Battery requirement for Arduino Nano and sim800l/SIM900a module

I am new to Arduino. I have worked on one Arduino project which need to send 4-5 SMS and 3-4 times data connection at once and at about 4 times in a day. Probably it turns out to be about 2-3 minutes each time and four times a day. The project unfortunately need to consider the locations without electricity. hence, I had to power it with 12V lead acid battery and corresponding solar panel (of course with suitable buck voltage controllers). However, I feel that this power option is costly as well as oversized.
I need support of the experts in the community to help me in finding the optimum, fail-safe and economic power solution. Can Lipo be an option for me, if yes, what would be the specifications of battery and solar panel and what will be the charging method to charge LIPO using solar panel? Please also let me know, if any approach is possible to reduce the power consumption.
Thanks in advance

That cannot be answered until your load requirements are known. That with the operating hours and safety factors you now have a realistic load, from that you can determine what size battery you will need. You will also have to factor in no solar and low solar power days. You can then pick the battery size and probably chemistry. You then need to purchase or build appropriate charging system. That should get you to the prototype stage. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!


If you do not need your GSM module is always ON, I recommend to power off the GSM module. I think there is a PWRKEY pin on the module which is internally pulled up, just you need pull-down for 1 sec. Or, there are sleep modes are available on the AT command list. Sleep modes and turn on/off will help your battery life if you need the GSM module for several times in a day. In another way, if you have a different power source for the GSM module, turn on/off that module can extend battery life significantly.

Another good way to extend your battery is a deep sleep mode of your microcontroller. However, in this step, there are different factors affecting battery life such as Quiescent Current of your power supply of microcontroller.

For the battery choice, Li-Po or Li-Ion batteries are recommended in the hardware design manual of the GSM module. There are several advantages to use them. For example, the modules are operating between 4.2v -3.8V which is the range of Li-Po / Li-ion Battery voltages. And, some modules of SIMCOM(I know SIM808 has it, but SIM900 MIGHT have it) has an internal battery charger for Li-po/ Li-Ion battery. Apart from these points, if you power the gsm and microcontroller with the same voltage, you don't need level shifters. Therefore, 4.2V-4V can be a good choice in my point of view.

Another important point is using capacitors at the power line of the GSM Module. The hardware design manual recommends different capacitors for different purposes. When you design your circuit, consider it is a power-hunger beast module

Powering GSM modules is a crucial point of the design since it is said that the module can draw 2A peak current. I suggest using a reliable power source with low Quiescent Current

You can reach SIMCOM GSM modules' documents via below the link. Hardware design manuals and AT command List are a great source for what you need

Good luck