Ultra small solar power bank with retro circuitry (with schematic)

I missed a resistor on the first page of the schematic while drawing a neater one. Can you work out where it goes? The answer is at the bottom of this description.
This is a small keychain solar power bank I bought from eBay. What I didn't know is that it was NOS (New Old Stock) dating back about ten years, and it shows what an amazing leap the circuitry in power banks has made. Instead of a single chip, inductor and smattering of capacitors, this unit has lots of discrete circuitry to give a similar result, but still cheats on the end of charge detection.
The unpopulated chip position does correlate to being an LTH7 charge control chip, but has no facility to turn off the LED on charge completion. The existing DW01 LED control hack would not work, since the LTH7 would terminate the charge just before the DW01 turned off the MOSFET (and disabled the LED).
It's actually quite an interesting design.
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/ bigclive
#ElectronicsCreators
Did you manage to work it out? There should have been a 10K resistor between the base of the LED transistor at the left hand side of the schematic, and the collector of the one that switches its base to the 0V rail. The link shown would have shunted the current intended for the LED to the zero volt rail.

[@AluVixapede]

I like how my tiny brain read "retro power-bank" and immediately jumped to "NiCad????"

[@amorphuc]

Wow. That's wild! Nice job working all of that out. I think of my dad going from the tube era to transistors and ICs where he'd work backward from a desired result and make it happen by drawing up a schematic and getting out the soldering iron. He was a calibration engineer for Stewart Warner many years ago and would always come home with fun stuff to play with. I wish I knew even a percent of what was in his noggin.

[@miked4377]

yeah i bet he knew a ton!

[@wtmayhew]

If this power bank is like one I have, the solar panel is handy for discharging. A little bit of light activates the circuit, but isn’t enough to charge the cell. Meanwhile, the LED indicator slowly drains the cell. 😊

[@sihamhamda47]

Yeah the solar panel at that size itself can only draws 0.05 to 0.1 watts even at full exposure to sunlight. Not enough to charge the phone battery to reasonable capacity even when it's leaving at full sunny day However that small sized solar panel is enough to charge very small devices which has small battery capacity, such as calculators and small rechargeable flashlights

[@smellyghost]

I always like seeing random cheap things like this that are seemingly over engineered for what they are. But it makes a lot more sense knowing that it's an old module since ones these days are so cost effectively designed (for better or worse depending on the module).

[@gvii]

The nice thing about having a 3D printer is you can be quite destructive with something like that and whip up a new case with in a relatively short bit of time. It's also rather nice for that occasional incident when you really didn't intend to be destructive, but you were anyway. I might have a smidge of experience in that... Just a smidge.... Really....

[@zyeborm]

You mean ad hoc educational opportunities? I'm great at those!

[@johnpossum556]

This whole circuit, in a nutshell, could be said to be "I am not a Transistor but I play one on KZbin" 💙💛

[@chrisjames3087]

Great job, Clive. You should do an infrared thermometer.

[@demef758]

11:30 Switchers are funny things. In this boost circuit, the two types of capacitors (tantalum and ceramic) are there to attenuate the two main components of output ripple voltage. Tantalums give you fairly high capacitance in a small package volume but at the expense of large equivalent series resistance (ESR). Ceramics have virtually zero ESR. When these two capacitors are paralleled, the two types of ESR are in parallel with one another, the total ESR in the output filter capacitor is almost zero. The output current waveform of a boost is usually a trapezoidal looking thing. That current waveform times the total ESR is a voltage (I*R) and is one component of the ripple voltage, which is made almost zero due to the presence of the ceramic caps. The other component of ripple voltage is due to the boost current going into a capacitor. You know, V(t) = int(I*dt) /C. To keep this term small, you need a large C. This explains the presence of the tantalum cap: to reduce this term (1/C). Thus, you use a relatively cheap big-value tantalum in parallel with a cheap lower-value ceramic to lower the output ripple voltage on the boosted 5V output! Boost circuits are notorious for the amount of ripple voltage they produce, as well as the stress levels the output filter caps have to endure, particularly for high output current boosts.

[@ZaneDaMagicPufferDragon]

Nice little battery pack for charging my Bluetooth headphones and other small Micro USB Accessories!!!

[@TheeShaggySniper]

I had one of these over a decade ago... back then, it could charge your phone, they didn't need as much power back then like they do now... Loved that thing. Best $20 I ever spent. It got me onto Solar powerbanks, which nothing ever really stood up to that little bugger. That little thing took maybe a couple hours in daylight to charge up - but when you don't scale proportionally, you run into issues. I've got a 15,000mAH battery with an 8" solar panel... that thing takes WEEKS to get 25% charged.

[@TimPerfetto]

Love hearing your thought process as always; thank you

[@hughtube4me]

Seeing you with your IPA dispensing bottle reminds me of my younger days when we used similar bottles to top up the Honeywell paper disc chart recorders that recorded our production data ! AH the good old analogue days

[@dragonrider4253]

What an interesting little circuit. It may be a _little_ over complicated, but it seems like it'd work quite well for an emergency power supply.

[@stephencelliers9127]

Once again another detailed breakdown. Great way to learn electronics and troubleshooting. 🎉

[@TopEndSpoonie]

Thanks Clive, that was well explained. Well done.

[@Aco747lyte]

I deduced that a 10K resistor was missing in the left-hand side of the schematic. And you did very well, Clive. Great analysis, as always. And as often as I can, after my shift ends (like an hour ago) I come and watch your vids with great interest. Many thanks for this! 😊❤

[@xxbambamxx7261]

Idk whyi find you're videos fascinating 😅 But they are, so keep them coming 👌

[@SkigBiggler]

Interesting to see how what once was quite a circuit has been shrunk into basically a single chip. Makes it obvious why VLSI was such a game changer in cost and processing power.

[@thingys-rd7id]

To open this sort of case I use a knife placed on the seam then tap the knife with a small hammer, the seam usually opens with little damage to the plastic so the item can be put together again. Appreciate the hard work you put into your videos always enjoy them.

[@KeritechElectronics]

Interesting and nicely reverse-engineered :)

[@stevejagger8602]

Long live analogue electronics - it is a dying art - hence the sharing of a former work colleague's attitude to the overuse of microprocessors in a comment to a previous video. Thank you once again for your comprehensive analysis.

[@RS-ls7mm]

Actually where I worked analog was the most stable department. Always need power supplies and interfaces to strange devices. If anything died it was the old discrete logic design.

[@simonhopkins3867]

They put lots of work into it. Now it seems like you have as well. Thanks buddy.

[@gregorythomas333]

Interesting...haven't seen this kind of design for quite a while :)

[@twocvbloke]

From 2013, it really is "vintage" when it comes to portable battery technology... :P

[@spacejihadist4246]

I have one just like that hanging on my key chain. I've never charged it. I did use it once to charge my phone when I run out of fuel in the wilderness. My brother gave it to me this Christmas and I am really thankful.

[@Graham_Rule]

I always like seeing you 'reverse engineering' circuits and try to work out how things worked and what the original designer had in mind. Have you ever had anyone mark your homework by telling you that they were the original designer and how well you'd done?

[@bigclivedotcom]

Yes. Some of the original designers have told me they enjoyed my reverse engineering. Strangely, none of the designers of the bad stuff got in touch.

[@wisher21uk]

Looks like a handy bit of kit thanks for the insight and explanation 😊

[@ElvenSpellmaker]

Another one for the Big Clive dictionary: Vice of Knowledge

[@S7EVE_P]

I bought one of these for a project for a tiny wireless camera, but in the end the output wasn't quite enough (I ended up using a solar wall light with the led's disconnected), but the circuitry was impressive for such a small and seemingly cheap appearance - there is so much in it and it has potential to be a solar keying torch with a few mods :-)

[@kolmaxik]

My major is “optical engineering”. We’ve had four semesters of so called “electrical engineering”. This video is a very good example of me understanding every single word but struggling to understand the whole concept. I admire your fluency in reverse engineering different circuit boards.

[@kolmaxik]

I was a bad student:

[@bigclivedotcom]

You may find it a lot easier to learn naturally at your own pace instead of the usual out of context data cramming that happens in educational establishments.

[@user-hq2fy5cs1k]

*I love everything you do*

[@papaalphaoscar5537]

I grew up with those kinds of circuits. Then came op amp comparators and 555's. Now everything is done in software using microcontroller boards. Recently I made a power on delay circuit for a compressor using an ATtiny module, a packaged Hi-Link power supply, and a relay module. It could easily have been done using a dropper cap, rectifiers, a Zener, a triac, a relay and a handful of passives. But who wants to mess with soldering on a perfboard or etching a PCB? 😁

[@davelowets]

Yep, the analog days are pretty much gone... I fought the whole microcontroller phenomenon to the bitter end, but I finally had to cave-in and learn it, or I would have been left in the dust and confused when it came to modern electronics.

[@papaalphaoscar5537]

@@davelowets Actually it is much easier. More like Lego, but you will have to learn how to write code.

[@mrfoodarama]

Happy Birthday Clive, Hope you're having a great day 🎂🎁

[@petersage5157]

It's great to see the Vise of Knowledge again.

[@petehiggins33]

Almost as good as the knowledge of vice.

[@petersage5157]

@@petehiggins33 Of course my favorite Big Clive tool is the X-ray Device; I keep hoping Clive will find an excuse to use the Deluxe version that AvE sent him.

[@andy70d35]

Clive, well done working that out.

[@brianmaldonado3723]

I am old school and that was godamn awesome!

[@wherami]

neat! old but still useful for some things. always good to have backups

[@LoneWolf0648]

ive seen a LOT of devices where they have a tiny solar panel to keep the battery topped up rather than as a way to charge it. that kind of makes sense with a device like this since you would only use this once in a while but you want it to stay fill even while your not using it. a good example is that hand crank emergency radio/flashlight/battery bank combo thing off amazon that has a million clones, the best selling one lists its solar panel for that reason.

[@Mike_5]

Brilliant Sherlock Holmes job here Clive - the finer details really do matter

[@notahotshot]

Manufactured in 2013, "Old-fashioned". 😂 Way to make a fellow feel old.

[@bigclivedotcom]

Old fashioned for that type of product. Not for humans.

[@wdavem]

I actually like this thing. Great video also!!

[@marvintpandroid2213]

"oooh, just look at the circuitry on that" Big Clive 2023

[@marvintpandroid2213]

@@Okurka. True but published to us plebs today.

[@pault6533]

Nice little unit. Because the case is white and the solar panel is on the other side of the unit from the lithium cell, one can be confident about sitting the unit in direct sunlight without any issues other than yellowing of the plastic or increased brittleness.

[@shepshep8654]

I get a weird inception vibe looking at the PCB. Your camera circuits are filming battery circuits transmitted through a bunch more circuits, resistors, and diodes to my phone you get the point. Your eyes to my eyes with a bunch of electrons in between.

[@BloopTube]

Id honestly have one of these in the shed window or hanging off my camping rucksack trickle charging my headlamp quite happily

[@keithking1985]

Very impressed, busy little board. I like.👍🇮🇪💚😁 I really enjoyed that video, but Lord God Clive I'm wide awake now. But worth it.

[@carlubambi5541]

Great as always !

[@Unfinished80]

I love my Cliveypoo videos!

[@markiangooley]

Clive had to RELEASE THE CRACKIN’

[@gabotron94]

Have one of these somewhere with an ipod dock connector, from around 2007. No charge input, in addition to the tiny battery, so you could charge like 20% of your battery VERY slowly every few days. Never got it to work repeatably.

[@Menjari]

Clive, we should take a bunch of your notebooks and donate them to schools. A few can be mounted and framed. Like how you did your resistor art. Spread knowledge!

[@silver1fangs]

I love watching... I have no clue on half this stuff though. I have a power bank board that had a little spark and just quit working after a wire touched somewhere it obviously shouldn't. It's truly not worth fixing I feel but I also am not sure what to look for as far as assessing damage... it's just perma-off

[@paulbeard3238]

So you are saying I know half well you know a lot more than me so well done 👍😁🙂👍👌

[@sarathai2876]

I like the part with the three capacitors something and think about

[@brianallen9810]

"The Vice of Knowledge"🤔 I really like this, think I'll try and find it on E-Bay.

[@dcallan812]

Well I dont know how I managed to miss this on Parton, just as well I have your dingleberry pressed 🔔☺ Funny I tll dont have a power bank of any kind, I really should get ne in the current power issues we might have ib the UK. My electric has been capped for a while sadly no longer the electric people sent a letter warning me my bill on average use was going to be just over £5000 a year. 😱🤦‍♂ interesting item 2x👍

[@lindonwatson5402]

well done old chap

[@johnjones4825]

4:00 Not having a vice at hand, I once or twice replaced frayed power cords on my colleague's laptop chargers. I propped the chargers against a small concrete step and gave them a short, sharp glancing blow with a 4 pound hammer. You takes your chances and sometimes you wins. Other times you waits for the company to (eventually) send a new charger...

[@siypic]

"Look at the circuitry on that" .......classic line never used in any Carry on film.

[@venenareligioest410]

If you had that on your key ring with your Aspod you’d be ready for anything Clive 👍

[@chrishartley1210]

I like it. The modern minimalist 3 component design is all very well but it removes the possibility to modify the circuit for another purpose. What do they call those little bottles, I've seen you use them for solvent and flux, they look very useful.

[@bigclivedotcom]

Generic metal tip dropper bottles from eBay.

[@fredflintstone1]

hmm, I love it old things that work really well at the job they were intended to do, I wish I did 🙂

[@d.t.4523]

Good luck.👍

[@wtmayhew]

It makes me feel old when a device from 2013 is considered dinosaur technology!

[@plainedgedsaw1694]

I think they power the chip from after the diode to protect it from reverse polarity.

[@Mike-H_UK]

Great. I will buy two of these, so when one is flat I can recharge it with the other one.

[@micheals1992]

The best place to put a solar panel is on a keychain in your pocket 😜

[@mforrest85]

I thought you was about to get out the x-ray for that one at first.

[@miked4377]

nice little circutry.....ip booster..nice..

[@Miata822]

You say "retro" but I'm waiting for the charge bank circuitry with tubes (valves).

[@davelowets]

You gonna haul it behind you in a trailer, with your car? 🤔 🍻

[@_BangDroid_]

I love the old always-on powerbanks. Rare as hensteeth now. Great for arduino or IoT devices that use low current. Funny, if you want always-on now, you have to pay a premium, whereas 10 years ago it was very common.

[@davelowets]

It's not hard to trick the newer ones into being always on..

[@_BangDroid_]

@@davelowets I know, it's just tanks efficiency

[@davelowets]

@@_BangDroid_ Yes, on alot of them it does. Especially the ones that have the battery level LEDs on all the time when it's running. Occasionally I still run across a new one that has the older type of circuit in it, that doesn't use much current at all when you mod it to stay on if nothing is plugged into it.

[@NinoJoel]

I have seen one of these around 2010 with a full size usb port

[@johnsenchak1428]

The first page is-mostly like diode steering * using the unction of the transistors turn on or off the LED

[@kewlztertc5386]

This is just like the mini games in Spiderman.

[@FCWW87]

CLIVE!! I’m newer to the channel, couple months, and I’ve stumbled upon the Manx Beard Club. Hoping to see some more!?

[@bigclivedotcom]

You'll find the MBC on the BigCliveLive channel now.

[@FCWW87]

@@bigclivedotcom Thanks Big Clive! That’s probably a good move, and I will go over there and add a sub:). Can’t wait to see you get your plaque!

[@joruss]

Said boost chip looks like a RT9266PE , FB reference point is at 1.25V by the datasheet, resistors pair used here (487k/150k) make it exactly 5.31V you've got on tester.

[@4dirt2racer0]

that really is impressive, especially since u were holdin it up to a lamp, not even the sun lol :p

[@levitemple5982]

Hey Clive, As a newbie electronics enthusiast, I always feel as though it takes me an unreasonably long time to reverse engineer. Roughly how long did this take you?

[@Broken_Yugo]

Practice makes perfect, gets easier when you start memorizing some of the common little circuits that make up the full schematic.

[@davelowets]

It'll get easier as you start to recognize all the little common circuits that are piled into one large one, such as snubber networks, switch de-bouncers, decoupling caps, pull-up resistors, R/C constants, and so on. It took me a LONG time at first also, never fear, you'll get there. 👍

[@davelowets]

@@Broken_Yugo Oops, I didnt even read your comment before I posted mine... Great minds think alike, I guess... 🍻

[@bigclivedotcom]

This one took longer than normal due to the odd circuitry.

[@Eduardo_Espinoza]

I screamed when you said how cute it was!!!! :DDDDD then i screamed again because of how complex it was!LOL ^꒳^💧

[@EpicATrain]

I'm surprised you didn't bust out your explosion containment pie dish.

[@paulbeard3238]

It's usually on the top left of his bench in arms length well it usually comes from that area 🤔

[@uggima1]

Yup charge ic pinout matches ltc4054 (or its clones)

[@phonotical]

For the battery type and the circuit board, it says to me, copied from an old phone without really knowing how to eliminate parts ... That diode has my postcode...

[@EugeneShamshurin]

it could have been a leftover from Solio chargers. Solio also used solid-encased cell, similar components, but way better solar panel and case.

[@jmr]

I have some solar keychain lights. I've always wondered if they actually charge the battery or if they shoved a coin cell in and the panel is for show. Glued shut so I haven't taken them apart. Eventually one will fail and I'll find out.

[@bigclivedotcom]

Some are fake. Standard non rechargeable cell and no wires to the panel.

[@jmr]

@@bigclivedotcom I suspected that. No point destroying one till it stops working though. I'm not as good at putting together as I am taking apart. With my infrequent use a coin cell could last about as long as a rechargeable battery. Definitely beyond the return period.

[@zyeborm]

​@@jmr some are even better and connect the solar panel to a non rechargeable battery 😂 They don't like that much

[@davelowets]

I actually got a REAL one at my local hardware store for $1. It had a REAL solar panel, with REAL circuitry, hooked up to a REAL rechargeable 2032 cell. I guess I should consider myself lucky

[@jmr]

@@davelowets That's interesting. Rechargeable 2032 cost more then $1 all by themselves.

[@theelmonk]

Do yiou get enough voltage from the solar cell to re-enable the dw01 or does it need USB to get started ?

[@bigclivedotcom]

If expect the solar to be able to do it in bright enough light.

[@skepticfucker280]

I actually want one......

[@samholdsworth420]

Smol I could use this for my USB headphones. Since I have two pairs these days and no 3.5 mm Jack. The power bank I'm currently using is giant compared to that.

[@samholdsworth420]

Those "disposable" banks should be outlawed...

[@harrowtiger]

The Nice of Voledge, 1st cousin of the Cink Palculator?

[@piconano]

I was wondering what happened to the vise of knowledge! I feared the worst, and thought it died in a horrible accident!

[@BensWorkshop]

That is quite interesting. Presumably you could recase with a bigger battery and a bigger solar cell. Got a link?

[@bigclivedotcom]

It came from eBay in the UK. Definitely someone selling old stock.

[@derwqdwfpx3701]

4:19 use the cutters to cut into the piece were both halfs join, it'll pop off.

[@phonotical]

Solar panel is connected? Mmm, I can't wait 18 months for that to charge!

[@curtishoffmann6956]

Can I use a solar bank to make time deposits?

[@maxrichards9980]

I enjoy your videos and I was wondering if you have [or could] use discarded lithium cells from vapes, to make up a battery bank of cells [and maybe a step up to 5v], which could be used as a portable power bank for a phone?

[@bigclivedotcom]

Yes it is possible to use a parallel cluster for that. I have a video where I used two in a USB rechargeable module.

[@maxrichards9980]

@@bigclivedotcom thanks for the speedy response, I'll see if I can find it. Thanks again.

[@bikkiikun]

Interesting, I wonder why they would use a 2k resistor, instead of the 1k on the DW01 datasheet?

[@davelowets]

They had extra 2k's....

[@ruben_balea]

A decade ago many dumb phones came with 300mA chargers and it seems 550mA chargers are still common today.

[@CanizaM]

2013 design... almost 10 years ago!

[@MsLancer99]

Then where the days. We use to do this way now we do it that way

[@pointedspider]

I have a zillion little metal can transistors from the 60s

[@AUATUWVSH]

1.177394 volts on that sense divider... i was expecting ether .6v like you said or 2.5v

[@ssupertutorial]

Hey , it looks cool, where did you buy it ?

[@bigclivedotcom]

eBay.