Sunday, 13 April 2014

how to make a 48v Transformerless Electronic Automatic Battery Pack charger for Electric Vehicles or e-scooters or e-cars or e-rickshaws

How to make a 48volt Transformerless Automatic Battery Pack Charger for electric Vehicles, e-scooty, e-car, e-rickshaws etc.

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Today I am going to explain How to make 48v Automatic battery charger circuit which is transformerless or electronic.

Now a days electric vehicals e-scooters, e-rickshaws etc.. are very popular and beneficial for regular driving. It is also beneficial because traffic now a days are increasing very sharpely and to drive in traffic consumes lot of conventional fuel and pollute the environment more, if somebody have electric vehical he or she may only need to release the accelerator to save the charge in battery. Thats why most of the people in different countries are opting for electric vehicles.

The biggest problem with these electric vehicles are their batteries are very sensitive to overcharge and take long to recharged completely. So one have to be very attentive regarding charging if their charger dont support autocut feature while full charged.

So today we are going to learn how to make a 48V Transformerless Automatic Battery charger to make you guys relieved and dont worry about charging of your electric vehicles or e-scooters.



So lets get started without wasting our time.




Todaywe are going to use very ordinary components as always to make a highly accurate over charge cutt-off feature circuit embeded in a 48v Automatic battery charger.

Circuit diagram:

48v Automatic intelligent battery pack charger for electric vehicals or e-scooters



Circuit description:

Here the main element of the above circuit diagram is its opamp IC-741 which is used here as a voltage comparator.

Here the Pin-3, which is the inverting input of the IC-741 is referenced with a fixed voltage of 4.7Volt through respective  zener and resistor network.

Here other input for charging is applied by sensing the voltage, which is actually the voltage taken from the power supply to the battery and the battery voltage itself, In other words the charging voltage which is applied to the battery for charging.

In above circuit the resistor network along with the preset or potentiometer at pin-2 of IC-741 acts as a voltage divider circuit, which we have to set initially so that the voltage at this pin of the IC stays below the voltage level at pin-3, which is the reference voltage set at 4.7v by the zener diode as in the above diagram.

We have to set the preset or potentiometer here such that the voltage at pin-2 of the IC rises above  the 4.7 mark as soon as the battery voltage charges above 50v( we taken here the 50v for battery as a threashold for completely or full charge).

As soon as the battery voltage reaches 50volt, The output of the opamp here goes low and opamp switches off the mosfet here and switch-off the charging operation to battery which is the desired condition for full charge cutt off feature.

If the voltage of the battery while charging is less than our fixed threshold which is 50v then opamp stays high enabling misfet to conduct and charging continues untill the threshold is reached.
When threshold reached the whole charging operation switched-off and our mission accomplished.

Here choosing mosfet is a treaky business because the amperage-hour (AH) rating can be different for different battery packs used in different vehicles. For example if Battery pack 16 12v batteries connected each of 200ah then then 16*200AH Here the mosfet used is
IRF3205. I recommend just use IRF3205 mosfet of safety and if infuture you want to upgrade your charger in case.



Modification:


If you want to Automate the process of charging 48v batteries means if the battery set voltage is below some extent it automatically starts charging and if overcharged then cutt-off features then the Diagram is like below


48v Automatic intelligent battery pack charger for electric vehicals or e-scooters (update)


Here the 10k ohm preset or potentiometer should be adjusted to set the full charge level while the 22k ohm preset or potentiometer for detecting the lower threshold for the battery voltage and also increase the pin-6 resistor value to 10k ohm.

Use here p channel type mosfet in second circuit diagram.

How to set up threshold for our circuit:

For setting up operation, a sample power supply should be connected across the points where the battery is connected for safety purpose, the mosfet does not require any attention initially. DO NOT connect the battery while carrying out this procedure.

Here keep the 22k ohm preset or potentiometer link disconnected initially.

Now apply the higher threshold level across the above mentioned points and adjust the 10K preset such that the RED LED just switches ON. Seal the adjusted preset with some glue.

Now reconnect the 22k preset link back into position.

Then,  reduce the sample voltage to the lower threshold value and adjust the 22k ohm preset such that the green LED just lit up, while switching OFF the RED LED. If you find no response from the circuit try using a 100K ohm preset or potentiopeter instead of the 22k ohm preset.

Now the setting is over. Every thing is done. you dont need to leave the led you can now disconnect them after setting if you dont like them.

Note that the above circuit only respond when battery is connected between them otherwise above circuit act as open circuit.

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