Before connecting to the circuit, the voltage generating from the coin cell is 5.5v.
The voltage generating from the coin cell and supplying to andruino and lcd is approx 0.7V.
Coin cells are low current devices. They can't supply enough current to power the Arduino. Might have to use 6 or more in parallel to supply enough current. Would be better served with AA's or AAA's., but they will discharge rather quickly.
I am using two PANASONIC - BR-2032/HFN - CELL, LITHIUM COIN, 3V (190mAh) to power up Arduino and alpha numeric LCD.
Before connecting to the circuit, the voltage generating from the coin cell is 5.5v. The voltage generating from the coin cell and supplying to Arduino and lcd is approx 0.7V. I am unable to understand why the voltage is going down to 0.7V.
Please tell me whether i have to use coin cell of 1000mAh battery capacity or any other option. I cant use AA or AAA batteries in my project.
Lithium coin cells (3V) are often rated at 1mA or less - totally inadequate for this purpose.
To get enough current from that small battery you could actually use something like Joule's Thief circuit.