Low cost DC supply solution, 3.7V 1100mAh Li-Ion Battery (LI-3.7-1100)

Introduction

Figure 1: The appearance of 3.7V 1100mAh Li-Ion Battery (LI-3.7-1100)

3.7V 1100m Ah Li-Ion Battery (LI-3.7-1100) is a typical Lithium Ion rechargeable battery in cylindrical shape that offers 1100mAh actual capacity (although it is labelled 3000mAh by the OEM).  It is a very low cost DC supply solution (low discharge rate), hence suitable in electronic projects or small mobile robots that do no require high discharge current. Also, it comes with an integrated protection PCB to prevent over-charged or over-discharged condition. The LI-3.7-1100 battery is 18650 sized with 18 mm in diameter and 67.5 mm in length. Its nominal voltage of a is 3.7V (will be at about 4.2V when fully charged). Hence, users can combine 2 units or 3 units of them to provide nominal voltage 7.4V or 11.1V.

Similar to other batteries, LI-3.7-1100 battery will become flatted after been used as supply of an electronic project for some period. Somehow, as mentioned previously, it is rechargeable and its specialized charger is shown in Figure 2 below.

Figure 2: The appearance of Dual 18650 Li-Ion Battery Charger (LI-CR-18650-2)

Dual 18650 Li-Ion Battery Charger (LI-CR-18650-2) is a low cost dual slot 18650 sized Li-Ion battery charger that able to charge your 18650 Li-Ion independently ( maximum 2 batteries at the same time). It is integrated with separate LED for each slot to indicate the charging status for batteries placed in. The input voltage of this charger is AC 100-240V with 50 or 60 Hz while its charging voltage is DC 4.2V with 1000mA for each battery. A guide on how to use the LI-CR-18650-2 battery charger to recharge LI-3.7-1100 batteries is provided in the next section.

Section 1: Recharge LI-3.7-1100 batteries using LI-CR-18650-2 battery charger

1. Without plugging the battery charger to AC supply first, please place in the batteries (required to be recharged) to charger slots by following the orientation shown inside the slots as shown in Figure 3 below.

  

   (a) Charger terminals and batteries placing                      (b) The actual placing orientation of batteries in charger

                  orientations as indicated                                                            slots

Figure 3: Place in the batteries to charger slots at correct orientations

2. As the batteries are ready placed in slots,  plugging the charger to AC supply and then turn on the charger. The LED (indicator) for each slot will light up in red color and this means the batteries are in being charged process.

Figure 4: The batteries are in being charged process

3. Since each slot is provided with its own LED (indicator), when the battery placed in a particular slot is fully charged, the corresponding LED (indicator) color will changes from red to green to indicate the fully charged status.

Figure 5: The batteries are fully charged

4. Remove the fully charged batteries from the charger and place in other remaining batteries (that requires recharging) into charger slots to repeating recharging process again.

*When the charger is in “on” state and no batteries present in the slots, the LEDs (indicators) will light up in green color as default.

In the next section, there will be a demonstration on using LI-3.7-1000 batteries (combined with some related accessories) as DC supply in few example electronic projects.

Section 2: Using LI-3.7-1000 batteries as DC supply in electronic projects

The most basic accessory for LI-3.7-1000 battery is the 18650 Battery Holder which available in 3 sizes which are 1×18650 (CN-BA-18650-01), 2 x 18650(CN-BA-18650-02) or 3 x 18650(CN-BA-18650-03) to accommodate 1, 2 or 3 units of LI-3.7-1000 batteries correspondingly. The battery holder will facilitate the placement of batteries in electronic projects (for example on body of robot) while extending out the supply of batteries through the wires attached to it.

                      

                    (a) 1 x 18650                            (b) 2 x 18650                          (c) 3 x 18650

Figure 6: Available 18650 battery holders

Figure 7: Extend out wires of a battery holder

Well, let’s start to see how the LI-3.7-1000 batteries used as DC supply in some electronic projects in the following sections.

Project 1 : Arduino with LCD display

Most of Arduino mainboards are integrated with DC adapter socket where it can be connected to an AC to DC adapter for the board power supply. Two example Arduino mainboards (with integrated DC adapter socket) that will be used for demonstration in this section are BBFuino and Duemilanove as shown in Figure 8 below.

     

                                         (a) BBFuino                                                                                                  (b) Duemilanove     

Figure 8: Arduino mainboards installed with DC adapter socket

A. Using LI-3.7-1000 batteries as DC supply of BBFuino for LDC display

1. To use LI-3.7-1000 batteries to supply power to BBFuino board, a DC Jack to DG126 Converter (CN-126-DC) as shown below is required. Of course, the battery holder is needed too.

Figure 9: DC Jack to DG126 Converter (CN-126-DC)

2. Based on the user manual of BBFuino which can be downloaded from Cytron website under product page, BBFuino, the recommended input voltage, Vin to BBFuino board is DC 7-12V. Only two LI-3.7-1000 batteries are needed to provide nominal voltage at 7.4V or about 8.4V (when the batteries are fully charged) which is in the recommended range. Thus, a 2 x 18650 battery holder is used.

*User is also allowed to combine three LI-3.7-1000 batteries to provide nominal voltage at 11.1V or about 12.6V (when the batteries are fully charged) as DC power supply to BBFuino board.

3. First, connect the extend out wires of the battery holder to DC Jack to DG 126 Converter (CN-126-DC) as shown below. The positive terminal wire (red) of battery holder is connected to positive(+) terminal of the CN-126-DC converter while its negative terminal wire (black) is connected to negative(-) terminal of the CN-126-DC converter. The wires are screwed into the terminal block of CN-126-DC converter.

      

Figure 10: Connections between the battery holder / and the CN-126-DC converter

4. Place in the LI-3.7-1000 batteries into the battery holder by following the orientations indicated in the slots. Until here, the setup for extending out supply power of LI-3.7-1000 batteries is considered complete and it can be connected to BBFuino board to power it.

  

(a)  Batteries placing orientations as indicated              (b) The actual placing orientation of batteries in battery holder


Figure 11: Place in the batteries to battery holder at correct orientations

5. The BBFuino board used in this demonstration is pre-installed with a 2 x 8 LCD as shown below.

Figure 12: BBFuino board with pre-installed 2 x 8 LCD

*Please refer to user manual of BBFuino which can be downloaded from Cytron website under product page, BBFuino for extra related information.

6. Connect the DC jack of CN-126-DC converter to the DC adapter socket of BBFuino board. As the result, the BBFuino board as well as LCD are powered up and display the string “Hello World!!” on LCD based on the program loaded into the onboard microcontroller..

Figure 13: Connect the DC jack of CN-126-DC converter to the DC socket of BBFuino board

Figure 14: The BBFuino board is powered up with the DC supply from LI-3.7-1000 batteries for LCD displaying

B. Using LI-3.7-1000 batteries as DC supply of Duemilanove for LDC display

1. Based on the user manual of Duemilanove board which can be downloaded from Cytron website under product page, Duemilanove, the recommended input voltage, Vin of Duemilanove board is same as BBFuino board, which is DC 7-12V, thus only  two LI-3.7-1000 batteries are needed.

*User is also allowed to combine three LI-3.7-1000 batteries to provide nominal voltage at 11.1V or about 12.6V (when the batteries are fully charged) as DC power supply to Duemilanove board.

2. The setup for extending out supply power of LI-3.7-1000 batteries from previous section (Section A) can be reused.

3. The only difference is the Duemilanove board will  be combined with the Arduino-LCD keypad shield (ARDUINO-LCD) as shown below for displaying purpose. This shield is designed to be fit suitably (stacked at top) to the Arduino mainboards like Arduino Duemilanove and Arduino Uno.

Figure 15: Arduino-LCD keypad shield

*Please refer to user manual of ARDUIINO-LCD shield which can be downloaded from Cytron website under product page, ARDUINO-LCD shield for extra related information.

4. Fit in the ARDUINO-LCD shield to the Duemilanove board (stacked at top) through the header (Female) on the Duemilanove board.

     

                  (a) Top View                                       (b) Side View

Figure 16: The Duemilanove board combined with ARDUINO-LCD shield  

5. Connect the DC jack of CN-126-DC converter to the DC adapter socket of Duemilanove board. As the result, the Duemilanove board as well as ARDUINO-LCD shield are powered up and display the string “Welcome to Cytron” on LCD based on the program loaded into the onboard microcontroller.

Figure 17: Connect the DC jack of CN-126-DC converter to the DC adapter socket of Duemilanove board

Figure 18: The Duemilanove board is powered up with the DC supply from LI-3.7-1000 batteries for LCD displaying

Project 2: SK40C with LCD display (Using LI-3.7-1000 batteries as DC supply of SK40C for LDC display)

1. The Enhanced 40-pins PIC Start-Up Kit (SK40C) is designed to offer an easy-to-start board for PIC MCU users. This board comes with basic elements for users to begin project development  and it offers plug and use features too. SK40C is also integrated with DC adapter socket where it can be connected to an AC to DC adapter for the board power supply as shown below.

Figure 19: SK40C with integrated DC adapter socket

2. Based on the user manual of SK40C which can be downloaded from the Cytron website under the product page, SK40C, the recommended input voltage,Vin which is DC 7-15V. Different from previous section, we will demonstrate using three LI-3.7-1000 batteries to provide nominal voltage 11.1V or about 12.6V (when the batteries are fully charged) as DC power supply to SK40C board.

3. The setup for extending out supply power of LI-3.7-1000 batteries is similar to that in the previous project and only the battery holder size is changed to 3 x 18650 to accommodate three batteries.

4. The SK40C board used in this demonstration is pre-installed with a 2 x 16 LCD as shown below.

Figure 20: SK40C with pre-installed 2 x 16 LCD

*Please refer to user manual of SK40C which can be downloaded from the Cytron website under the product page, SK40C for extra related information.

5. Connect the DC jack of CN-126-DC converter to the DC adapter socket of SK40C board and turn “on” the toggle switch of the SK40C . As the result, the SK40C board as well as 2 x 16 LCD are powered up and display the string “Welcome to Cytron” on LCD based on the program loaded into the onboard microcontroller.

Figure 21: Connect the DC jack of CN-126-DC converter to the DC adapter socket of SK40C board

Figure 22: The SK40C board is powered up with the DC supply from LI-3.7-1000 batteries for LCD displaying

Project 3: Educational Mobile Robot 2.0 for line-following

1.  Educational Mobile Robot 2.0 (EDUBOT2) is basically a complete set of the Mini Robot Controller (MC04) bundle with aluminum base, 150:1 Micro Metal Gearmotor (SPG10-150k), wheel, and Auto calibrate line sensor (LSS05) to become an education mobile robot. The robot controller is preprogrammed with sample source code and user can start to run the EDUBOT without any programming.

Figure 23: Educational Mobile Robot 2.0 (EDUBOT2)

2. Based on the user manual of EDUBOT2 which can be downloaded from the Cytron website under product page, EDUBOT, the recommended input voltage supply, Vin the EDUBOT2 is DC 7 -12V. The voltage source will supply power to on the board microcontroller, LCD, LSS05 analog sensor and other components and it can be extended supply power to motor of the EDUBOT.

3. Hence, only two LI-3.7-1000 batteries are needed to provide nominal voltage at 7.4V or 8.4V (when the batteries are fully charged) which is in the recommended range.

4. For the demonstration in this section, the input voltage, Vin will be extended for motor power of the EDUBOT. Thus, please move the jumper at JP5 at position as indicated below for this purpose.

Figure 24: The position of jumper at JP5 for extending Vin for motor power

5. There are 2 terminals may be used to supply power to EDUBOT2. One of them is the DC adapter socket where the user may use the standard AC to DC adapter DC 12V to supply the power into EDUBOT. In this case, The setup for extending out supply power of LI-3.7-1000 batteries from previous demonstrated projects can be reused by connecting the DC jack of CN-126-DC converter to the DC adapter socket of the EDUBOT as shown below.

     

            (a) DC adapter socket                          (b) Connect the DC jack of CN-126-DC converter to the

                                                                                   DC adapter socket of EDUBOT

(c) Overview

Figure 25: Connection of LI-3.7-1000 batteries to supply power to EDUBOT through the DC adapter socket

*User is also allowed to combine three LI-3.7-1000 batteries to provide nominal voltage at 11.1V or about 12.6V (when the batteries are fully charged) as DC power supply to EDUBOT.

6. While another terminal is the 2 ways blue terminal block where the user may use terminal wires from battery and connect them to blue terminal block to supply power to EDUBOT2. Do ensure polarity of the supply is correctly installed. The (+) sign terminal should be connected to positive(+) terminal of battery and vice versa for the (-) terminal. In this case, the CN-126-DC converter is not necessary and can be removed from the previous setup for extending out supply power of LI-3.7-1000 batteries. The wires from the battery holder of LI-3.7-1000 batteries are connected directly to the blue terminal block in this way, where the positive terminal wire (red) of battery holder is connected to positive (+) terminal of the blue terminal block and vice versa for the negative terminal wire of battery holder as shown below.

     

         (a) 2 ways blue terminal block                          (b) Connect wires of battery holder to blue terminal block accordingly


(c) Overview

Figure 26: Connection of LI-3.7-1000 batteries to supply power to EDUBOT through the blue terminal block

*There should be ONLY ONE power source connected to EDUBOT2, is either through DC adapter socket or the blue terminal block. Please DO NOT connect both.

7. In this demonstration, the DC adapter socket is used as terminal to supply power to EDUBOT2. Turn on the EDUBOT through the “ON-OFF” slide switch on the robot controller. The power indicator (green LED) will light up, the LCD will turn on and the EDUBOT2 is ready for operations. Please refer to the user manual of EDUBOT2 which can be downloaded from the Cytron website under product page, EDUBOT for choosing any of the available modes to be executed.

     

Figure 27: Conditions of power indicator and LCD when the EDUBOT is turned on

8. A short video on using low cost LI-3.7-1000 batteries as DC supply power to all projects demonstrated above is embedded below.

That’s all from me. Please extend the usage of 3.7V 1100mAh Li-Ion Battery (LI-3.7-1100) batteries in your electronic projects. See ya!

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