Rick's b.log - entry 2023/06/06

Mom's ghost is trolling me

Trolling me.

I didn't mention this on Sunday as it was late and I wanted to eat, and I didn't mention this yesterday as I set out to mow the driveway and, well, you know how it is...

Commenting on comments

Door to door salesmen aren't really a thing in rural areas. Pikeys, on the other hand... 🤬
I don't mind the Witnesses, they're always polite, speak good English, and are amusing to troll. But I think they got the message last time when I gave up on trying to argue God's fallibility regarding Satan's existence in a universe He apparently created (because their reasoning process is twisted beyond the point of parody), and instead simply said three words:

Explain childhood leukemia.

Shame, really, as I used to enjoy openly mocking the various holy figures in The Watchtower pamphlets, like pointing out the obvious that Jesus would not have looked like Chuck Norris, but more like Yasser Arafat. After all, guys, exactly where is The Holy Land?

Finally, I won't be selling towels at a boot sale. Did it once. Mind-numbingly boring. And when you're selling stuff cheap (like some of mom's unwanted books at €0,50 each), people are still going to ask dumb questions like "will you accept 40 for it?", while offering a two euro coin...

A rechargable AA cell

Taking "rechargeable battery" literally!

This one, by the way, had failed. Zero volts output, and it just got hot trying to charge (the controller part, not the battery itself).
Which makes it a volunteer for a teardown.

Undo the film, we can see what's underneath.

How the battery is constructed.

The plastic shell can be prised off to reveal the viscera.

What's inside the insides.

Here's the socket side of the board. Not terribly interesting. I can't make out any markings on those three black blobs. So I'm going to guess just resistors. The two side by side, one reads 6.9K and seems to be sort of between the +5V and the battery +ve (72K). The other 51.5K with one side connected to the -ve. The one by where it says GND is 1K, and is 19K off a connection to -ve.
In case it wasn't obvious, these readings are in-circuit so take with a pinch of salt.

Not much to see here.

The component side, however...

Where the magic happens.

Three chips. On the left, an S8050 (marked J3Y) high current general purpose NPN transistor.
In the middle, a TL432 adjustable voltage reference.
And on the right, an AE9T N-channel power MOSFET.

I'm not going to Big Clive it and make a schematic, suffice to say what I think is going on here is the input power is shunted into the battery via the MOSFET, using the voltage reference chip to drop the voltage from the USB 5V. I think the J3Y is being used to automatically cut off the charging (and turn the red LED blue) when a certain level is reached indicating that the battery has been charged.

It's worth noting that I plugged the circuit as shown into a USB power source, and it had 1.37V between the micro USB socket shielding (connected to the battery -ve) and the spring (connected to the battery +ve).

I have a little model helicopter. The power source is a 3.7V Li-Ion cell that looks like an electrolytic capacitor. The control handset has a flying lead that can charge the cell. How does it do this? By dumping about 7.8V (from six AA cells) directly into a 3.7V Li-Ion cell with no protection whatsoever. Oh, the horror.

The helicopter is quite happy powering up using one of my drone's battery packs, but given those are quite a bit larger, it is only able to get a few millimetres off the ground (at which point it becomes unstable, tips over, thrashes around pathetically, etc).
Oddly enough, I wasn't able to find a replacement on Amazon. There were a few "super capacitors", but I'm not sure they're the same thing, and I'm certainly not going to dump seven volts into anything and "hope for the best". That's the sort of nonsense that causes these things to go "bang".

Speaking of bang, I took the Li-Ion cell from the above battery can hit it lightly with the pickaxe. It didn't blow up, or even steam. It just got somewhat flatter with a notable dent. Well, I say "dent", more like two halves barely connected. Kind of disappointing. I was hoping for an explosion that would wreck half the house and obliterate me in a way that journos around the world would say "nope, this is made up". ☺
But, alas, not so much as a whimper.

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Rob, 7th June 2023, 00:28

You only get the special effects from a damaged lithium cell if they were fully charged. Shorting them out dumps the energy quickly enough that they get hot enough to catch fire and burn. A flat battery means no energy to heat things up. And thank goodness, given the number of flattened single-use vapes I see run-over on the roads.

John, 7th June 2023, 21:30

A propos sheep: Goats, however, are often seen tethered to a fixed stake to clear land. They'll clear almost anything (remember those brambles?) and can often be hired or borrowed. They need water, and a portable shelter can be useful if left over a period remotely (borrowed from a friendly <i>agriculteur</i>, or supplied with the goat. But at your place you have an abundance of shelters, outhouses &c If DIYing, a chain tether is obligatory.    Be company for you as well, undemanding,even if bad-tempered, and costs nothing to feed whilst working continuously. No belts or moving parts to replace! one big metal post and a bucket of water, replenish daily and move stake as required.    you could raise one from a kid and satisfy any paternal instincts as well. The more I think about it the better a solution it becomes. And at the end of its lifespan, goat curry!

John, 7th June 2023, 21:33

They even eat towels! Well known for it!

David Pilling, 7th June 2023, 22:53

choppers and lion cells. Small cells which are not round, are commonly and cheaply available. Lots of different physical sizes - maybe big clive would salvage from discarded e-cigs. Place to look is Ali-Express, but want Amazon.fr - lots here, but very expensive, compared to my memory, perhaps things have changed:    https://www.amazon.fr/s?k=Rechargeable+lipo+battery&__mk _fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&crid=2ZN0V67MB4D1C&sprefi x=rechargeable+lipo+battery%2Caps%2C87&ref=nb_sb_noss    At least is this what it looks like. I have small helio, so I do know.    Guess as a kid I would search the streets for cigarette butts, now you have to do it to find e-waste. Flash cubes were a favourite to collect.    Is there any grazing animal that does not need a licence - alpacca(?) - they're all probably too close to farm animals to be left uncontrolled. Micro-donkeys. Everyone on the TV has a micro-donkey.

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