Are all 18650 batteries the same voltage?

No - Not all 18650 batteries are the same voltage. The only thing the 18650 batteries have in common is the size - 18mm x 65mm, and they're all Lithium-ion batteries. Most 18650 cells have a voltage range of 2.5V to 4.2V. Different 18650 cells are made with different intentions. It is best to consider checking the capacity and voltage of the 18650 battery before purchasing. Mismatched batteries can be harmful to your device.

How many amps can the 18650 battery put? What are the factors that affect the battery voltage?

The 18650 battery produces 2,500mAh (2.5 amps) to 3,500mAh (3.5 amps). Higher amp output means more battery power. Consider this example: if you have a 4.2V 3,600mAh 18650 battery, it can power your device for one hour at 3.6 amps, or two hours at 1,800mAh.

Three main factors affect battery cell voltage:

Operating temperature - The battery cell voltage is related to the activity of the active material inside the battery. Therefore, the ambient temperature that affects the activity of the active material will also affect the battery voltage in a small range;

Load Power - Since the voltage and power of the battery are fixed values, the greater the load power (low resistance), the greater the required current, and the corresponding voltage will be reduced to make up for the reduced power. Excessive load may damage the battery;

Battery Life (or Health) - One way to detect a faulty or unsafe battery is to check its performance. When the battery is no longer safe to use, you will notice that it no longer retains its previous charge. This also means its voltage drops.

Simply put, the factors that affect battery voltage are operating temperature, load power, and battery life (or health).

How many volts are 4.2 18650 batteries? How many 18650 batteries are needed for 12v?

The nominal voltage of the 18650 battery is 3.7V, and the battery pack voltage is 7.4V when two 18650 batteries are connected in series. The maximum charging voltage of the 18650 battery is 4.2V, and the maximum voltage of two 18650 batteries in series can reach 8.4V (4.2 V x 2). These batteries must be connected in series. You'll need three 3.7V 18650s in series to get a nominal 12V. It is important to note that connecting cells in series will not increase the capacity of the battery pack, but will increase its voltage. On the other hand, connecting batteries in parallel will not increase the battery voltage, but will increase the capacity.

At what voltage is the 3.7 V battery dead?

When the 3.7V 18650 battery voltage drops to 3V, it will crash. This is because the protective plate stops discharging to prevent the battery from over-discharging. The 18650 battery has a shutdown voltage of 2.75V. In general, when the battery voltage drops to 0.875 times the nominal voltage (3.24V), it should be charged in time. On the other hand, a 4.2V 18650 battery can also be considered dead when the voltage reaches 3.0V.

What voltage is the 3.7V battery dead at?

It is important to note, however, that some 18650 batteries do not cut the circuit. Therefore, it should not be discharged beyond 3.0V, otherwise the battery voltage will drop rapidly, and may even cause irreversible damage to the battery due to overdischarge. When comparing 18650 batteries 4.2V and 3.7V, the logical conclusion is that the former is better than the latter. A 4.2V 18650 battery can support more loads or power a device for a longer period of time than a 3.7V battery.