3.part- Fail of the week - 6600 mAh genuine HP laptop battery teardown

Hungarian version.

To have more 18650 cells, I thought to buy a used laptop battery and get the cells out. It turned out it was not a good idea. However it seemed to be a good offer. For 7 USD a used HP 12 cell laptop battery. I thought that it is not a recent model, but I have not expected this. It arrived with the post, it is a very massive and heavy piece.

It contains Sony cells, great!

Between the picture above and below after more than an hour suffering I was able to open it. It was built from almost a 1mm thick plastic and glued or melted together very well. I even had to use a chisel to open it. This was inside, I like the cell color.

There was no indication about the manufacture date on the outside, however there are signs inside. 2002 or 2003. Oh, no. It may be 13 years old?

The manufacturer put two thermistors into the battery, very clever. One is in the intersection of the left four cells, the other is on the lower four cell. It is better than in the other ones I opened, where only one thermistor was glued to one cell.

I have numbered the cells, so I will know which was where.

Controlling circuit:

The usual heat fuse and two chips which are anonimized.

But here we go! Let's measure the voltage. The three on the right had 2,27V, the other three packs had 1,73V... So I will not be able to use them for security reasons. If the voltage of a li-ion cell falls below 2,5V the inner chemistry gets damaged. The identification codes on the cells tell that they were manufactured in 2003. They are 13 years old! How can this be still around? And who would pay anything for this? I do. But you can't win them all, this buy was a failure. I cut off the two thermistors, so I have now 4 of them. I will take these cells to the recycling center where they already should be for 10 years. I do not wish to open such batteries, it was so hard and I won nothing, but experience.

Battery capacity measurement with an Arduino - In other words, let's discharge the batteries

Hungarian version.

Welcome everyone. Who has read my plan - that I will use the Keweisi capacity meter to measure my 18650 cell capacities - knows that I have chosen the Arduino solution, because it gives a more accurate reading. I have spent several days to find out what parts I need and what code do I have to run. I have analyzed several similar projects on the internet. I had to create a simple yet effective code. With my solution it is possible to measure the capacity of 1,2V Ni-MH, Ni-Cd and 3,7V Li-ion or polimer batteries. In fact you can measure the capacity of any battery with this design which has a voltage lower then 5V.

Ingredients:

-a microcontroller, in this case I used an Arduino Duemilanove. Of course it is not a genuine Italian one, it is an aftermarket model from China. I do not think this is still in production, the Uno model is the recent one, but not much has changed on it since. If someone has another type of microcontroller, my connection diagram will not help.

-a resistor. This should be rated at least 5W, so it will be able to bear the load. I have bought a 3,9 OHM and an 5,9 OHM ceramic resistor. The smaller OHM rating we use, the bigger the current will be to discharge the batteries. Why does it have to be 5W rated? It is because if for example the Voltage is 4V and I want to discharge with 1A current then the output is: 4V*1A=4W, this energy is turned into heat on the resistor. If we use OHM's law for calculation at 4V and with 3,9 OHM resistor, the Current will be 4V/3,9OHM=around 1A. Of course as the battery voltage decreases over time, the current will become smaller and smaller. If I use the 5,9 OHM resistor, then at 4V the current will be: 4V/5,9OHM=0,677A. I used the 4V example because a fully charged Li-ion cell gives around 4 volts. This was just an example. But if for instance I want to discharge an AAA 1,2V Ni-Mh battery, the numbers are the following, with a 3,9OHM resistor it will discharge it with 0,307A, which they can bear. I am not sure how much current they can give, but I think 0,3A is enough to prevent overheating. It seems they can bear 1A discharge current as well. You can now calculate the required resistor size if you know with how much current you want to discharge the battery.

-a MOSFET. I used one with three leads called: IRLU8256. This is required to open and close the discharge circuit controlled digitally with the Arduino. It is like a switch, but you can control it from the Arduino code. In case of a Li-ion battery you can turn the discharge off, to prevent over discharging.

Important characteristics: Vds=25V, so it can bear the voltage. Rds=around 5mOHM, here the smaller is better so it has a little resistance. Vgs should be little, so the Arduino 5V power is able to turn the FET on and off.

-a battery to be discharged. You can also buy battery holders, but used magnets to hold the wires on the battery. This is a cheaper solution.

That is all. I have read on the internet, that other designs also measure the voltage on the MOSFET and if there is any loss they use it as well for the current calculation. My MOSFET always gave 0V here, so I left it out.

The two other designs I used as inspiration: One, two.

Warning! The resistor heat up during discharge so it can burn your hand. Of course it will not burn, but it will be hot. Always use wires which can bear the load that you are using. It can happen that the MOSFET stays open and keeps discharging the batteries if we shut the Arduino off or if we stop the code run in the middle. Do not leave it unattended and make sure that it will not over discharge the batteries. I take no responsibilities for the damage this discharger may cause.

If there is no battery connected and the code runs, it will give false Voltage readings.

You can see on the pictures how to connect the wires. Although there are two batteries connected in series on the picture, this is only because there was no other picture in the program. I usually discharge one cell at a time.

Arduino code:

#define MIN_VOLTAGE      950   // mV, the voltage should not drop until this amount. At a Li-ionnál: 3000, with NI-MH:950

int FETPin = 13;      // select the digital output pin for the LED and the FET
int BatVoltage = 0;
int STOPI = 0;
float loadCurrent, TotalCurrent, TotalCurrent2, onescurrent;
int sec = 1;

void setup() {
  unsigned long PrevTime;
  Serial.begin(9600);// start serial port to send data during run to the PC
  pinMode(FETPin, OUTPUT);
  digitalWrite(FETPin, LOW); 
  Serial.println("6");	//countdown until the discharge process, I use this time to connect the battery
  delay(1000); 
  Serial.println("5");
  delay(1000); 
  Serial.println("4");
  delay(1000); 
  Serial.println("3");
  delay(1000); 
  Serial.println("2");
  delay(1000); 
  Serial.println("1");
  delay(1000); 
  
  Serial.println("START!");
  int val1 = analogRead(0); // we take an initial test to measure the initial voltage
  BatVoltage = map(val1, 0,1023,0,5000);;
  Serial.print("Starting voltage in mV=");
  Serial.println(BatVoltage + 40); // here I added 40 to the the measured voltage as the Arduino measuread an incorrect Voltage
}

void loop() {
  
  
  if(STOPI != 1){
    
    digitalWrite(FETPin, HIGH);  //here we active the the discharge circuit
    int val1 = analogRead(0); 
    BatVoltage = map(val1, 0,1023,0,5000);;
    
    loadCurrent = (BatVoltage + 40) / 3.9;              //at the end of the equation the exact resistor rating in OHM should be changed

    onescurrent =  loadCurrent / 3.6;		//here we calculate the Current amount load in a second
    TotalCurrent = onescurrent + TotalCurrent;
        
    Serial.print(BatVoltage + 40);   
    Serial.print(" mV   I=");
    Serial.print(loadCurrent);		//Current load amount per second
    Serial.print(" mA   Time=");
    Serial.print(sec);
    Serial.print(" s   Totalcurrent=");
    Serial.print(TotalCurrent / 1000);   // total mAh burnt
    Serial.println(" mAh");
    sec = sec + 1;
    if(BatVoltage + 40 <= MIN_VOLTAGE){
      STOPI = 1;
      Serial.println("Voltage is lower then the set min Voltage STOP!");
    }
  }
  else{
    digitalWrite(FETPin, LOW);  
  }
  delay(1000);  // wait one second, then get next set of samples  
}

The measured capacity is just an estimate, as the higher the discharge Current, the lower the measured capacity will be.

2.part- 7800mAh genuine IBM Laptop battery teardown - Lenovo T60

Hungarian version.

Welcome everyone. This battery was made at the time when IBM has already sold its laptop business to Lenovo, but the IBM brand was still printed on these products. It is from August, 2006, so it is almost 10 years old. I red this from the battery markings. The battery was used in a T60 laptop. Its teardown was a bit harder than the noname battery I have already written about, because the case is stuck together better.

So the brand is IBM, it is 10,8V and has a capacity of 7,8Ah. As it has 9 cells, it can be calculated that each cell has 2600mAh capacity in it. The cells are Panasonic made and their specification says they have 2550mAh capacity each. If we take it nine times, we get only 7,65Ah capacity, which is slightly smaller than the indicated number on the case.

It looks like this when I have ripped it open. It is interesting how the third row is split a bit. I think this is only a design solution, it has no real purpose. 3 cells in series and 3 in parallel. There is the controlling circuit on the top and there is the heat sensor duck taped to one of the cells. That's all. Well, I have not expected anything else. 6 of the cells had 3,65V voltage, 3 of them had only 2,65V. The guy, from whom I get the cells, told me, that after a charging the battery would not work anymore. We will see if the cells are still in working condition or not.

In the noname battery I previously opened had a nicer controlling circuit. That had a red circuit board and was not covered with such rubber material.

The microcontroller chip is an M37512 together with a 61048FP. If you are interested their specifications you can search on Google. The heat fuse can also be found on the board, it looks slightly different like on the noname circuit.

The temperature sensor can measure only the top right cell's temperature. Maybe it is put there on purpose? Maybe that cell is the mostly used.

This is what is left from the battery, I will use the temperature sensor for other projects.

Here is the capacity list of the cells:

1370
1317
1192
1362
1264
1062
1001
1187
1031

mAh.

How to find out if the cells are in a good shape. For each cell:

1. Measure voltage, if it's less than 2.5v, do not use it.
2. If it gets hot during charging, do not use it.
3. After charging the voltage should be between 4.1v and 4.2v.
4. After 30 munutes if it's fallen less than 4v, do not use it. Note the measured voltage.
5. After 3 days, measure the voltage again, if voltage has fallen more than 0.1v from the recorded voltage, do not use it.

1.part- Found aftermarket 4400mAh Laptop battery teardown - Lenovo G450

Hungarian version.

I am planning to build an electric bicycle Li-ion Battery pack. More people on the internet are using 18650 Li-ion battery cells found in Laptop batteries for this purpose. 18650 is a size standard, these are 3,7V cells with significant capacity. I have recently found a laptop battery in a dustbin and I though from the size of the battery that it contains 18650 cells. I have taken it home. It happens regularly that only 1 or 2 cells are faulty in the pack, but the others are still functional. Or just the control circuit shuts it down for some reason. In these cases the battery will not let to charge itself. This is the time when they get in the dustbin. But there are still some usable cells inside which can be used. Of course their capacity does not reach the manufacture capacity, but for hobby and project purposes they are still ideal. They can be also used in a flashlight, storing energy to recharge USB devices and so on. So let’s see.

As it does not have any brand it is a noname aftermarket piece. It is written on the outer shell that it contains Li-Ion cells and it has a capacity of 4400mAh and it gives 11,1V. The sticker on the side tells that it was manufactured in the middle of 2013. It has not been used for too long. Maybe it is because the cells are bad quality or the full battery capacity has decreased to a level that it was unable to give enough power to a laptop, or it would have run only for some minutes.

The case was easy to open at the joints. This process requires attention, not to damage the cells or to cause short circuit, as the cells may get overheated or set on fire. There are six cells in this battery.
They seems to be robust compared to an AAA or AA battery, they are bigger and heavier. Three are connected in series and three are connected with them in parallel. 3,7V*3=11,1V as it can be seen on the sticker. From the 4400mAh capacity indicated it is obvious that each cell is rated 2200mAh. The controlling circuit is located on the top right side. There is a temperature sensor duck taped to one of the cells.

It is simple plastic case. What is surprising is that if we take a closer look at this inner side, the initial numbers and markings can be seen from the mould which they used in the factory to manufacture this shape of plastic.

I have cut the cables connected to the controller circuit, then the strip which connected the cells together. We have to take care again, not to cause a short circuit. With the help of long nose pliers the metal strip can be torn off the cells. I used a circular motion to wind it down as I would open a tin can.

The other side of the case. The cells were glued in with hot glue.

The cells seem to be noname, nothing can be found out from their printings. I have searched with Google to SZN cells, a 2200mAh piece cost 3,6 USD in Hungary. The better quality branded ones costs around 5,3 USD each. I was wondering here about the laptop battery prices. A noname similar laptop battery costs in Hungary around 36 USD. A branded one costs around 72-108 USD. But what costs this much on the batteries? One cell costs 3,6USD. 6*3,6=21,6 USD. Plus the package and the controlling circuit. These cannot cost around 14,3USD, because in China they manufacture in huge quantities and in bulk it is way cheaper. So on each of the noname batteries, there is a profit around 10,8-14,4 USD. But I think it is much more. Now let's see the branded ones. Those cost 2-3 times the noname's price. But the branded cells are not cost this much more. Not even the controlling circuit. If we count 6USD*6=36USD if we count the best quality cell. Plus the controller. On the branded batteries there has to be more than 70USD profit on each. This is amazing.

Let's see if the cells are still in working condition or not. They say if a Li-ion cell's voltage drops below 2.5V then it is damaged unrecoverable. I have measured the voltage of these cells and all was on 4,1V! This is normal since while charging they are charged until 4,2V when they are full. So it is possible that all the cells are still functional.

The controlling circuit was made with modularity in mind. It can be seen on the left that this connector part can be changed depending on what type of laptop will it serve. So the other part of the circuit can be always the same. Of course the programming details are changing like how many cells are there, the capacity, the charging current and so on. The temperature sensor is checking if there is an overheating happening. But I think the temperature should be checked on all cells, because what if the one on the left gets too hot, until the sensor on the right senses it, it may be too late. Maybe the branded batteries have different design. The controlling chip is an Atmel MEGA406. You can find its specifications on the internet. There is one more interesting thing on the circuit. The small white cigarette shape with the white putty, it is a thermal fuse. If they reach the melting temperature they cut the circuit. Because it is intact this was not the cause of the dumping.

I have found something interesting on the internet. There is a chance to "reset" the controlling chip, so it will delete the stored information about the charging cycles and errors. It is possible that after resetting the battery would still work for some time. There is a manual about this here. In short it describes that if we search on the internet for the specifications of the controller chip, there is usually a reset leg on it, which in the mentioned case has to be connected with the battery ground wire. This would reset the chip. Please experiment on your own responsibility! Unfortunately I cannot try this on my battery, as I do not have a laptop to test it with.

To be frank I thought the batteries are more complicated inside, but they are not. They are also very expensive compared to what is inside them. I will keep the temperature sensor for future Arduino projects.

I have measured the cells capacity:

1- 659mAh
2- 51mAh
3- 1238mAh
4- 1303mAh
5- 780mAh
6- 875mAh

When they were new theoretically they had 2200mAh capacity. It is interesting that it has decreased in this magnitude in 2,5 years. We do not know it is because the battery was used too much, or the cells are bad quality cells. But the 51mAh cell proves that it had to perform very badly. I do not think it was capable to run a laptop in this state.

How to find out if the cells are in a good shape. For each cell:

1. Measure voltage, if it's less than 2.5v, do not use it.
2. If it gets hot during charging, do not use it.
3. After charging the voltage should be between 4.1v and 4.2v.
4. After 30 munutes if it's fallen less than 4v, do not use it. Note the measured voltage.
5. After 3 days, measure the voltage again, if voltage has fallen more than 0.1v from the recorded voltage, do not use it.

Soshine E3 - Teardown and test - 18650 battery charger and Power bank

Hungarian version.

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Update 2016.03.05: the Chinese seller agreed in a part refund and paid me back 4 USD to my PayPal account, however PayPal has billed me 0,5 USD for something. For the money I received? This is ridiculous. The seller offered a change if I send the charger back, but the posting fee would have been more expensive than the product itself. The seller was very helpful.
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I have ordered from Ebay, China, a 18650 battery charger which is also a Power bank. Its "brand" is Soshine, type E3. I have chosen this as it is cheap, cost 17 USD with shipping to Hungary. It can charge up to 4 batteries and it charges them individually. A power bank means that if there are charged batteries in it, it can charge devices through an USB cable. So for instance if we are walking in the forest and there is no mains power to charge our phones, then this can be used after we charged the batteries inside it. The 18650 batteries are not included they have to be bought separately. I will use 18650s from laptop batteries.

It looks great, feels great and it also works, however there is a slight problem with it. One of the slots is overcharging the batteries over 4,2V. 4,2V should be the maximum. Strangely it charges in the next slot till 4,2V next to it till 4,19V next to it till 4,18V. So be careful with it particularly with overcharge protected 18650s. I have complained to the seller because of this, let's see if I will some refund or not. So if I do not use the first slot for charging, this works well.

Oh and one more small thing. This thing consumes 1,4mA all the time, which get raised to 3-8mA in every 3-4 seconds. This means that it drains 62mAh daily from the batteries inside it. I think this drain is shared between the installed batteries. My assumption is that this drain is used by the microcontroller and it fluctuates because it gets out from a power saving state to check the cells in every 3-4 seconds. So be careful with this, if you just leave the batteries in it, they will get drained as the days pass. My solution for this is use a piece of plastic to cut the contact between the batteries and the E3, so it cannot drain them.

How it works. You put in the batteries, it does not matter how many and into which slot. If you connect it to a power source it will charge them, if it is not connected it simply shows the charge levels of the batteries. If you connect a device to be charged to it onto one of the usb slots, then it shows the voltage and mA drained from the batteries. When it charges or it is used, then the LCD backlight is on, this consumes 20mA, but can be turned off if you press the back button for 1 second then releases it.

Is it worth to buy? Unfortunately because of the overcharging I am not so happy, if I get a refund then I may get used to not use that slot. Of course no manual or specification is attached to the power bank. I do not know how this goes in China, but it is funny. If you accept the negative things, it can be used well.

On Ebay they are also selling it under name TOMO V8-4 .

Teardown:

We can see the date and revision of the PCB on the lower right side: 20150615-V2.6. The previous version does not show the voltage and the current when it charge other devices. They have also changed some electric parts as well. Here is the previous version. Some people complain because of the overcharging and the drain from the cells which I mentioned. On the picture above can be seen the 4 charging controller chip and the 4 diodes for the reverse polarity protection. Below you can see the microcontroller which is a PIC16F1933 . This controls everything, including the LCD, it has a temperature sensor inside as well. Of course the cells temperature is not checked on this board.

Have fun!