The new version of the TP4056 & advices.

Thanks Barkuti. I’m actually looking into 50-100 mA range.
My cottonpickers charger starts failing and frequently stops the charge way too early.
Furthermore a few times I wished I could give sb. a 10180 charger.
And as of now I just don’t have anything around 100mA.

So…a few uses. Add magnetic leads, swap a resistor and TP4056 is ready to roll.

I was just worried that those boards may not be particularly good…
Reverse polarity protection would be nice. Myself I’m not infallable and I’d lije to be zble to give the boards to muggles. I need to look closer at that TP5000 when I’m bach home, maybe there are boards with usb ports…

a bit late but the boards should just shut off if overloaded.
if they are being killed its probably from the inductive kick from your motor.
a reverse biased diode across the 4056 board output might protect it.
note that while you measure 6a running it may pull a lot more at turn on.
protection responds and the load dump from the motor nukes the board.

My Type C TP4056 are here. :slight_smile:
Now…I know that I can adjust current by swapping a resistor.
But can I also adjust termination voltage somehow?

According to the NanJing Top Power datasheet TP4056's termination voltage is fixed. An easy method is to set one or more schottky diodes between the battery and the charger module, this will drop termination voltage by the schottky diodes' Vdrop at the given cut-off current (around 0.25V more or less).

I advice you to first measure the TP4056 module's termination voltage. Power it on without load and measure it with a voltmeter. A couple modules I have lying around measured at 4.11 - 4.12V.

I also have some on the way. Having both type-C and micro-B modules let me equip my li-ion powered stuff with dual inputs for more flexibility. :-)

Thanks Barkuti.
I unpacked and measured 2 boards, one was fluctuating 4.13-4.15V and the other 4.13-4.16V.
I hardly know anything about schottky diodes. I think I should put one in series with a battery lead, right? And it doesn’t matter whether I put it on the positive or the negative side as long as I orient it right?

Ideally I’d like to have termination at about 4V though 4.1V would be OK as well. So I need a ~0.15V drop.
I intend to tame the boards to charge at 50mA. Then the termination voltage would be 5mA.
So I need to find a diode with a Vf of 150mV at 5mA. Right?

I see that there are quite a few other parameters in datasheets. Is there anything else I should care about?

I tried to make a quick search for a suitable diode on Ali (shipping locally would kill the deal and Arrow no longer ships for free…) but the sellers don’t seem to put Vf in the title. And most listings don’t really have anything useful. Suggestions?

Just had a few minutes with my precision PSU, voltmeter and a salvaged bigass SK54 diode. At under 15mA I was seeing ≈220mV of drop, ≈197.5mV just below 5mA, ≈185mV at ≈3.4mA and ≈157mV at ≈1mA. The current fluctuation was at least at ±5% at that point.

I think the most appropiate diodes are the low voltage/high amp ones, but in practice you will either find SS12 or SS54s in AliExpress. I recently bought a super-cheap 50 piece pack of SS54 diodes, namely for this sort of duty (my testing wasn't done with one of these because of their small size, already had a hard time with the SK54 and my PSU's alligator clips). A nice bunch of them in parallel should get the job done. :-)

Thank you. :slight_smile:
Just bought a 10-pack od SS32 for 15 cents shipped, will see if it arrives. :slight_smile:

15 cents shipping included? Where is such insanely insane deal?

https://www.aliexpress.com/item/4000121587747.html

I see US$0.15 for the goods and US$0.53 for shipping to the US.

They don’t charge for shipping to Poland. :slight_smile:
And SS34 is even cheaper, 12 cents shipped. :wink:

The deal Agro posted isn't a good one for me, AliExpress Saver surcharge gets added.

However, I made another search and found this SS32 100-pack: https://www.aliexpress.com/item/32842657334.html

Which in my case is €1.11 + €0.99 = €2.10 including AliExpress Saver shipping. The actual price is $1.20, with free shipping to the US.

Guess there's no point for me to buy those now, but I wonder how much actual difference may be.

Maybe if I can scavenge some SS12 from a motherboard somewhere…

What's up?

Agro, how did it went with your TP4056 + SS32 schottky endeavour? If you already did it, of course.

I understand this may be a bit senseless but, did you measured the forward voltage of the SS32s by testing them with a multimeter? I tested 3 SS54s from the pack I bought, 0.191 - 0.193V between the leads of my Bside ZT102 (Zotek ZT102, Aneng AN8002; the diode testing current must be ≈3mA).

I myself am to modify an old Coleco Pac-Man and power it with 2x 18650 cells in parallel, using 2x TP4056 boards for charging and over discharge protection. Using my precision PSU I saw the game would run well all the way down to 2.5V and somewhat lower, and could not notice any display dimming until ≈2.75V or so. So, it's a perfect candidate for 1S li-ion conversion.

Of course I am somewhat saying the above because, to be able to make use of the boards' DW01 + 8205 management chips, I started thinking in putting a 5V SPDT relay at the OUT+ so it would switch to the voltage dropping schottky diodes when charging, and keep the MOSFET bleeding resistor path intact when not charging but :facepalm: no way. Just a reverse biased schottky diode does it, with the tiny amount of power the DW01 drains the drop will be ≈0.2V, still plenty of gate voltage (the 8205 works fine at ≈2.5V VGS and even lower).

I’m waiting for the diodes.

Guys, I have a slight problem and was hoping someone has an idea on how to fix this. When having a battery connected to the TP4056 board and the voltage falls under the over-discharge treshold the battery is cut off from the load, but as soon as it is cut off the battery rests and the voltage goes back up slightly enough to disable the over-discharge and it’s connected back to the load and then disconected again from the load. This loop goes on for quite some time and it is not a good situation at all for the load, nor the battery. Does anyone know how to fix this? Like make it not disable the over-discharge unles charging has been started or until the voltage gets to at least 3-3.1V. Thanks!

Patrikr1, even if the cell is cut-off at ≈2.4V it is a sure thing its voltage will climb back up above 3V for at least a truckload of times (the overdischarge release voltage for DW01 protection chips is 3.0±0.1V, in fact).

I once set a li-ion cell in parallel direct drive with an led, and let it discharge until the led was barely lit. It took days, and after disconnecting the cell and let it rest for a nice while its voltmeter measured no load voltage still was 2.99V.

Having said that, I do not think there's a problem with what you experience.

You may want to wait for others to chime in, though.

A 10 pack of SS32 diodes has arrived today. Yes, 15 cents shipped. :slight_smile:
But I won’t have the energy to play with them this evening, will report once I’m ready.

OK, just tested 2 diodes. 0.176 and 0.180V with Uni-T UT120B. But I fail to see what current does it use.

Agro, maybe you can try to use another multimeter in the mA range to measure the current the Uni-T UT120B uses for diode measuring.

I don’t have a DMM capable of measuring low currents, only UT210E (which shows 209 mV on both BTW).
I could solder some leads to a SMD resistor and measure voltage drop but my only resistors over 100 mOhm are 0603…
So I chained together 2 wire bundles which gave me a whooping 2 ohm.
I probably do something wrong because I almost run out of alligator clips on this setup (small clip holds wire, another holds lead, large clip holds both small clips….and so on).
Got 0.181 mV Vf and 0V voltage drop. :frowning: