I haven't yet tried to power the Arduino on some battery source instead of my laptop or some other USB power source. So I've done a little bit of searching and I've seen 2 ways people do it:
Connect battery to the power jack using the adapter for it
Connect battery to the Vin and GND on the Arduino
Is there any difference between the 2? Also, I've read some people saying not to use the classic 9V battery, because it drains very quickly. Is that true? Finally, any recommened Li-ion batteries? Are there any other measures to take to ensure long-lasting life on 1 charge?
Is there any difference between the 2?
Yes. The power jack goes through a diode so connecting the power backwards won't hurt the Arduino. The VIN pin bypasses that diode and goes straight to the 5V regulator.
Also, I've read some people saying not to use the classic 9V battery, because it drains very quickly. Is that true?
Yes. A classic 9V "transistor" battery has very low capacity. It might run your Arduino project for a day at best or less than an hour at worst.
Finally, any recommened Li-ion batteries?
A single LiPo cell (3.7V) going to the +5V pin will power an 8 MHz Arduino. To run at 16 MHz you are supposed to use 3.78V or higher. You can use a boost converter to boost the voltage to 5V on the +5V pin but there will be some loss (typically 5 to 20%) in the conversion.
Two cells in series (7.4V) can be connected to the VIN pin or power jack. That will be using the built-in 5V regulator which will consume 32% of the power. To conserve energy you can use a buck converter to drop the voltage to 5V on the +5V pin but there will be some loss (typically 5 to 20%) in the conversion.
Many people use cellphone charger packs. These charge via USB and have a USB socket for charging cellphones.
Are there any other measures to take to ensure long-lasting life on 1 charge?
Buy a battery with a high capacity, typically measured in milliamp-hours. Note: Expect inexpensive cellphone chargers from Asia to be lying when they claim 10,000 or 100,000 mAh.
Is there any difference between the 2?
Yes. The power jack goes through a diode so connecting the power backwards won't hurt the Arduino. The VIN pin bypasses that diode and goes straight to the 5V regulator.
Also, I've read some people saying not to use the classic 9V battery, because it drains very quickly. Is that true?
Yes. A classic 9V "transistor" battery has very low capacity. It might run your Arduino project for a day at best or less than an hour at worst.
Finally, any recommened Li-ion batteries?
A single LiPo cell (3.7V) going to the +5V pin will power an 8 MHz Arduino. To run at 16 MHz you are supposed to use 3.78V or higher. You can use a boost converter to boost the voltage to 5V on the +5V pin but there will be some loss (typically 5 to 20%) in the conversion.
Two cells in series (7.4V) can be connected to the VIN pin or power jack. That will be using the built-in 5V regulator which will consume 32% of the power. To conserve energy you can use a buck converter to drop the voltage to 5V on the +5V pin but there will be some loss (typically 5 to 20%) in the conversion.
Many people use cellphone charger packs. These charge via USB and have a USB socket for charging cellphones.
Are there any other measures to take to ensure long-lasting life on 1 charge?
Buy a battery with a high capacity, typically measured in milliamp-hours. Note: Expect inexpensive cellphone chargers from Asia to be lying when they claim 10,000 or 100,000 mAh.
Thank you very much for your answer!!! MUCH appreciated :D!