So, three Ni-Cd or Ni-MH cell in series can be connected directly to power up an ESP module. So, connecting three we get 3.9 volts which I think will not create any problem in ESP module. The open circuit voltage of a fully charged Ni-Cd can be 1.3 volts. So, if we connect three cell in series than total output voltage will be 3.6 volts which is within the tolerable limit of an ESP module. The output voltage of both Nickel-metal hydride & Nickel-cadmium cell is 1.2 volts. So, Li-ion battery should not directly connect to ESP module. The output voltage of a Lithium cell is 3.7 volts and capacity depends on the size of the cell.įrom the above discharge curve of a Li-ion battery, it is clear that though the nominal voltage of a Li-ion battery is 3.7 volts, a fully charged Li-ion battery voltage starts from 4.2 volts which is more than the tolerable limit of an ESP module. Lithium-ion batteries are available in different size and dimension. The most common rechargeable battery used today is Lithium-Ion battery. A parallel capacitor can give a good result but required some experimentation to know the exact response. So, a standalone coin cell is not enough to provide sufficient current to power up an ESP module. Most of the coin cell cannot provide more than 20mA! The average current taken by an ESP module is 80mA. But before taking the final decision we should consider another important parameter of the battery, maximum discharge capacity or maximum current supply capacity in a simpler term. A typical Lithium coin cell has the output voltage of 3 volts which is perfect for powering up an ESP module. Lithium batteries are most common in button or coin form. But, we can use a Lithium battery to power up an ESP module. So, in a single sentence, I can say that we should not use two Zinc-carbon or Alkaline cells in series to power up an ESP module if we don't like to keep 75% energy unused in the battery before throwing it. We can get at least 70% energy from a Lithium battery before going cut-off level. If we use Lithium battery we will get an interesting result. If we use two Alkaline battery we can use at best 30% which is approximately same as Zinc-carbon battery. From the discharge curve below it is clear that for a zinc-carbon battery about 25% capacity can be used before the voltage reduced to 1.25 volts. If we connect two battery in series the ESP will live until each battery voltage drained to 1.25 volts. Now, let calculate the run time of two batteries connected in series. So, at least two battery with a series connection (to make 3 volts) is required to power up an ESP module because according to data sheet at least 2.5 volts is required to power up an ESP module. Zinc-carbon and Alkaline type AA and AAA size battery (or cell) have an output voltage 1.5 volts. First, consider non-rechargeable AA & AAA size battery because they are most commonly available and inexpensive one. I mentioned the possible battery technology that can be used to power up ESP module. Nickel-cadmium battery: Ni-Cd has nominal cell voltage 1.2 volts and commonly available sizes includes AA and AAA. Nickel–metal hydride battery: Ni-MH batteries have a nominal output voltage 1.2 volts and most common sizes are AA, AAA. Li-ion battery is available in different size and capacity including AA, AAA, 18650. Lithium-ion battery: Lithium-ion is the most common rechargeable battery today and delivers about 3.7 volts. Lithium batteries are also available in coin, and button form with an output voltage 3V.Īlkaline battery: dry cell primary battery that delivers about 1.5 volts and most common sizes are AA, AAA, and 9V. Lithium batteries: dry cell primary battery that delivers about 1.5 volts and most common sizes are AA and AAA. Zinc-carbon battery: most commonly available and the most inexpensive dry cell primary battery that delivers about 1.5 volts and most common sizes are AA, AAA, and 9V. Now, let us discuss the most commonly available battery types used in electronics. So, for the esp8266 battery discharge rate should not be less than 170mA. An esp8266 chip can draw maximum 170mA current. So for safely running an ESP8266 device, the battery voltage should be within 2.5 to 3.6V. Minimum voltage for stable operation is 2.5V and the maximum allowable limit is 3.6V. From the datasheet, we find nominal voltage of the esp8266 is 3.3V. Before choosing a battery we need the understand about voltage and current rating of an ESP8266.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |