Author Topic: Where to start repairing Lipo battery connector PCB?  (Read 2291 times)

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Offline TechnicalBen

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #25 on: December 10, 2017, 09:07:45 pm »
I'm not sure I can get better than the ones above (I've uploaded 3 total, first post and one a little below it).
 

Offline SMdude

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #26 on: December 10, 2017, 09:50:40 pm »
Sorry, didn't see the second lot.
That trace in the middle, scrape it back a bit from the ends and use some fine wire(piece of ribbon cable is nice).
For the 2 main traces, join with a bit of thicker wire from your collection.
Make sure the solder joints are offset a bit, so you don't get any shorts.

Nothing exciting on the end of the board that broke of, just traces out to the battery tabs.

Make sure you check for shorts.
Disconnect the cells from the board before repairing!
Insulate everything when you are done.
 

Offline cowana

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #27 on: December 10, 2017, 10:09:58 pm »
Disconnect the cells from the board before repairing!

This is the crucial part! The worst scenario with attempting a repair like this is if you accidentally short out the battery while you're scraping/soldering - keep that in mind.
 

Offline janoc

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #28 on: December 11, 2017, 01:24:40 am »

This is so simple board that it could be designed with a pencil on paper or in Fritzing (not that I recommend it). It also limits how many rookie mistakes can be made on it, especially since we are talking about making an exact duplicate of an existing design, not designing a board from scratch.

You mean you are able to home brew those exact dimension vias and God knows how many layers board are those on a pencil and paper.?   :-DD
"So simple"....???:-DD

You mean a two layer board? Seriously, what the heck are you on about? How many layers do you think are needed for that battery protection circuit? Did you actually design a PCB before?
 

Offline janoc

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #29 on: December 11, 2017, 01:31:55 am »
Lets stay on the practical side  :-+

And Janoc cut down the BS  :phew:

Sorry, so I am the one talking BS here? You have a fellow talking about multilayer boards and how impossible is it to make a replacement despite everyone being able to see the OP's photos of a simple battery protection circuit, but it is *me* to cut down on the BS?

BTW, my original suggestion was to try to reverse engineer the board (it is very simple) and see whether the OP can get a suitable replacement because these are very much generic boards. Building a new one was suggested as a possible alternative if you can't get something that would fit into the space. Repairing traces can be done, but if the board was to be epoxied together the extra thickness could be a problem in the limited space - which is why I have suggested the possibility of fabricating the board.

But I am not going to waste more time on this discussion then if it is BS.
 

Offline Bashstreet

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #30 on: December 11, 2017, 01:47:53 am »
Quote
But I am not going to waste more time on this discussion then if it is BS.

Do not forget your wheelbarrow see you in next topic.
 

Offline Armadillo

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #31 on: December 11, 2017, 02:28:36 am »
a fellow talking about multilayer boards

It may be a multilayer board in which case a repair will not be easy.

Yeah. I was fearing it was multi layer.


Problem is what is under those rf cans if the pcb is multi layer your out of luck.


That "FELLOW" was trying to apply "inflection" of the word "Simple", "so simple", maybe want us to think how "CAPABLE" he is.  Hahahahahaha LOL. But nobody give a damn  :bullshit:

Do remember to take your skeleton with you, yah!... bye.
 

Offline TechnicalBen

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #32 on: December 11, 2017, 03:47:22 am »
Sorry, didn't see the second lot.
That trace in the middle, scrape it back a bit from the ends and use some fine wire(piece of ribbon cable is nice).
For the 2 main traces, join with a bit of thicker wire from your collection.
Make sure the solder joints are offset a bit, so you don't get any shorts.

Nothing exciting on the end of the board that broke of, just traces out to the battery tabs.

Make sure you check for shorts.
Disconnect the cells from the board before repairing!
Insulate everything when you are done.

Ok, So I should desolder the batteries first? Is a heat gun and something to insulate the battery from the hot air best, or just a large (large thermal capacity) soldiering iron best?
 

Offline Armadillo

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #33 on: December 11, 2017, 04:12:34 am »
The "T" pad is connected to R3 at the bottom. There is a similar 2 vias pad the other side.
Looks like its not implemented or use. I suppose this could be the thermistor pad.

 

Offline SMdude

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #34 on: December 11, 2017, 07:33:49 am »
Sorry, didn't see the second lot.
That trace in the middle, scrape it back a bit from the ends and use some fine wire(piece of ribbon cable is nice).
For the 2 main traces, join with a bit of thicker wire from your collection.
Make sure the solder joints are offset a bit, so you don't get any shorts.

Nothing exciting on the end of the board that broke of, just traces out to the battery tabs.

Make sure you check for shorts.
Disconnect the cells from the board before repairing!
Insulate everything when you are done.

Ok, So I should desolder the batteries first? Is a heat gun and something to insulate the battery from the hot air best, or just a large (large thermal capacity) soldiering iron best?
Just use a soldering iron. Add fresh solder while you do it. It should not take more than a coupe of seconds per tab. Use some small pliers to take the heat out of the tab once it has been removed.
The key is to do it fast so the heat(or much quantity of heat) doesn't have time to transfer into the cell.
 

Offline Armadillo

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #35 on: December 11, 2017, 11:19:27 am »
Maybe consider again. Alot of thermal mass.
Tape up all other pole and tracks and work each track at a time would be easier, is it so?
 

Offline SMdude

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #36 on: December 11, 2017, 12:25:58 pm »
Nicely spotted!

Yes, if it is spot weleded to the pad then forget about removing the cell. This is live open heart surgery!

All in all, as long as you are careful you won't have any problems. Do the small trace first.
 

Offline TechnicalBen

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #37 on: December 11, 2017, 10:33:19 pm »
Ok. I'll keep thermal load in mind, and be as quick and delicate as I can.
[Quick Edit]
I said this was a learning experience. So, it's given me some time to practice checking continuity on traces... The middle track seems to go from B2+ to B1-

I'm assuming for now, the bottom track is the one that goes from B2- to the charge control/balancing? I'll check that trace next.  :-/O

I've put soldering up the wires on hold, as I thought I had some solid core, but turns out it's stranded. Expensive stuff here in the stores, so I'll get some ordered in.
« Last Edit: December 11, 2017, 11:17:25 pm by TechnicalBen »
 

Offline Armadillo

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #38 on: December 11, 2017, 11:16:16 pm »
Ok. I'll keep thermal load in mind, and be as quick and delicate as I can.
[Quick Edit]
I said this was a learning experience. So, it's given me some time to practice checking continuity on traces... The middle track seems to go from B2+ to B1-

I'm assuming for now, the bottom track is the one that goes from B2- to the charge control/balancing? I'll check that trace next.  :-/O

No, No, No. Spot weld you will not be able to desolder it. If you see on the right side tab, someone had already tried to pry it.
SMdude, please better clarify with OP. thanks.

Edit: They soldered metal segment taps onto the pcb and after do spot welding onto it for a purpose, to avoid damaging the battery by the heat.
« Last Edit: December 11, 2017, 11:24:00 pm by Armadillo »
 

Offline TechnicalBen

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #39 on: December 11, 2017, 11:35:36 pm »
Sorry, I know I won't, as it's "welded", I meant on the other traces, I'll be quick and delicate, trying to protect the cells.  :-+

No one has tried to pry it. That was bent during removal of the battery or during unfolding (the pcb is folded into the cells and in on themselves).

As said, a simple "oh, PCB on one side, cells with wires on the other", as I've seen in other tabs (dead so sacrificial attempts! :D ), was shown to obviously be an old design. Same with phones, I never really offer to repair those, as the good old days of screws are simple repairs are gone to glue and extremely dense boards (see the iPhone X for amazing tech, but a nightmare for repair).

I only do part swapping for PCs. Soldering for hobby stuff. But as this has been explained to not be too taxing, I'll give it a go. Some pencil wire and .4mm wire on order for the next couple of days, at 1/4 the price the local Maplin would have charged without delivery on top. :)
« Last Edit: December 11, 2017, 11:39:20 pm by TechnicalBen »
 

Offline SMdude

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #40 on: December 11, 2017, 11:44:11 pm »
You can be a bit more generous with heat on the traces. Just scrape off a section of solder mask(the green stuff) with your favorite small flat screwdriver, tin it with solder, then put a wire on it. Job done.

Either that or just upload it to me, I'll fix it, then you can download it again!! :P  :-DD

Practice on a pcb that is more dead/unwanted than this one so you can get some confidence. It really isn't that hard.
 

Offline TechnicalBen

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #41 on: December 11, 2017, 11:49:44 pm »
Scraping done. Checked some continuity... and I'm puzzled.  :-//
No idea how it is "wired" up. Other than bridging the traces and hoping for the best. I cannot see where/how there could be any shorts. I could always file off the one tiny bit of copper on the surface near the snap. But it mainly snapped where there is only a trace on one side.
 

Offline Bashstreet

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #42 on: December 11, 2017, 11:58:34 pm »
Scraping done. Checked some continuity... and I'm puzzled.  :-//
No idea how it is "wired" up. Other than bridging the traces and hoping for the best. I cannot see where/how there could be any shorts. I could always file off the one tiny bit of copper on the surface near the snap. But it mainly snapped where there is only a trace on one side.

The issue is if you while soldering on during testing how your wire fits you touch between traces (negative to positive) and short the battery.
You can limit the possibility by using non conductive heat resistant tape while soldering or test fitting.
« Last Edit: December 12, 2017, 12:14:41 am by Bashstreet »
 

Offline TechnicalBen

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Re: Where to start repairing Lipo battery connector PCB?
« Reply #43 on: December 28, 2017, 01:18:29 am »
A little update. Bridging the traces has allowed the battery (so both cells) to show to the bios/tablet and enable it's charging/voltage checks. I'll upload pictures of my *atrocious* soldering. But as a proof of the repair option, it's good! (Providing the cells have survived etc)

I know of the risk, so am keeping an eye on it, and if I do decide to replace the screen, will probably just run it as something to telnet into remotely. Though using just the board + power would be good, but I'm not sure the thing will boot without a battery connected. :(
 


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