsdrinkfeck it's some creepy weird shit lol I found it last week I wondered wtf is going on adults talking quietly lol weird

[@lasersbee]

14:22 The professionalism and quality of work is in the details...;)

[@JerryEricsson]

You know the best thing I ever learned from watching your videos is that double tin and flow method of connecting wires. Man does that work great! and when I think I may have a problem, I add a touch of flux from a flux pen (another item I learned existed from watching your videos!)

[@ronniepirtlejr2606]

Big Clive would be a good guy to have in your group after an apocalyptic war. No easy working computers or machines or easy anything. Only true Tradesman and Craftsman with knowledge could make things out of spare parts. Big Clive could fix or reverse engineer just about anything!

[@bigclivedotcom]

I'd be in my element in that environment. I'd make lights, power sources and useful gadgets out of junk.

[@ilaril]

Thank you for your informative videos! Even though I can't use this knowledge that well, if at all, I like to learn new things. Plus you are like the Bob Ross of electronic stuff. I can just listen you go all day about anything. Thank You.

[@johanponin1360]

I appreciate these kind of videos much more than the disassembly ones.

[@TATICMOOR]

I love these build it yourself vlogs by BCDC and here we have a nice simple charger circuit to build. If one glues the connectors together along the edge of another to make a block terminal. Hopefully, the gap between the plugged-in cells will then be great enough not to have the cells to short circuit against each other. One could also glue the plugs to a short piece of acrylic sheet or a small plastic box to house the charging loom, with a reasonable gap between each plug so the cells don't touch when inserting them to charge. This vlog is from 2017 and with a lot of people owning 3D printers, it is simple enough to design and print a dedicated instrument box for oneself.

[@evanpapp93]

clive you are the bob ross of electronics! GREAT vids!

[@ryulien]

Your soldering skills are amazing and so graceful to watch! Love the videos!

[@therealjammit]

This is a way to test small NiMh batteries. 1) Get one of those single cell travel alarm clocks that have actual hands (nothing digital). 2) Add wires to the battery terminals. 3) Add an appropriate load resistor to the wires in parallel with a battery socket. 4) Set the clock to 12:00 and add a charged battery. When the battery dies you can read the clock and see how many hours it ran under load. If it ran for ten hours with a 10ma load that means the battery had a 100ma hour rating.

[@endofthebeginning7648]

Jammit Timmaj I think the point of these exercises is to actually make something rather than buy something of the shelf and in doing so learn a little bit of electronics on the way.

[@therealjammit]

That's odd. I thumb'ed up the video and I don't even remember seeing it. That video is exactly what I was thinking about.

[@therealjammit]

That's the thing about those cheap clocks. They don't run slow before they stop. They just stop.

[@TheSpotify95]

I'm sure BC used a similar setup on his alkaline battery test. If I knew what resistor etc to use, I'd do this, since I have a few clock mechanisms lying around. And I have also considered an Imax B6 so I can also charge Li-Ion 18650, and Li-Po, but a genuine one off Amazon is about £47 (I'm not buying one that doesn't have the authenticity tab on the bottom of it, as it could be a fake).

[@therealjammit]

spotify95 the load resistor is easy. You can ignore the clock current because it's so small. A 1.25 ohm resistor will draw 1 amp. A 12.5 ohm resistor draws 100 MA and a 125 ohm resistor draws about 10ma. NiCd and NiMh batteries aren't perfect and a close guess is normally good enough.

[@BenjaminEsposti]

+bigclivedotcom Clive, I have a little tip for you (and anyone else who reads this comment ... hopefully, lol). If you're soldering wires to resistors or other components, you can leave the component leg a little longer so that it overlaps the wire's insulation. The purpose is that, when shrink-wrapped, this will reinforce the wire connection and reduce any bending forces on those thin, fragile wire strands! :) Even better, overlap the wires with the component itself. That will prevent broken component legs. :D (Though it does make the whole thing thicker.) P.S. I know exactly what you mean about putting the iron close to your fingers. I do the same, and it's rare for me to get a burn. (Usually when I do get burns, I get them from touching components that haven't cooled down enough. XD)

[@EvenTheDogAgrees]

Thanks for the helpful pointers. I never considered doing it the way you describe, since it always seemed "wrong" to not cut the pins to length. But when the result will be shrinkwrapped, it makes sense. Especially overlapping the component with the wires, which, if I understand you correctly means soldering the wire to the "opposite" leg in the "reverse" direction, right?

[@bradleymorgan8223]

clive is so graceful with the soldering iron... i aspire to that level of confidence

[@hobbified]

You don't have much in the way of catchphrases, but I've noticed "it's all gone horribly wrong already" is one.

[@thatsunpossible312]

Take it to bits. Fresh, juicy solder. Aaaalllrlight.

[@electromin2716]

"I'm not 100% sure".

[@Anvilshock]

"They go very well together." "I like this. I like this a lot." "Spudger." "And that's fundamentally it!"

[@positivemelon7578]

That's odd..

[@SonOfFurzehatt]

"It's rather stylish."

[@wheeltapper1]

you do so many videos about fairy lights I was somewhat disappointed when the button cells didn't light up ;-)

[@jaycee1980]

"How can you get the soldering iron so close to your fingers?" When youve been doing it a while, you've burnt your fingers enough times that you cant feel it any more ;)

[@uN1Qu3DZ]

However you did the maths for the highest voltage on the cells which means they are fully charged, however this is a charger so they would likely start empty. With near-dead cells, say 0.9v, there would be only 6.5 volt drop across the whole thing (4.5v for cells + 2v of the red LED), so the voltage drop on resistor would be 5.5v and it would have to burn 0.1375W in that case. At least a 0805 resistor would be advisable if you're going SMD, of course the 1/4W classic thru hole resistor is still going to do just fine. In this case with 0.9v per cell the initial current will be 25mA. Only when the cells are fully charged will it trickle down to 10mA. Just something to keep in mind - even with the simplest of circuits, there are a few back-of-the-envelope calculations that you have to keep in mind when sizing a part.

[@vwegert]

red - orange - yellow - green - blue - black -- so that's a 23.456 ohm charger?

[@wilsjane]

No. Its 2,345,000.000 ohms. LOL.

[@jlucasound]

Thanks Clive!! I love rechargeables and you gave us a basic circuit to do it right. Awesome!

[@kfishy]

Speaking of leaky batteries, if I remember correctly NiMH and NiCd batteries actually don't leak (much) when they are deep discharged as they don't have much liquid inside. Alkalines however do leak like crazy and they have the characteristic fluffy stuff coming out the ends.

[@garrypkeogh]

Your tip for today Clive from the island to your left: When your heat shrink (or any "elastic" material tube in fact) is too small, insert a suitable pointed pliars into the tube and gently stretch the tube, dare I say in a sort of gynaecological fashion. This works superbly with heat shrink, delicate touch needed. For nylon compressed air line or neoprene fuel line chewing the end first softens the tube as does a mug of boiling water, tea or coffee. Stretch over the pointed pliars as before. Garry

[@alberttatlock5237]

Poundland have really cut costs to the bone with their suppliers. They use to sell garden solar lights that had 2x600mah AA batteries, the same one's were then sold with a single 600mah battery, slight design change and sold with a 150mah AAA battery, then finally with a 40mah button cell. I've opened up new ones to find a place to Fit a AA battery but no metal contacts, undid the case to find a 40mah button cell inside

[@nonchip]

for long term storage it might be actually a nice idea to have a breadboard where you just put multiple of them in and then a small circuit that (using a cheap timer switch between the socket and PSU plugpack) comes on for an hour each day and charges them to a safe level if required. then just put that thing on your shelf and they might last a rather long time

[@RichardT2112]

+bigclive I was wondering if you wouldn't mind doing a brief review of your power supply. I am not sure if you've done one in the past, but I think many of us would certainly benefit from your insight. Cheers!!!

[@ymaylove]

Awesome video! 7:00 what a wire peeler!

[@PhattyMo]

A trick I use when the heat shrink won't fit...stick some small needle nose pliers in there,and spread/stretch it a bit. It tends to relax back to it's nominal diameter fairly quickly,but usually it's long enough to get it over the joint/whatever.

[@bigclivedotcom]

I'd have done that if I'd known what was going to happen. I sometimes overdo it though and split the heatshrink.

[@restcure]

That;s the trouble with big hands ...

[@thehappylittlefoxakabenji8154]

I have that problem with condoms ! it had to be said !

[@TheMatsushitaMan]

ITS* nominal diameter, not IT'S nominal diameter. Learn the difference.

[@thehappylittlefoxakabenji8154]

John Howard I buy extra large !

[@Ducky21]

Hey Clive Could you please post a llink as to where I could buy your wire strippers? Thanks

[@bigclivedotcom]

I'm not sure the best place to get the Unior wire strippers. I think I got them from a tool store in Glasgow.

[@Ducky21]

@@bigclivedotcom Thanks Clive You have the best comment response time of anyone on KZbin

[@sparkyprojects]

If one size of shrink tubing is too small, and the next size up is way too big, get a pair of external circlip pliers and stretch it slightly (normal long nose will work, but you haven't got the reach)

[@timsjourney]

Just a hint about tight heat-shrink, try stretching it open with your needlenose pliers. You would be surprised how much it can strech, and it keeps you from using a larger size.

[@SonOfFurzehatt]

Tom Jopling I am so turned on.

[@timbdotus]

Glad someone else’s knows this trick! I can often get the higher quality stuff to stretch to 4 or 5 times the pre-shrunk size. Notice that when you do this you’re making the heatshrink a bit thinner if you’re shrinking it over something with a diameter larger than the pre-shrunk size.

[@johndrew6568]

+bigclivedotcom Thank you for showing the circuit, math and soldering it together. My nephew understood you and said, that I couldn't teach a fish to swim? I bloody have bills to pay! From now on; My nephew is your disciple. CHEERS BIGCLIVE, LOVE YOUR VIDS.

[@jonnypanteloni]

really good video clive. loved it. greetings from new zealand.

[@Seegalgalguntijak]

I've heard that NiMH cells can supposedly be resurrected when their capacity drops out by using something called a "Re-EMF Charger", which is basically a JouleThief circuit that fires the back-EMF pulses into the battery. The battery isn't even supposed to get warm with that, and after several charge and discharge cycles should become close to its original capacity. Since I have not tried this myself, I cannot say whether it works, but these pulses are supposed to somehow "reformat" the cell chemnistry back to how it was supposed to be, or something like that.

[@AdamChristensen]

Bring on the fire experiments! 10:08

[@MrBobWareham]

Yes I purchased my Molex crimping tool any years ago at £120 but it holds the wire in the perfect position and the crimp is perfect

[@v8snail]

Clive, could you not modify your capacity testing clock with 100 times the load resistor value to test at 5mA and still be easily scale-able?

[@bigclivedotcom]

Not so easy for the original, since the load was also the reed switch magnetic coil.

[@OAleathaO]

0:23 - "...also at the peak of summer...particularly in the UK." I thought the UK only had two seasons: warm winter and cold winter. LOL Just kidding...

[@JordanH859]

Aleatha Vogel just kidding? I think you're quite right! lol

[@FireballXL55]

To determine the capacity you could build a little constant current load and time the discharge. The worst bit about a soldering iron is if it is near your thumb nail and warms up the nail, it has some thermal mass and takes a while to register and when it does it takes a while to cool :)

[@jburdman7]

I hate to differ with the Clivester but to my knowledge Nickle based cells prefer to be stored at 0-40% SoC. Similar to Li-On except that Li-On are suspected to not take 0 very well, add the parasitic drain of the BMS and you may as well shoot for 40%. Just get the Nickles to 1.2xV and store them in a cold place. Which at Clive's house is over the 'heat' register ;) Lead based cells are full-charge or bust. Literally if it's cold. OK OK Here's a joke for you. What does Clive keep in his refrigerator? A: Milk. To keep it from freezing.

[@ThePhilbox]

Thank you! I recently found your channel. It's very helpful and you are a great teacher. :)

[@TheKazzarry]

Hey clive do you use a fume extractor fan when soldering? Edit: wow this comment got somewhat popular. I was simply curious if he had a ventilation fan on his little work bench, i didnt mean an industrial fume extractor.

[@evilutionltd]

Kazzarry hahaha! Funny.

[@Chuckiele]

Yes, its called nose.

[@markkeilys]

You don't need a fume extractor. Just solder in a well ventilated area. Something like an interior room with the door ajar will do fine.

[@GadgetBoy]

soldering fumes aren't dangerous

[@danp2779]

+Chuckiele Filter it through a cigarette ;)

[@dtvking]

Good old Ohms law, its triangle time lol Good video, thanks

[@Firecul]

I just use my power supply's croc clips with a pair of neodymium magnets. Works a treat if you don't mind doing them one at a time. I have 6 coin magnets so I could do 5 at once I guess but I prefer to do them individually.

[@catsupchutney]

Clive, were you using the needle nose pliers as a roach clip?

[@LoneWolfZ]

can you tell me what wire stripper you use?

[@stevenA44]

I've seen the thumbnail for this video quite a few times and this time I just decided to click on it. Interesting little charging circuit you made there. Also, I have been soldering for around 47 years (started when I was around 10 years old I think) but I wouldn't try (knowingly) to solder as close to my fingers as you do. I just about cringe everytime you do it. LOL Sometimes I think I have done it without thinking about it, when I have to get in close, but can't remember. I think the very first video of yours I watched, was the one about the ISO-Tip cordless soldering iron tear-down and adding the joule thief circuit (or something like that) Been a fan ever since. Did you come up with that circuit or was it someone else. I seem to remember you said you published it in a magazine, but you also mentioned some other gents name.

[@jp-um2fr]

I have noticed over the last 2 years that the solar panel and batteries have got smaller. AAA's were used. The LED's also appear to be less bright. Many get rain water in them and rot out so I now wrap them in cling film or mess about with good old Plumber's Mate on the encased ones. I am leaning towards running the whole lot of a DC supply and having my fruit trees like a Christmas tree.

[@quertize]

Thanks Clive. I made one but with 3 different leds and retrofitted old phone charger to top up mine solar ligths.

[@uN1Qu3DZ]

Since you started on a little bit of theory you should also give the formula for power dissipation for beginners that have not learned it yet: P=V*I or P=V^2/R, so with 2.5 volts and 220 ohms you would have 0.0284W dissipated in that resistor. Certainly negligible for a quarter watt part, in fact a tiny 0402 resistor (0.06W rating) would be able to handle that comfortably. :)

[@PV2Omni]

I've always been upset, when I get something using "older" battery technology. However, with Big Clive's teaching, I now understand why!

[@ThunderBassistJay]

Note the sequence of wire colours: red, orange, yellow, green, blue or 2, 3, 4, 5, 6. ;-)

[@jime386]

and the thumbnail made me think you had little bits of asparagus. I will never use my brain for thinking again

[@adespade119]

I find those cheap solar lights tend to get rusty in side too, I've also noticed that the switches rust so I basically soldered accross the switch contacts leaning it ON permanently. I also sprayed the pcb with oil to try to repel water, condensation. Not sure what the oil will do to the components and board long term but.. I also swapped out the crappy 600mAh batteries for some 2000mAh. And on some of the lights I snipped one of the legs of the two LEDs, so hopefully, those ones will continue to work all night, even in winter. Currently, they're nice and bright in the back garden, though I imagine as winter draws in, I might have to occaisionally charge the batteries indoors,.

[@Zadster]

If you want to guarantee a current limit, you can simply use a cheap (10p from china) LM317 + 1 resistor in constant current configuration. Might make a nice little future project :)

[@Zadster]

Not from China they aren't. Have a dig around in the usual places.

[@sayyidsahal4533]

I was informed that charging nimh cells are very complicated but they doesn't told me this simple method. I was only needed of slow charging already

[@bigclivedotcom]

For fast charging of larger capacity cells it becomes more complicated. But for trickle charging it's fairly easy.

[@fulldeepshadowmmon]

Can't believe you don't use automatic wire strippers. Life changing tool. Just realised this was 5 years ago maybe they were not so good back then

[@LightWrathme]

When working out the value of the resistor, How did you know the value of the current drawn? Is there a simple way of finding this for a circuit before it is built?

[@bigclivedotcom]

+LightWrathme Supply voltage minus all the voltage dropped across the cells gives the voltage to drop across the resistor. R= Voltage to drop divided by desired current.

[@matthewmiller6068]

curious how those hold up long-term, my only experience with those cells are in round night-light / power-failure-light things and they had a 100% failure rate with exploding batteries within a few weeks. when I looked on Amazon the reviews had a lot of similar stories.

[@bigclivedotcom]

Excellent. I really want an exploding night light.

[@matthewmiller6068]

Not sure if KZbin will let me post a link but this is the one I had a 100% failure rate within a few weeks, you can look at the review pictures and see some people took them apart. Wasn't spectacular just failed to work when it was need in a blackout. www.amazon.com/Sylvania-Re-chargeable-Power-Failure-Night/dp/B000KJZNBW

[@matthewmiller6068]

In the event KZbin blocks my link, search Amazon.com for product ID "B000KJZNBW" and it's called "Sylvania Re-chargeable LED Power Failure and Night Light" around $20 USD.

[@sziltner]

Are European solar pathway lights the only ones that use the button NiMh batteries? All the ones I have used here in the US are AA NiMh. While some post lights use 3.2V lithium polymer.

[@jamesmdeluca]

Those are Dupont pins, therefore its a Dupont crimper! Same pins used for Arduino/Raspberry Pie pins.

[@johne5854]

Interesting video. Can I ask what soldering iron you use.

[@bigclivedotcom]

Generic Chinese iron. In this case it's a Yihua 8786D with hot air pen.

[@johne5854]

@@bigclivedotcom Thanks.

[@zman1508]

This summer in sydney killed almost every one of our solar garden lights

[@bigclivedotcom]

If you think the cells are being overcharged you could tame the solar panel by covering part of it with black tape.

[@TheRasteri]

That's almost a tongue twister... "this Summer in Sydney Smoked Some of our Solar Storage Cells"

[@zman1508]

bigclivedotcom We had recorded temperature of 47C in some parts of NSW this year. Parts of the case on some of them were melted it wasn't just an overcharge situation .

[@thatsunpossible312]

Try blotting out part of the sun.

[@zman1508]

Ray Cathcart Thanks Ralph do you think you could get me Mr Burns number I'll try calling the guy he used

[@csi228]

hang on how exactly do you that the cells have fully charged and would this work on 4 cells welded in parallele? but anyways keep it up

[@haxemeback9304]

You need 2v for the led and 1.5v for charging the battery but you need to dived the charge ma into 4 so if you charging at 1000Ma you dived by 4 so each is getting 250ma and 1.5v for the ohms dived 1.5v = charging current

[@user-rs8zg8ey2b]

1.35v is a much better final voltage for nimh cells. 5 x 1.35 = 6.75v, most red led's are 1.8v, so 8.55v, minus 12v = 3.45v across the resistor. Generally you can indefinitely charge (and over charge, but I really prefer to remove them when they are slightly warm) nimh via trickel current current of 1/10C or 80mAh / 10 = 8mA. 3.45v / 0.008mA = 431 ohms. Or use a lm317 in C.C. mode.

[@BenjaminEsposti]

You could possibly put resistors in parallel with the cells. It will decrease the efficiency, but it will help keep the cells balanced. Ever taken apart and reverse engineered an ATX computer PSU? The input voltage doubler/filter capacitors (for non-apfc units; doubler mode for US voltage) have a resistor in parallel with each one. If one of them goes open circuit, the voltage across the capacitors could become unbalanced and exceed their working voltage. This typically doesn't result in a huge explosion because of the low current, but it will slowly cook the cap and it will bulge.

[@AThreeDogNight]

Hey Clive, how long have you had that whole heat gun station now, are you pleased still with it, any problems with it, parts failure & such & what is the brand name & would YOU recommend them???? Now what I wanted to say firstly but that keeps burning up my mind every time I see that heat gun is that this video is purely another GENIUS Moment. Thanks, Tom.

[@joinedupjon]

Liking the zoom facility (7:57) though it'd be even better if you had it working off a foot pedal so you could zoom in on your hands... be super good if you could activate it when you were chopping something up with the knife... and if it triggered the famous Wilhelm scream effect in such a situation that would be about perfect.

[@paulblitz]

A trick I use for holding stuff when soldering is BluTack (or the cheaper WhiteTack from £land): put a lump on the desk, and then put the connector or whatever you need to solder onto the BluTack. If you want to use a crocodile clip to hold a component, then you can put that into it too. Its cheap, simple, and lets you angle things in whatever direction you want

[@Smaxx]

True, although even cheap third hands are maybe 10-15 bucks. They give you more freedom and you can combine them with tape. :D

[@TeddB13]

In the case of NiMh (or NiCad), is it correct that putting a bunch of cells in a series like this that *may start off with differing levels of charge* doesn't matter because they will all eventually each top off due to the trickle charging? This is unlike Li-ion as you said since they are sensitive to stopping a charge when they reach their respective max voltage.

[@TeddB13]

If one wanted to set up a similar charging circuit for Li-ion, would they each need charge control/protection circuitry (e.g., DW01 chip) and you could then put each cell/chip combo into a parallel arrangement instead of series?

[@bigclivedotcom]

Each cell would require its own protection circuit. You do get series cell balancing modules. But it's often better to charge lithium cells individually or as a permanently linked parallel cluster.

[@TeddB13]

@@bigclivedotcom Thanks. Now that you say it, I do remember seeing the series balancing modules you referenced on eBay and now remember another of your videos where you mentioned how each cell needs to be monitored by the circuitry.

[@gordonw9208]

My $1 solar lights have been going strong even in winter in PNW usa. Very surprised! We had about 3 weeks of extreme overcast, and i never saw them not lighting up. Just opened one and battery voltage is 1.4, and solar panel was putting out 6mA 2.5v (its sunny right now)

[@ufos22]

I have another way to recharge lithium "pill" cells. If you have an "Energizer" style charger you can sandwich the pill battery between an AA cell and the spring connector of the recharger. Remember, negative to positive in line. I've recharged my laser gun sights with this method three times now and it isn't as good as new batteries, of course, but it works !

[@chinesefantasy]

does it matter where you put the resistor? for example could you put it before the batteries?

[@bigclivedotcom]

+Patrick Na The resistor can go anywhere in series on either side of the cell.

[@Syntax.error.]

Clive I got a question. Will you die breathing in that solder smoke and how many times did you die. But for real is there any health risk?

[@bigclivedotcom]

Generally speaking most people intuitively breath out while making each solder joint. The vapour is primarily the flux. I know lots of people who have been doing hobby electronics for their entire life and many of them are well into retirement with no health issues.

[@superdau]

As with so many things health and safety officials will tell you that they are dangerous. And yes, if it's your occupation and you're breathing them 8 hours a day, they are a health risk (in this case it could cause asthma) and it's a good thing to warn about. But as with so many things (solvents, lead, mercury, ...) there's also a completely unfounded panic around that stuff. Unless you're exposed continually there's so much other stuff in your life that's magnitudes more "life threatening" (smoking, exhausts from cars and homes in a city, mostly sitting in front of a desk, eating too much ...) you never think about.

[@jafafa]

"there's so much other stuff in your life that's magnitudes more "life threatening"" Bacon.

[@nomoredamnnamestouse]

Don't you love it when the vehement anti-vax/anti-fluoride moron types who won't bat an eyelid cooking their all natural organic food on a gas stove with the windows closed?

[@tin2001]

superdau You missed asbestos... so much panic, so little real risk. Sure it's dangerous to play in, but if you live in an asbestos fibro house, you're not going to die from it like some people think.

[@kurtrowland5587]

What prevents one cell from overcharging? Don't you typically need to connect them to a resistor network?

[@bigclivedotcom]

At low current NiMh cells can be trickle charged continuously. I'll be releasing a video with PCB files for making a USB powered NiMH/NiCd trickle charger within a week.

[@BillyNoMates1974]

would super capacitors work better in those garden lights ?

[@kathrynnoel47]

i love the sound of your heat gun ❤️

[@wilsjane]

I would check that all the cells are in a similar state of discharge prior to charging. Otherwise, the negative delta V effect on each cell would occur at different times and reduce the current to the other series cells. Immersing the cells in a weak brine solution for an hour would solve the problem.

[@Rich-on6fe]

Nicads are ok with continuous trickle charging but what I read about NiMH was that they are not - they don't have the same recombination mechanism so they dry out. I have used TC with both but can't say whether or not it actually killed the NiMH.

[@lostjohnny9000]

I keep my heatshrink in the 'fridge next to my cucumbers which are also heatshrunk.

[@cardboardboxification]

LostJohnny i like heat shrunk meat. Beef jerkey

[@RijuChatterjee]

Wouldn't the voltage across the cells get too high when they are charged?

[@bigclivedotcom]

NiMh cells can be trickle charged continuously.

[@RijuChatterjee]

@@bigclivedotcom Yeah this comment was a bit premature, sorry :P Cool video!

[@Unknown-yd5tv]

Do you have any videos on figuring out the capacity of a battery?

[@bluephreakr]

_Touch of Solder_, a new scent available from bigclive.com.

[@theantemon6720]

I got a quick question for you, if you don't mind.... I have a couple of LG 18650 cells, and a charger i bought off ebay. the LEDs on the charger turn green when the cells are fully charge. Now, I hear that laptop batteries essentially have 18650s in them also. The question is, why does the laptop indicate say 2hrs left until fully charged, whilst the 18650 charger takes at least six hours? Is there a way to make a device that will charge the cells as fast as the laptop? (maybe a certain youtuber can make a video out of it *winkwink*) Or is this a case of 'get a new, branded 18650 charger"?

[@bigclivedotcom]

You get chargers that charge with higher currents. With lithium cells it's better to get a fully built unit due to the critical voltage monitoring required during charging. Slow charging of cells is better for them than fast charging.

[@danielthechskid]

This one is easy. Laptop batteries are complex little buggers. All of the complexity allows for safer faster charging via higher charge currents. They can have (I have observed this personally): Charge status LEDs on the battery itself thermistors close coupled to the cells with silicone goop a coloumb counter chip 4 wire sensing of the pack voltage with additional wires to the mid points between each cell in series active cell voltage balancing serial communication with the computer's charging circuitry Thermal cutouts, thermal fuses, and regular fuses. Some even have a thermal fuse with a built in heater resistor that if a fault is detected the monitoring IC can power to intentionally blow the fuse and permanently disable the battery.

[@theantemon6720]

thank you so much for replying! So this taking 6hrs is overall better for the cells then, huh?

[@krgtim]

i like to charge odd sized batteries with magnets: put small magnets between batteries to hold them together and attach the crocodile clips from the power supply with magnets too. the nickel coating on the neodymium magnets is a pretty good conductor, and the pulling force is sufficient too to make a good connection, at least good enough for charging small batteries.

[@GadgetBoy]

why not use an LM317 configured for constant current?

[@talenttrading]

Constant current is brutal to a rechargeable cell. Constant voltage is the way to go.

[@GadgetBoy]

@@talenttrading Now that you say that, my brain realizes why.

[@aquinsvarghese9182]

I listened to this a couple of times, but your accent; so you're saying you DO have to disconnect NiMh batteries reach a voltage?

[@bigclivedotcom]

The NiMh cells will rise to about 1.5V and then just sit there if you keep trickle charging them. You don't need a cut-off unless you are fast charging larger cells.

[@aquinsvarghese9182]

thanks. :)

[@kenfranco7981]

Will the LED go out when the batteries are fully charged ? or will the circuit continue to draw enough current to keep it lit ?

[@michaeltempsch5282]

The same current that goes through the LED goes through the batteries. The batteries will continue to be trickle charged at about 10mA even when 'full', until you disconnect them.

[@kenfranco7981]

Thanks for the clarification.

[@Smaxx]

To expand Michael's answer, the LED is really just there to show you that the circuit is closed and there's energy flowing, since you'll connect everything in series.

[@stevesquire7878]

Clive....how would you boost the batteries from a bench supply and what voltage would you use

[@michaelparker2449]

Had to a revive a few Nimh AA batteries a few weeks back so used an 11.1v lipo to give them a jump, and I only connected for 5 seconds but the Lipo got incredibly hot.

[@DrHarryT]

As the batteries get charged the current will drop, just like you saw. When you made the final connection to start the charge you said 16Ma and then a few minutes later you said 12Ma so the current was already dropping fast. You could have just set the lab supply at the correct voltage and current limit at your desired 10MA... Me, for a power supply. I just use a 19V/2.5A laptop supply and connect to a 5A digital buck converter that is CC/CV and get a little duty service out of it. I always thought NiMh full charge voltage was the same as NiCd which is 1.34V for a full charge? You said 1.5V for the NiMh which is close to a *new* Alkaline battery which is 1.57V

[@Nugglashine]

he makes soldering look so easy

[@RexxSchneider]

The snag with using the simplest possible circuit to charge those cells is that the current will vary quite a bit if the total cell voltage is anywhere close to the available charging voltage. Using 10V (i.e. 12V less 2V for the LED) and a 220R resistor when each of the five cells are at 1.5V gives a current around (10-7.5)/0.22 = 11mA, but when the cells are at 1.2V each, the current will be (10-6)/0.22 = 18mA, which is quite a big difference. To keep the current closer to being constant, either use fewer cells in series or increase the supply voltage, both of which allow a larger resistor and hence more closely resemble a constant current charge, at the expense of poorer efficiency.

[@KubuntuYou]

Ah, so that's the secret of NiMh.

[@CoryPickerign333]

i wonder if the charge of the cells distribute from ionisation-from being exposed to the air, and the ions within the air react to the terminals of the battery..

[@OIE82]

Tip you can stretch heat shrink larger in diameter by putting it over pliers and open them slightly. Think forceps in this case.

[@xanamata5386]

if you could pull the resistor from the crocodile after leaving the crocodile clamps and before closing , then you ll have a very different something to show. an other thing , is it does not charge less than five batteries :( anyway , thank you would a ccfl to led backlight replacement be a great idea ? i want to do it and i want to get rid any useless circuits for the cclf . will it bleed ?

[@jesuschal]

Does anybody recall Clive describing the schematic of a cheap rechargeable garden LED lamp? (charging circuit shown here + the triggering and booster)? I might missed that one.

[@bigclivedotcom]

I did a very long time ago. It's all built into a four pin chip these days, with just the inductor being external.

[@crocellian2972]

This video demos the real utility of NiMH. The lipo tech comes with complexity & risk that, great for Tesla & laptops, it's not the end.