Help with repairing laptop battery pack - VGP-BPL9

[CatZilla]

Hello.

I found this forum via google by typing "electronics forum", so please don't bash me for being a noob =)

As the title states, I need help repairing my battery pack.
Basically, it has been deteriorating for a while now, and a few weeks ago it started to die when the indicator said there is about 65% charge left.

I took it apart, and found that one of the cells (this is a 9 cell battery) has short-circuited.
This also brutally murdered the two other cells connected to the dead one in parallel.

Now, this battery has 9 cells, each 3.7 volts and 2600 mAh.

What I tried to do, is get two cells from the two unharmed sections of the pack and put them in place of the harmed section.
This resulted in having 6 cells, connected together into 3 super-cells of two cells each, connected in parallel.
Perhaps, it will be easier if I illustrate it.
**broken link removed**

As far as I understand, this should make it a 5200 mAh 6-cell battery. However, when I insert it into the laptop, the battery is not detected. I checked the connections between the batteries thoroughly, but I can't find what's wrong.

What can I do? I've looked all over for replacement 3.7v 2600mAh batteries, but I haven't found any.

I really don't want to pay $250 for a new battery..

Thanks for the help, I really appreciate if anybody helps me at all - pointing at replacement batteries or telling me how to make the battery controller power on with 6 cells.

 

[Hero999]

I think you are lucky it didn't detected it because if it did, it might've still thought it was a 8100mAh battery and blew it up overcharging it.

Ideally you need a new battery pack.

The second best solution is to by a new set of cells.

I found some using Google
2.6Ah lithium cell - Google Search

**broken link removed**
UR18650FM Sanyo 2.6Ah 18650 3.7V Li-ion battery cell UR18650F 18650 JP products

My advice is don't buy second hand, buy new and don't but cheap Chinese cells but slightly more expensive Japanese cells.

 

[CatZilla]

Thanks for the second link, I looked everywhere to find a place where I can buy cells on an individual bases. I've seen the places where you can buy 180pcs.
I just ordered 3 cells from them.

Thanks, I'll let you know when they arrive, if the controller is back to life or not.

If not, it's like I'm buying a new battery for $300 instead of $250.

 

[Hero999]

I just ordered 3 cells from them.

Thanks, I'll let you know when they arrive, if the controller is back to life or not

If you manage to get it working, I strongly recommending another 6. There probably isn't much life left in the rest of the cells so you should really replace all of them, otherwise your new cells probably won't last for as long as you think.

 

[CatZilla]

Well, I received the batteries today, plugged them in after testing each.
Tested that every connection works, the whole battery pack is intact electrically - but the laptop does not see the battery pack. I guess I threw $50 out the window =(

 

[Diver300]

On a lot of battery packs the electronic are programmed to be vindictive. The excuse is "safety". It is actually to increase revenue.

Once the electronics has seen that the battery voltage is zero, it will store that and never work again. It's a bit like the airbag lights on a car, that once this has been flagged, there is no way out. I saw it on a £99 battery on a Mac. My daughter did what everyone does sometime with a cellphone, but with a laptop. She left it in standby, closed the lid, and we went on holiday for 2 weeks. The Mac won't shut down from standby when the battery is low. She should have just left it running, then it would have shut down itself as the battery got low. Instead, it just stayed in standby until the battery destroyed itself.

On our return, the battery didn't work. I opened it up, and all the cells were right down at 2.5 - 3 V. I charged them all separately. The battery showed 75% full on the indicator that is on it, but the computer wouldn't recognise it. I don't think that the batteries were badly damaged, but the chip in the battery pack made sure that I paid more money.

 

[Hero999]

Yes, it's a safety feature I didn't think of it before.

The reason is that recharging Li-ion cells is dangerous if they're discharged below 2.5V per cell, so as a safety feature many baterry management systems are designed to permanently disconnect the batteries when the voltage drops below 2.5V per cell.

There is probably a way to reset the electronics but it will depend on the make and model of the laptop. The protection circuit probably isn't inside the laptop anyway but inside the battery case used to hold all the cells.

 

[CatZilla]

Ah, "safety features"!
Well, I recently opened up another VAIO battery for a different laptop, and the control board was the same.
So, there must be a single reset procedure for all recent (2007-present) VAIO batteries.

Any ideas?

 

[Hero999]

You could try Googling for the board or some of the part numbers of the components.

When you reset it, you'll obviously need to do so, with the cells connected which could be dangerous if you make a mistake and short circuit something. If you connect all the cells to the board via a 220R resistor, the current will be limited to a safe level if you short anything. Then when you've reset it, you can short circuit the resistor by twisting the wires together.

If you manage to reset it, I strongly recommend replacing the remaining cells because they probably haven't got muck life left in them.

 

[mvs sarma]

New ones appear to be cheaper than $250, being at $108+ .
please see the link below
**broken link removed**

 

[Menticol]

Well, as the OP didn't posted any photos of the evil control circuit I decided to find one. The resolution is crappy, but it gives you an idea of how hard will be reseting it.

This is an opinion from an instructables guy:

"That little board you wired up the new cells to is very picky and designed to kill the battery all together in most cases of any kind of tampering because of how volatile Li-ion cells can be. When replacing the cells it can sometimes take 2 or 3 charges before it gets back to normal. But as long as the voltages are the same as the OEM one it should "work" but the computer may not be able to see the charge level and may not be able to charge it at all."

 

[mvs sarma]

those things you may have to salvage from old batteries. even if that is sold on ebay, they would have done same
see the components and get a feel whether they are faulty
perhaps it is not fault of this pcb

 

[Menticol]

those things you may have to salvage from old batteries. even if that is sold on ebay, they would have done same
see the components and get a feel whether they are faulty
perhaps it is not fault of this pcb

No, the problem is not the PCB, is just doing its job

The idea here is reseting it, look

Yes, it's a safety feature I didn't think of it before.

The reason is that recharging Li-ion cells is dangerous if they're discharged below 2.5V per cell, so as a safety feature many baterry management systems are designed to permanently disconnect the batteries when the voltage drops below 2.5V per cell.

There is probably a way to reset the electronics but it will depend on the make and model of the laptop. The protection circuit probably isn't inside the laptop anyway but inside the battery case used to hold all the cells.

 

[Hero999]

He's already spend $50 on cells so it's a good idea for him to have a go at resetting it before giving up and selling the cells on ebay (probably at a loss) and buying a new battery pack, assuming the laptop is worth the money.

 

[Menticol]

The Chinese shell the PCB's!
**broken link removed**

I googled for reseting procedures but found nothing. Is that thing microcontroller-based? (my microcontroller experience is zero). What about placing jumpers, to bypass the forced disconnection?


EDIT:
I've found some Interesting links

https://www.electronics-lab.com/articles/Li_Ion_reconstruct/index.html

Another one

https://www.summet.com/blog/2007/02/17/laptop-battery-refill/

He says: "Some charge control circuits will “shut down” if the existing cells are removed (similar to inkjet cartridges that refuse to be re-filled) so you may want to solder your new cells into a pack, connect it to your circuit in parallel with the old cells, and only then cut off the old cells. Think of this as Indian Jones sliding the statue off the pedestal while at the same time replacing it with a bag of sand"

 

[CatZilla]

Hey guys, sorry for not providing any pictures. I will take a few snaps as soon as I get my hands on a camera (should be tomorrow).
Just saying, the board is not like the one found by Menticol.

 

[knaaphix]

i dont think it could be reset because the chip has memorized the condition and it has shut down as a precautionary measure.
But there might be a way to bypass the chip.
i am also interested in knowing how to bypass the chip.

 

[Hero999]

He says: "Some charge control circuits will “shut down” if the existing cells are removed (similar to inkjet cartridges that refuse to be re-filled) so you may want to solder your new cells into a pack, connect it to your circuit in parallel with the old cells, and only then cut off the old cells. Think of this as Indian Jones sliding the statue off the pedestal while at the same time replacing it with a bag of sand"

I think it's a bit late for that.

There must be a way.

All the components are soldered to the PCB without the batteries so they must set the protection IC up then.

If he knows the part number for the protection IC, he'll probably be able to find the datasheet which will have the reset procedure.

 

[CatZilla]

I got some pictures using a lens and my girlfriend's iphone.
I hadn't had time to take out the board (and it's held inside by something resembling white hotglue). I will do so once my midterms are over (this weekend or earlier).
Pictures:
Index of /temp/sony_battery/photo

I will make sure to provide quality photos once I take the board out.

 

[Menticol]

(EDIT: I have no idea about Microcontrollers, this is just a guess, correct me if I'm wrong)

A protection IC? I don't think so, maybe is a simple microcontroller that does everything:

1) Microcontroller read's the memory
2) If memory says it's OK, the microcontoller triggers a transistor and the current starts to flow towards computer
3) If memory says VOID or OVER-DISCHARGED, the transistor is not triggered, battery keeps dead.

Jumping the transistor is not the solution, because the charging program may be also coded on the microcontroller. Charging the battery without the program and temperature monitoring may cause overheating and exploding.

What do you think?