How To Repair Laptop Batteries
A few days ago I started repairing Laptop Batteries. And in particular the modern Smart Battery Packs. Below my first Pack opened before Repair and Reset. A BQ80201 Controller Board for the Acer Aspire 9411 AWSMi 17 inch Dual Core Laptop. Which didn’t take much time to open.
These packs can’t be fixed by just replacing the 18650 Li-ions by inserting new cells like was still possible with the old Battery Packs (Mostly NiCad and NiMH Packs). Because with the introduction of the Li-ion Battery it is controlled by an intelligent controller Board that keeps track of the Battery temperature, Over voltage when charging, Over current, and prevents Exploding or dangerous Fires . Because Li-ions are very Powerful we need this safety Controller Board as recently was big news when the Samsung Galaxy 7(? I am not familiar with all those new Smart Phones) was cancelled because it caught fire or exploded. And it had cost millions to cancel that Model out of safety concerns. And apparently Li-ion Batteries become very unstable when they get overheated.
I encountered a lot of problems that made it almost impossible for me to repair/fix a Bad Smart Battery at first. I will summarize these points of concern below:
- Smart Batteries are read and programmed by using the Philips I2C protocol. Which involves using the 3 wires SDA , SCLK, and GND. And an I2C Adapter Interface.
- When we only replace the old Batteries we will notice that when we insert the ‘repaired’ Pack back into the Laptop, it will protest that the Pack is still Bad and it will not charge correctly either. Because the old BAD Pack data is still stored in the Eeprom on the Controller Board.
- That’s why we also need to reset/reprogram the previous mentioned Eeprom too. Because the Eeprom on the Controller Board still contained for instance the old Production Date and the Cycle Count of times Charged etc.
Below another peek into the opened Acer Battery Pack (A Sanyo 3UR18650Y-2-QC236 Battery).
Reading the Pack Data and resetting/reprogramming can be easily done with the Full version of the program BE2WORKS. The free demo version only Reads Battery Pack Data. The Full version is not cheap but when we take in account that a single Replacement Battery Pack already easily costs 30 to 60 Dollar/Euro. We earn that investment back after repairing/resetting about 5 Battery Packs.
- Because every Battery Pack Connector needs another connector Cable we need to make different versions. Sadly we have to investigate the information of the Connector pins ourself. Like the 7 pins Connector I had to use for my Acer Aspire 9411ASMi Laptop Battery Pack. And my brother’s Acer Aspire 5520G Battery Pack had the same connector but only 10.8V instead of the 11.1V that my Pack had (both Packs about 4400mAh).
- I started with the BE2Works demo and therefore had bought the cheap CP2112 USB Adapter to be able to test reading the Battery Eeprom Data. Without that Adapter present the Program will quit. But before reading the Pack by I2C communication is possible we first have to find out the position of the NTC resistor on the Connector. And after I connected that pin to GND the Battery could be read by BE2WORKS. And if the Pack is still in sleep mode we also have to shortly apply an external DC voltage of about 11V onto the Plus and GND connector pins.
- Because there was no 7 pin connector Data to be found I started by checking the Plus and GND pins first. And to read out the Eeprom we don’t need to connect the Plus of our Battery Pack to our CP2112 USB Adapter to prevent damage to PC or Adapter. After that I checked with my digital Meter between all pins (except the Plus!!) to Ground if I could measure about 10Kohm that represents the temperature measuring NTC. And connected that pin permanent with GND (on the Connector). And a self made 3 wire connection Cable from the Gnd connection of the CP2112 Adapter was connected to the Battery connector. And the other two wires also from the JP2 connector on the CP2112 represent SDA and SCLK. The CP2112 will be recognized by Windows without having to install any driver.
- To prevent blowing up a one-time 4 legged Fuse on the Controller Board that is placed in the Plus Battery Pack connection on the Controller Board, we have to start removing old Batteries by starting removing the Plus wire first, than the lower next Plus, until the last Wire the GND can be removed .
And when connecting new Batteries we for the same reason start in the opposite sequence starting with the Battery GND connection on the internal Controller Board first, going up to the next higher Battery wire, until we finally end with connecting the Plus of the Whole Battery Pack, being the last wire left to connect.
(with 3 x 2 Battery Cells we have to connect 4 wires in total). The 4 legged Fuse (in my case a 12AH3 type Fuse) will get blown if the controller thinks that the Battery is tampered with. Like when the Battery Voltages are connected in the wrong sequence. The Fuse is burned by a controlled FET that heats a resistor inside the Fuse that will immediately open the Fuse. And the Battery Pack Plus is removed from the circuit in the process. All for safety reasons. 400 of these Fuses only cost about $67 and buying only five of them is also possible. Some say that to prevent this from happening we better at forehand Reset the Controller by connecting that pin to Ground. But if the Protection Flag in the Controller is already Set, the Fuse will probably blow as soon as the Cells are reconnected.
<= The 4 Legged 12AH3 One-time Fuse.
The Battery Connector specs of my 2 now repaired and reset 7 pin connector Packs are as follows:
+ + NTC SCLK SDA – – (gnd)
| | | | | | | <= (7 PIN CONNECTOR)
And as said we do not use the Plus (+) of the Battery Connector other then only for activating the Battery when it is in SLEEP mode as described under point 5.
Before we use and replace the old Li-ions 3.7V (2600mAh) Cells by new ones we have to Spotwelder them with pure Nickel strips onto their contacts. In this case 2 in parallel and that 3 times in Serie. (Parallel doubles the Packs given current). Overheating the Cells by Soldering could make them explode or shorten their life span. (I use a 709A+ Spot Welder for which I had to replace my L16A Weber Fuse automate by a C16A type because the inrush current of the 709A+ was often simply too high).
A Pack with 3 x 2 cells gives about 2 x 2200 mAh, at a voltage of 3 x 3.7 Volt = 11.1 Volt. (In case of my Pack from a Acer Aspire 9411ASMWi 17 inch Laptop).
And in case of my brothers 3 x 2 Cells Pack with another Pack controller, only 10.8V at 4400mAh (Acer Aspire 5520G).
As mentioned before we have to make another I2C Cable to connect to our CP2112 Adapter for any other Battery Pack Connector we encounter. I already ordered the 5 and 9 Pins Male Battery Plugs in case I have to repair/reset those Battery Packs in the near future too. And these are the Chips BE2WORKS can Reset/Reprogram and read: BQ208X, BQ20ZXX, M37512, BQ8030, R2J240, MAX1781, BQ80201, SN8030, BQ20869, BQ30Z55. Below my Brothers old BAD Battery Pack for his Acer Aspire 5520G that costs at least 30 to 60 Dollar/Euro new to replace the old one.
And it is good to know that BE2WORKS is able to RESET the PFF (Protection Fuse Flag). But better prevent the above mentioned trigger moments that if they occur set this 12AH3 One-Time Fuse.
As you can see it was still the old BAD Battery Data that is located in the Eeprom. (Cycle count: 223). And it already had lost about 50% of its original Capacity.
After the internal 12AH3 Fuse is blown the BE2WORKS communication with the Battery controller isn’t possible. So we first have to restore that 12A Fuse by placing a short wire over it or by placing a new Fuse. (I used a 0.1 mm thin wire. But I now know how to prevent blowing these Fuses because the Forum and the Site of BE2WORKS were unclear about this subject. And I was told to examine the Controller specs because as they said their program didn’t cover hardware questions. Which didn’t help at all. So now after reading this article any Reader can skip these questions that prevent using the BE2WORKS program the right way!)
About repairing and replacing old Smart Battery Packs and the price of the Li-ion Cells:
I previously bought 10 of them for about $25/Euro. And those 18650 Cells were all 2600 mAh Capacities (or even more up to 2800 mAh!). The pink/purple Li-ion were original Samsungs according to the Seller!
Which made a big difference quality wise because those 3.7V Cells with names as GTF (9900mAh according to the seller) or Ultrafire (9800 mAh) were a big disappointment. The GTF only gave 963 mAh Capacity, and the Ultrafire cells only 463 mAh !!! To end this article I finally will give some photos of the inside of my brother’s Battery Pack (a Sanyo AS07B31 Pack). Keep in mind that for the same Laptop there are equally useable Battery Packs from different Manufacturers with different Controller Boards but with the same Connector. In case of my Brother’s Battery Pack it took me a lot of time just to find a decent way to open it. It was heavily glued together with double-sided tape, to the Batteries and to the Case. And resetting the BQ 8030 chip took a lot more time compared to my Pack with a BQ 80201 chip. The Eeprom data had to be saved as .bin file (by clicking on the Floppy Disc icon) afterwards. These chips were not sealed, but in case they are BE2WORKS also knows more than 700 Passwords to unseal them. Below the Controller Board with the BQ 8030 DBT chip. And the next Photo shows the position of the 12AH3 4 legged Fuse. Both Photos also show the black wires with the Temperature Sensors that were glued to 2 of the Cells. As can be seen on the Photo after that. And the last Photo shows how in my old Acer Aspire Battery Pack the Wires were connected to the old bad Battery Cells. After opening and removing the Batteries and the Controller Board entirely from the Pack. So If you start by repairing and resetting your old Battery Packs you now know what NOT to do! I hope it was a useful learning experience.
I also bought this complete set of different universal Battery Pack connectors to be used in combination with BE2WORKS which also could be of interest to many readers. https://nl.aliexpress.com/item/Professional-Universal-External-notebook-Laptop-Battery-connectors-for-the-battery-charger/575654945.html
And if I not already told this before, BE2WORKS isn’t capable of reading the Controller Board without internal Batteries connected! Which is the same effect as when the 12AH3 Fuse is blown. And Before anything else ! Be extremely careful with connecting anything to the 18650 Batteries , cause in an unattended moment one of my connection wires short circuited and got up in smoke instantly!
Albert van Bemmelen, Weert , The Netherlands.
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Note: You can read his previous repair article in the below link: