Can I savely recycle the PCB of an old power bank?


Askarus

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I need a little help with some electronics.

Question - short version:
Will it work if I disassemble an old power bank and use the PCB to add new cells and build a custom power bank?
The cells will have the same voltage but probably come in different numbers and have different Ah values compared to the original cells.

Background:
I have 2 of these: ()
It is not available for purchase any more.
It is the only power bank I know of that allows 15v USB-C output (powers Nintendo Switch dock) and so many DC output current voltages (5V / 9V / 12V / 15V / 16V / 19V / 19,5V / 20V / 24V).

Unfortunately one of these is broken now. It discharges rapidly and looses current over time. The other does not.

Question - long version:
I suppose the fault is the battery cells and not the PCB (why should the PCB break)?
Also I suppose all the output logic is within the PCB.
The battery has 4 (or 5) cells.
As the PCB is all I need, may I safely remove the old li-ion cells and add new ones.
Given the new cells have the same voltage as the original ones and are linked in parallel of course.
(For now the answer is yes I suppose. That much I figured)

Other Question:
May I add more cells to the PCB?
Example:
The old power bank has cells 5, each 5v and 1000mAh.
May I remove them and add add 7 new cells, each 5v, 1200mAh?
Given the new battery pack has a high enough C-rate.

I suppose that will work, too.
All tutorials I see are about using cheap 5v 2A PCBs, but none is about recycling a power bank PCB.
From what I know of electronics it should be save to add new li-ion packs.
However I want to make sure I don't burn my house.
So if one could give me a quick YES or NO, it would help me a lot.
 
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Phlyra

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Not sure how much it will help this particular question but have you ever tried by Micah Toll?
 

levi

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Without inspecting the PCB it's hard to say precisely, but I'd expect it to be using voltages to set it's limits and therefore as long as what you take off is 5V and what you put in is 5V that'll be fine (although I'd expect li-ion cells to be 3.6V actually). I'm not sure what C-rate is. Charge rate or something to do with capacitance? It's possible it does everything using timers in which case provided you have more capacity that the old batteries it won't fail, although you should never be able to charge them fully.

And I wouldn't dismiss the PCBs themselves being broken. If it's capable to pumping out 24V at north of 2A that's quite a punch and could easily have burned up small traces or fried resistors. I can't immediately think of a fault like that that would present the way you say though, which screams duff cells to me.
 

Askarus

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Without inspecting the PCB it's hard to say precisely, but I'd expect it to be using voltages to set it's limits and therefore as long as what you take off is 5V and what you put in is 5V that'll be fine (although I'd expect li-ion cells to be 3.6V actually). I'm not sure what C-rate is. Charge rate or something to do with capacitance? It's possible it does everything using timers in which case provided you have more capacity that the old batteries it won't fail, although you should never be able to charge them fully.

And I wouldn't dismiss the PCBs themselves being broken. If it's capable to pumping out 24V at north of 2A that's quite a punch and could easily have burned up small traces or fried resistors. I can't immediately think of a fault like that that would present the way you say though, which screams duff cells to me.

5v was just an example.
The actual PCB has 3,7v and probably 5 cells of 10000mAh cells.

C-rate: https://www.drone-zone.de/battery-g...ating_How_much_current_can_the_battery_supply
It is how much current a battery can output.
Battery has 1Ah and C1 -> can output 1A
2Ah and C2 -> max output = 4A
That's how I got it.

There is also a C-charge value which determines how much Ampare can go in at once.

I did not output 24V. The max was 15v via USB and maybe 19 via DC.
I'll wait the reply of the manufacturer. If I don't get any replacement, I'll open it up and check the PCB.
The cells are glued to the housing. I don't want to rip them off in case I have to send it back.

Not sure how much it will help this particular question but have you ever tried by Micah Toll?
I'll have a look. Thanks.
I always wanted to build my own power bank.

EDIT:
The book does not contain information about PCB and voltage converter.
I mostly know about how to chain batteries.
What I don't know about is the PCB and if I can reuse an old power bank PCB.

Does anyone know a high quality power bank pcb with at least 3 exit ports?
One being DC with adjustable voltages and an other one providing USB-C 15V?
 
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kuru

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Somehow I expect more batteries to fit in there. You need like six 18650 for a true 20000mah bank. Apart from that that measurement is bollocks anyway. You want a proper capacity rating in watt hours. https://techtest.org/mah-und-wh-angabe-bei-powerbanks-37v-oder-5v/
And those are Chinese mAh on top of that. I'd open the thing up, find the charging chip and look at its datasheet. Looks like this case would come apart rather easily compared to its plastic brethren.
 

Askarus

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Somehow I expect more batteries to fit in there. You need like six 18650 for a true 20000mah bank. Apart from that that measurement is bollocks anyway. You want a proper capacity rating in watt hours. https://techtest.org/mah-und-wh-angabe-bei-powerbanks-37v-oder-5v/
And those are Chinese mAh on top of that. I'd open the thing up, find the charging chip and look at its datasheet. Looks like this case would come apart rather easily compared to its plastic brethren.
It's 185Wh.
I do not want to use 18650 cells.
They need too much room.
I'd rather go with these if I want high quality or those if I want to be cheaper.

As I said, I already tried to open it, but the cells are glued to the case.
I want to wait for the reply of the manufacturer.
If I don't get a replacement I'll tear it apart.
Well, maybe I should not wait and just do it, as it's more fun ;)
 

Phlyra

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5v was just an example.
The actual PCB has 3,7v and probably 5 cells of 10000mAh cells.

C-rate: https://www.drone-zone.de/battery-g...ating_How_much_current_can_the_battery_supply
It is how much current a battery can output.
Battery has 1Ah and C1 -> can output 1A
2Ah and C2 -> max output = 4A
That's how I got it.

There is also a C-charge value which determines how much Ampare can go in at once.

I did not output 24V. The max was 15v via USB and maybe 19 via DC.
I'll wait the reply of the manufacturer. If I don't get any replacement, I'll open it up and check the PCB.
The cells are glued to the housing. I don't want to rip them off in case I have to send it back.


I'll have a look. Thanks.
I always wanted to build my own power bank.

EDIT:
The book does not contain information about PCB and voltage converter.
I mostly know about how to chain batteries.
What I don't know about is the PCB and if I can reuse an old power bank PCB.

Does anyone know a high quality power bank pcb with at least 3 exit ports?
One being DC with adjustable voltages and an other one providing USB-C 15V?
Fair enough. I would recommend asking in the Endless Sphere forum; they have some serious battery experts there (like Micah Toll) and a lot of them build their own batteries.

Sorry, by PCB I was thinking of the BMC, rather than a separate one exposing USB interfaces etc.
 

Askarus

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Can it be that not using the battery for about a year "confuses" the electronics?
They behave strange now.
The other one also went from full to low within under an hour.
And the other one charged from empty to full within an hour, even if it usually takes 5+hours to fully charge.

I left them at full charge for about a year without using them.
Might that be the cause?
I'll use them now for a while and see ow they behave. Maybe they "recover" by themself after going through a couple of charge/discharge cycles.
 

levi

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Yes, I've seen battery electronics get confused about the state of charge rather than the battery chemistry having gone duff quite a few times now. Just try to run it low then charge it full a couple of times and it should recover.
 

Phlyra

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You’re supposed to keep batteries at a storage charge level (50% charged or something like that?) for long term storage, not only to reduce the likelihood of puffing/thermal runaway but also to improve the lifespan of the battery generally. I also read something about cycling them every three - six months?
 

Askarus

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You’re supposed to keep batteries at a storage charge level (50% charged or something like that?) for long term storage, not only to reduce the likelihood of puffing/thermal runaway but also to improve the lifespan of the battery generally. I also read something about cycling them every three - six months?

I know. I did not plan to not use them for that long.
It's not that easy to "quickly" charge/discharge such a hige power bank.
They were meant to be "always available" when I need them.

I'm still used to Pandora batteries.
They are the gold standard for me.
Even the almost 10 year old batteries I used every day for years are still without any noticeable flaws.
My laptop battery (from a 3000€ gaming laptop) died dafter 3 years (completely).

Yes, I've seen battery electronics get confused about the state of charge rather than the battery chemistry having gone duff quite a few times now. Just try to run it low then charge it full a couple of times and it should recover.
Interesting. That's new to me.
Time for some recharges.
Will take a few days for sure as I have no reliable way to quickly discharge the batteries.
Need to use them for all my gaming then.
 

spud42

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yes you can reuse the boards from powerbanks. most probably they use a 1S 4P or more to get the higher capacity.
a few caveats..
you have to use cells of the same capacity i.e. you cant use a 2500mAh cell and a 1000mAh cell in parallel.
do not solder the batteries . the heat can damage them and damaged cells can burst into flames.
IMG_1482.JPG

this is a 3S10P 12V pack im making for camping, well there will be 3 of them each 12V 26AH

edit:
C rating is per cell in my case they are samsung 2600 mAh cells recovered from Dell laptop batteries. so if i parallel 10 2.6Ah cells the pack will be able to output up to 26Ah assuming 1C . BTW forget the hype on ebay from the chinese battery sellers there are NO 18650 cells that are more than 3500mAh .

you need to check what voltage inputs the powerbank PCB takes. it may have DC to DC converters for the higher voltages to boost from the 3.7V nominal of a cell . but it may also take a higher voltage and convert up and down .....
 
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Binky

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How does the existing system detect battery temperature?

It's worth checking that you get that set up correctly with the new cells, otherwise it will either keep cutting out, or you'll have no protection against "interesting" failure modes.
 

Askarus

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Thanks for the input. It will surely be valuable in the future for me.
At least one power bank seems to have recovered.
Had no time to once more discharge the other one.
Really seems like the electronics had some quirks and not the cells.
That's very good.
The one which has recovered lasted for about 5 hours gaming without surprises. Seems like it's back to normal :)
 
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