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Re: Li-ion power mod

PostPosted: Sun Nov 17, 2019 12:41 pm
by MorganFlint
Leonardolb wrote:...
Running Open DSO Shell 3.1 firmware.

And yes, I know that my device is a counterfeit one, tryied to argue with my local supplier but had no success, so I have to deal with what I have :oops:
...
Hi, Leonardolb!

Where is that firmware located?

There are two threads about alternative FW's:
viewtopic.php?f=19&t=1694
viewtopic.php?f=19&t=1953

Is the one you're using one of these, or another one?

I had the same problem with one of my units: bought a counterfeit, tried to argue (even sent the documentation provided by Jyetech) but Aliexpress only estimated a partial refund (few bucks):
viewtopic.php?f=19&t=1212#p4078

Thanks!!

Re: Li-ion power mod

PostPosted: Sun Dec 08, 2019 7:58 am
by shabr392
Leonardolb wrote:Here's my mod.

I used:
1x MT3608 DC-DC Step Up Converter Booster Power Module
1x TP 4056 Micro USB 1A Lithium Battery Charger With Protection Module
1x (7 years old) Nokia Cellphone Li-ion Battery, 3,7V 1020 mAh

I do noticed some noise, but since we don't have other simple option (which won't involve main PCB rework), I think I can live with that :lol:

20190911_101507_resized.jpg



Some questions about this setup if anyone can answer:

These cellphone/ mobile batteries typically contain a thin PCB with limiting/ thermal and/ or other protection included as shown in this picture I found on google:
Image

So in practice you have the following chain when you take into account this PCB:

[Raw LI-ion Battery] -> Nokia protection circuit -> TP4056 Micro USB 1A Lithium Battery Charger With Protection Module -> MT3608 DC-DC Step Up Converter Booster Power Module.

So that's two protective circuits in series here.

Does this impact the efficiency in any way and is it safe? I would prefer not to have to remove the PCB from inside the battery and can deal with a slightly sub-optimal setup here - but I'd like to know the pro and cons of this implementation.

The problem with all the eBay junk these days is that it is often hard to tell what batteries really have inside without partially disassembling them. Therefore it's a bit of a gamble to use the TP-4056 variant with no protection.

I did build a similar Li-ion circuit many years ago and recall an article that advised removing that internal protection PCB. I can't find the article but if I remember correctly it was to do with:
1) battery over-discharge protection kicking in too early giving the appearance of reduced capacity (or was it the over-current being triggered?);
2) additional components possibly adding noise to circuit - very relevant here.

Anyway any insight on this issue is welcomed.

Re: Li-ion power mod

PostPosted: Sun Dec 08, 2019 10:36 am
by shabr392
Leonardolb wrote:Here's my mod.

I used:
1x MT3608 DC-DC Step Up Converter Booster Power Module
1x TP 4056 Micro USB 1A Lithium Battery Charger With Protection Module
1x (7 years old) Nokia Cellphone Li-ion Battery, 3,7V 1020 mAh

I do noticed some noise, but since we don't have other simple option (which won't involve main PCB rework), I think I can live with that :lol:


I'm going to try adding 10uF tantalum capacitor on MT3608 output and shield these PCBs from the main board to see if it helps smooth out the noise.

Re: Li-ion power mod

PostPosted: Sat Feb 01, 2020 12:16 pm
by RayPooley
Wow. That's a heck of a lot of effort you folks. I would simply ask why when this works perfecty well.