how to build a charger for any battery

Hello guys this is another episode of the electronics for the dumbest dummies. But this episode talks about how to build laptop chargers sit back enjoy and please read cautiously.don't forget to ask your questions or leave your comments if you have any problems

        Battery chargers generally.

A battery charger could be built in different ways,

1.  Using transformer diode rectification.

2. Using switch mode .

3. Using transformerless approach.

For beginners purpose we won't be talking about the last two approaches we will only be talking on building a battery charger using transformer diode rectification.
    But firstly we will be talking about batteries generally

           Batteries

Batteries are components that provide source of energy in form of (DC) direct current, and they are also made up of electrochemical cells. They come in different voltage and current ratings.
  For clarity purpose we will only be talking about three different and common battery voltage rating types. Common batteries come in
3.7volts batteries
6volts battries
12volts batteries
             

             3.7 volt batteries

  3.7 volts batteries are the batteries use it n side our phone, power banks, PSP games,  digital cameras e.t.c. they usually come in a small PAKAGE and this types of batteries are called lithium ion batteries. They are made up of smaller batteries in them called cells and their chemical makeup is quite different.
      When they are fully charged the voltage on them tops up to about 4.2 volts. We stop charging at about 4 volts to preserve battery life.

         6 volts batteries

These are not really common battery types as to the fact that devices running voltages in the range of 6v are not really much in market. These types of batteries usually come in a different form and this battery thpe is called lead acid batteries.
  This battery contains 3cells and each cell is 2volts but once fully charged it becomes 2.3volts, therefore a fully charged 6volts battery will be giving you a output voltage of 6.9volts once fully charged. But we stop charging at 6.5volts to extend battery life

     12 volts batteries

These are very common battery types, they are mk used mostly in cars, inverters, audio amplifiers e.t.c. they come in lead acid PAKAGE also, and they have 6 cells in them in total with each cell being 2volts per cell and and each cell fully charged is 2.3volts making a total of 13.8volts for a fully charged 12volts battery. But for safety purpose we stop charging at 13.5 volts and also to extend the battery life.

        Types of battery

1. Lithium ion battery.
2. Lead acid battery.
3. Paper battery.
 NOTE: we won't be talking about paper batteries as to the fact that it is one of the latest technology on batteries and this is at beginners level.

    Lithium ion batteries

 These are batteries with a different chemical make up , and they are usually light in weight . they also have the capability to discharge their power often faster than lead acids.....they usually come in different current rating but the reason for usage in phone is light weight. Here are some pictures below.

 

   Lead acid batteries

These are battery types with a different electrochemical makeup, and usually come in two different forms

1. Dry cell
2. Wet cell

   Dry cell are usually found in inverter applications and the main reason being that they have the capability to retain their charges better than wet cell. And their acids don't dry up faster compared to wet cell which need to be charged every time to keep the cells up.

Wet cells usually find application in car batteries due to the fact that they are only used to start the car and afterwards being recharged by the cars alternator again.
  The basic advantage they have against dry cell is that their sulfuric acid are usually easy to refill other than dry cell. And their life span depend on usage, charging temperature and voltage, coupled with battery maintenance.

          Haven talked about batteries let's get on to charging any batteries.

     Building a charger for any battery.

Firstly before thinking about building a charger for a batter we need to know the exact voltage of the battery, if it fall within the range of the above commonly mentioned battery. And we also need to know the charging current in ampere hour(amps) or milli ampere hour(mah) the only difference in the two is that MAH is multiplied by 1000. The battery must be charged with a maximum of 3volts to 5volts higher than the main battery voltage. And a current of not more than 1/10th the batteries current in ampere I.e.(amp).

                               Charging circuit.

          Circuit explanation.

The first component we have there is a transformer which steps the voltage down fron 230volts to 15volts. Next is a bridge wave rectifier to convert the stepped down voltage from AC to DC I.e. a stable form of voltage useful to charge the battery next is a capacitor to filter and reduce electrical noise in the circuit and also to reduce spikes, next is an led and resistor network to indicate that power has flown into the circuit.Then next is another diode used to prevent feedback discharge from battery when there is power out. This design should be breadboarded first for prototype then later transferred to veto board or PCB circuit board.

Bridge wave rectifier diode

 They are diode with four pins and serves a basic function of converting ac to d.c and they have their different voltage and current rating. Reform to data sheet for their ratings.

Or

Materials used

1. Transformer
2. Bridge wave rectifier diode
3. Capacitor 50volts 2200uf.
4. 1k resistor
5. Led
6. Diode (1n4007)

When it come to talking about batteries there are lots more to say and they are way more complex. But for beginners purpose let's limit it to this. After building before connecting your battery please check the output voltage with a digital multimeter.

            Thank you for reading I hope this little post has upgraded your knowledge on batteries and ho to charge them. Please do this practical under a trained electrical engineer suprpervision. Any problem please contact blogger.