Finally got my radio, but the battery died

[Hamberthm]

Hi all! I was about to post I finally have my radio and how much I loved the looks of it.

I was listening to FM while compiling the code (awesome change, by the way), and suddenly, it quit working on me! I thought "well, the battery doesn't really last many hours then" and plugged it in and continued using it.

It turns out the battery protection circuit stopped working/giving current. With a tester I don't see any voltage coming out of the pack. If I probe right at the battery chemistry tabs beneath the Kapton tape, there are my 4 volts.

So a new battery it is, I guess... it's just mildly infuriating that I waited for a month and a half to get the thing and now I need to buy a battery as expensive as the radio itself (yes I know its cheaper on AliExpress but by no means I'm importing something again! Haha)

I'll keep you updated.

Cheers!

[EmEiBee]

protection circuit

Cheap and very easy to replace. It's cheaper and more sensible than throwing a working battery in the trash...

[Hamberthm]

Thanks for the heads up, I just searched and there seems to be one available in my market but it's too long, it measures 30mm and the one on the battery is at 18mm.

I don't feel comfortable extending the leads, they are planar and fixed pitch. I think it's possible but I don't want going thru that trouble.

[EmEiBee]

Sorry for that. That's why I save them if a battery reached her live time and go for the battery-trash. But that doesn't help you now...

[G8PTN]

Hi,
Normally the battery protection circuit will stay open circuit until there is charge flowing into the battery or the load is completely removed.
Perhaps check that with the USB-C charger plugged in, there is voltage from the charger IC (TP4056) to the battery.
I hope you manage to resolve the problem.
73, Dave

[Hamberthm]

Hello Dave! I'm afraid it's too late :(
Voltage was not present at battery leads (red and black cable soldered to the board), that means the TP4056 was not receiving any voltage at BAT pin. Sadly, I did not test if the TP4056 was charging the battery upon USB-C connection.
I removed the battery BMS module from its Kapton tape (as seen on my picture, the thin board at the battery leads) and there was voltage before this module at the root battery leads just entering the pack, but not after.
One thing I did, I removed one battery lead from the pad at the BMS board to de-energize it and reattached it hoping it would reset in case it was in any protection mode, but no luck.
So te battery is already at the bin a new one ordered...

Thank you so much anyways!

[ultimatecollections]

I had the exact same issue. The "battery" died, or rather, the protection circuit.
Is it possible to buy extra protection circuits which would fit this battery model ?
It's amazing the number of issues I hade with 3 of my mini's (one bad encoder, one bad battery and the cnc came with the battery connector disconnected!).

[Hamberthm]

Well, it's a relief knowing it happened to you too. You can get protection replacement modules, I measured the factory one to be around 15mm in lenght so something like this one (first option) should work. The key is not making a mess with the main leads wich could be dangerous, you want them as short and intact as possible.
In my country (Argentina) we have very heavy import restrictions, so I can only import so many items per year, so unless there's some seller locally it doesn't make sense for me to import the circuit. Luckily I found a replacement "603040" 800 mAh cell and it's on the way :)

[radiola2]

I think it looks like R3 has fallen off the protection board. In the picture it looks like something has been soldered there.

[Hamberthm]

Nevermind, this picture is before removing the lead! It may very well be the cause!

[Hamberthm]

Well, new battery arrived. Bad news, indeed there's a short between BAT pin and GND so the battery gets shorted upon connection. I connected the new battery and luckily this one protected itself and didn't get permanently disabled.

Am I correct by saying the TP4056 is toasted, @G8PTN ?

Thanks!

Humberto

[G8PTN]

Am I correct by saying the TP4056 is toasted,

Hi Humberto,
It seems like that could be the case.

Assuming the PCB is as per the V1 design, there are only a few connections to the BAT+ net (shown in red below).
Before removing (U5) TP4056

• Check to see if there are any visible shorts on the PCB connection points.
• Lift PIN 5 on (U5) TP4056 to see if the short clears. If it clears replace the TP4056.
• If the short remains, try removing C13.

Ideally, replace (U5) with whatever is marked on the IC, although I think the circuit was designed for a TP4056.
Before reconnecting the battery, check that the short is cleared and perhaps measure the voltage on the BAT+ with a 5V USB connected.

I hope the information helps and you are able to fix the problem.

73, Dave

[EmEiBee]

A quick tip:
Before reconnecting the battery directly, you should connect a lamp with, for example, 6V/100-300mA to the supply line in serial. If there's still a short circuit, it won't immediately cause something to smoke.

[G8PTN]

Before reconnecting the battery directly, you should connect a lamp with, for example, 6V/100-300mA to the supply line in serial. If there's still a short circuit, it won't immediately cause something to smoke.

Hi,
Yes agreed.
Initially check resistance with DMM, and use a suitable current limited power supply if possible when testing.
73, Dave

[ultimatecollections]

Very good question. I have to check that ! Envoyé à partir de Outlook pour Android<https://aka.ms/AAb9ysg>

…

________________________________ From: radiola2 ***@***.***> Sent: Friday, June 6, 2025 6:55:38 PM To: esp32-si4732/ats-mini ***@***.***> Cc: Stéphane Schmitz ***@***.***>; Comment ***@***.***> Subject: Re: [esp32-si4732/ats-mini] Finally got my radio, but the battery died (Discussion #144) I think it looks like R3 has fallen off the protection board. Doesn't it look like something has been soldered there? — Reply to this email directly, view it on GitHub<#144 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACZC7IVP6MPCRTT7XS5KUYT3CHBYVAVCNFSM6AAAAAB6VALR22VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTGMZZGI2DONY>. You are receiving this because you commented.Message ID: ***@***.***>

[Hamberthm]

Gentlemen, we have a winner:

C13!!

• Lifted pin 5 and the short was still there
• C13 did the trick

But I busted the pin 5 so I did change the TP4056 with another I had from another charging board (pain in the ass to do).

Many many thanks to @G8PTN for leading me to a quick and efficient diagnosis!

Question is if I can get C13 out of circuit safely, I don't know its purpose exactly.

Cheers
Humberto

[G8PTN]

Hi Humberto,
It’s a shame that the screen is broken, but definitely a good learning exercise. Perhaps buy a new display to salvage the radio.

As stated by Michael (EmEiBee), since the TP4056 has a feedback system, the capacitor may be required to maintain stability. It is generally best to fit the capacitor value recommended on the datasheet.

I would keep the PCB from the broken radio, you could still use it without the display and control it via the USB-C using the simple serial commands. See the information in the user manual https://esp32-si4732.github.io/ats-mini/manual.html

I believe that Max is also planning to add a CAT interface to the ats-mini firmware, which would allow full control.

73, Dave

[EmEiBee]

It is generally best to fit the capacitor value recommended on the datasheet.

This isn't necessary in most cases. The data sheets, or rather the component specifications listed there, are always designed by the manufacturer to ensure that everything will work. There's always plenty of room for improvement.

At this point, even a 100nF capacitor would easily suppress any tendency to oscillate. To absorb spikes during switching, 1µF tantalum is more than sufficient, since all the leads are very short and the charging current is supplied close to the target string, not externally.

[Hamberthm]

Thanks to both for such amazing learning! I did suspect the capacitor had these functions. I'm definitely more comfortable with a new radio, so to not worry about a stable and safe charging (I do not like the idea of lithium batteries heating up at home).

Installing a new cap is, of course, possible but very difficult for me as I not have experience with SMD, and I have to order it also. I considered soldering a full-size disc cap but had a hard time figuring out how to lay it down, so to not to press the battery cables against the case or short anything.

Yes, as soon as I remembered the encoders may fail with time, I did take the board out of the trash, and to use it via USB and WiFi control!

Humberto

[Hamberthm]

Update: Changed my mind! I put it together again, borrowed and installed a new cap from a scrap board (double pain in the ass to do), and ordered a new screen for 15 bucks :)

[EmEiBee]

Yes, as soon as I remembered the encoders may fail with time,

Most mechanical encoders don't last very long. For example, I've had to replace the encoders on my scope three times already. In other places (power supplies, function generator, etc.), I was able to convert to optical encoders because there was enough space; they last forever...

new cap from a scrap board (double pain in the ass to do

Only if you don't have the right tools for it. With a hot-air rework station or soldering tweezers, or even two soldering irons if necessary, it's pretty easy, even for me, an old fart ;)

[Ilja-code-art]

Hello all, from where Is possible to bay this radio? Ebay? AliExpress??