auto turn off battery charger advantages and disadvantages
#1

Auto turn off battery charger disadvantage& advantage
Reply
#2
Have you ever tried to design a battery charger which charges the battery automatically when battery voltage is below the specified voltage? This article explains you how to design an automatic battery charger.

Below charger automatically shut off the charging process when battery attains full charge. This prevents the deep charge of the battery. If the battery voltage is below the 12V, then circuit automatically charges the battery.

Automatic 12v Battery Charger Circuit Diagram

Circuit Diagram of Automatic Battery Charger
Circuit Diagram of Automatic Battery Charger
This automatic battery charger circuit is mainly involves two sections – power supply section and load comparison section.

The main supply voltage 230V, 50Hz is connected to the primary winding of the center tapped transformer to step down the voltage to 15-0-15V.

The output of the transformer is connected to the Diodes D1, D2. Here diodes D1, D2 are used to convert low AC voltage to pulsating DC voltage. This process is also called as rectification. The pulsating DC voltage is applied to the 470uF capacitor to remove the AC ripples.

Thus the output of the capacitor unregulated Dc voltage. This unregulated DC voltage is now applied to the LM317 variable voltage regulator to provide regulated DC voltage.

The output voltage of this voltage regulator is variable from 1.2V to 37V and the maximum output current from this IC is 1.5A. The output voltage of this voltage regulator is varied by varying the pot 10k which is connected to the adjust pin of LM317.

[Also Read: How To Make an Adjustable Timer ]

Lm317 voltage regulator output is applied to the battery through the diode D5 and resistor R5. Here diode D5 is used to avoid the discharge of battery when main supply fails.

When battery charges fully, the zener diode D6 which connected in reverse bias conducts. Now base of BD139 NPN transistor gets the current through the zener so that the total current is grounded.

In this circuit green LED is used for indicating the charge of the battery. Resistor R3 is used to protect the green LED from high voltages.

Output Video:


Circuit Principle

If the battery voltage is below 12V, then the current from LM317 IC flows through the resistor R5 and diode D5 to the battery. At this time zener diode D6 will not conduct because battery takes all the current for charging.

When the battery voltage rises to 13.5V, the current flow to the battery stops and zener diode gets the sufficient breakdown voltage and it allows the current through it.

Now the base of the transistor gets the sufficient current to turn on so that the output current from LM317 voltage regulator is grounded through the transistor Q1. As a result Red LED indicates the full of charge.

Charger settings

The output voltage of the battery charger should be less than 1.5 times of the battery and the current of the charger should be 10% of the battery current. Battery charger should have over voltage protection, short circuit protection and reversed polarity protection.

NOTE: Also get an idea about how to build a battery charging level indicator circuit?

2.Automatic Battery Charger

Circuit Diagram

Battery Charger

Battery Charger

An Automatic Battery Charger Circuit for sealed lead acid batteries is mentioned in this project. It is a pulsed-charger type circuit which helps in increasing the life of batteries. The working of this circuit is explained below.

LM317 acts as voltage regulator and current controlling device. The 15V Zener diode is used to set the LM317 to supply 16.2V at output in the absence of load. When the 2N4401 is turned ON by the output of 555, the ADJ pin of the LM317 is grounded and its output voltage is 1.3V.

LM358 acts as a comparator and voltage follower. LM336 is used to supply a reference voltage of 2.5V to non-inverting terminal (Pin 3) of LM358. A voltage divider network is used to supply a portion of battery’s voltage to inverting terminal (Pin 2) of LM358.

When the charge in the battery reaches 14.5V, the input to inverting terminal of LM358 is slightly greater than 2.5V at Pin 3 set by LM336. This will make the output of 555 go high.

As a result Red LED glows and the transistor is turned on. This will ground the ADJ pin of LM317 and its output falls to 1.3V.

Battery charger using 555

When the charge in the battery falls below 13.8V, the output of LM358 is high and the output of 555 is low. As a result, voltage flows from LM317 to battery and Green LED glows to indicate charging.

[Related Post– Lead Acid Battery Charger using LM317]

3.Battery charger Using SCR

Battery Charger Circuit

Battery charger circuit

An automatic battery charger circuit using SCR is implemented in this project. It can be used to charge 12V batteries. Batteries with different potentials like 6V and 9V can also be charged by choosing appropriate components. The working of the circuit is as follows.

The AC supply is converted to 15V DC with the help of transformer and bridge rectifier and the Green LED is turned on. The DC output is a pulsating DC as there is no filter after the rectifier.

This is important as SCR stops conducting only when the supply voltage is 0 or disconnected from supply and it is possible only with pulsating DC.

Initially, SCR1 starts conducting as it receives a Gate voltage via R2 and D5. When SCR1 is conducting, 15V DC will flow through the battery and the battery starts to charge. When the charge on the battery is almost full, it opposes the flow of current and the current starts to flow via R5.

This is filtered with C1 and when the potential reaches 6.8V, Zener ZD1 starts conducting and supplies enough Gate voltage to SCR2 to turn it on.

As a result, the current flows through SCR2 via R2 and SCR1 is turned off as both gate voltage and supply voltage are cut off. The Red LED is turned on indicating a full charge on the battery.

1. CMYK CIRCUIT IDEAS AUTO TURN-OFF S.C. DW IVEDI BATTERY CHARGER Y.M. ANANDAVARDHANA to energise electromagnetic relay RL1. Pushing switch S1 latches relay Relay RL1 is connected to the collec- RL1 and the battery cells start charg- T his charger for series-connected tor of transistor T1. Transistor T1 is ing. As the voltage per cell increases 4-cell AA batteries automatically driven by pnp transistor T2, which, in beyond 1.3V, the voltage drop across disconnects from mains to stop turn, is driven by pnp transistor T3. resistor R4 starts decreasing. When it charging when the batteries are fully Resistor R4 (10-ohm, 0.5W) is con- falls below 650 mV, transistor T3 cuts charged. It can be used to charge par- nected between the emitter and base off to drive transistor T2 and, in turn, tially discharged cells as well. of transistor T3. cuts off transistor T3. As a result, re- The circuit is simple and can be When a current of over 65 mA lay RL1 de-energises to cut off the divided into AC-to-DC converter, relay flows through the 12V line, it causes a charger and red LED1 turns off. driver and charging sections. voltage drop of about 650 mV across You may determine the charging In the AC-to-DC converter section, resistor R4 to drive transistor T3 and voltage depending on the NiCd cell transformer X1 steps down mains 230V cut off transistor T2. This, in turn, turns specifications by the manufacturer. AC to 9V AC at 750 mA, which is rec- transistor T1 ‘on’ to energise relay RL1. Here, we’ve set the charging voltage tified by a full-wave rectifier compris- Now even if the pushbutton is re- at 7.35V for four 1.5V cells. Nowadays, ing diodes D1 through D4 and filtered leased, mains is still available to the 700mAH cells are available in the mar- by capacitor C1. Regulator IC LM317 primary of the transformer through its ket, which can be charged at 70 mA (IC1) provides the required 12V DC normally open (N/O) contacts. for 10 hours. The open-circuit voltage charging voltage. When you press In the charging section, regulator is about 1.3V. switch S1 momentarily, the charger IC1 is biased to give about 7.35V. Pre- The shut-off voltage point is deter- starts operating and the power-on set VR1 is used for adjusting the bias mined by charging the four cells fully LED1 glows to indicate that the voltage. Diode D6 connected between (at 70 mA for 14 hours). After measur- charger is ‘on.’ the output of IC1 and battery limits ing the output voltage, add the diode The relay driver section uses pnp the output voltage to about 6.7V, drop (about 0.65V) and bias LM317 ac- transistors T1, T2 and T3 (each BC558) which is used for charging the battery. cordingly.
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page
Popular Searches: auto turn off battery charger mini, advantages of laser controlled on off switch, advantages and disadvantages and application of mobile cellphone charger using ic 555, abstract for auto turn off mobile charger, lm35dz lm358, advantages disadvantages of microcontroller based solar charger wikipedia, economiser adj,

[-]
Quick Reply
Message
Type your reply to this message here.

Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  well-spring some homemade barbecue backchat and moistureless rubs and the actuality 0 1,026 10-09-2019, 05:48 PM
Last Post:
  agent some homemade barbecue cheek and prosaic rubs and suit 0 942 10-09-2019, 07:04 AM
Last Post:
  pass some homemade barbecue coolness and arid rubs and module 0 898 09-09-2019, 06:35 PM
Last Post:
Wink disadvantages of plastic in malayalam essay 2 2,429 29-12-2018, 06:07 AM
Last Post:
  disadvantages of smart dustbin 0 644 27-10-2018, 03:47 PM
Last Post: Guest
  foot step bearing information advantages disadvantages application 0 684 21-10-2018, 08:54 PM
Last Post: Guest
  advantages n disadvantages of bhakra dam 0 652 03-10-2018, 08:04 PM
Last Post: Guest
  advantages and disadvantages mains failure alarm circuit in pdf 0 780 01-10-2018, 11:48 PM
Last Post: Guest
  performance appraisal methods adopted by bajaj auto india 0 592 30-09-2018, 01:07 PM
Last Post: Guest
  project report on battery level indicator pdf 0 1,892 25-09-2018, 05:50 PM
Last Post: Guest

Forum Jump: