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Power System for Arduino Project

nicolaoscon96

Hello guys

 

 

I'm thinking of a system for my car (like an alarm but it will be able for two ways communication with the car and the phone) it will be based on an Arduino Uno along with a GSM shield and GPS)

 

 

I figure everything out but am stuck with the power system> I don't want to dedicate connect it to the car's wiring because if I leave it for a day or so probably will drain my battery. I want to make something "hybrid" like using both my car's wiring and 2 or 3 18650 batteries with BMS.

 

 

The idea is like this.

 

 

        V

        V

 

 

when the car is turned on the system will turn off and the battery of the system will start to charge(if it is night by using the car's battery and if it's day think of solar or keep it with car's electronics).

 

when the car is turned off then the system will start and it will use a few 18650 batteries. (If am not mistaken I believe it will hold for a night till I start the car)

 

 

Power need: 12v

Power Drawing: When running it on 12v it draws around 160mAh at the start-up and then around 100mAh

 

 

Any ideas on how to do it?

 

Thanks in advance

Nikolaos Konstantinou

  • Keep in mind that fully charging one 18650 battery requires about 4 hours. Therefore, daily commuting could be too short to keep the battery charged and I wouldn't depend on solar power as parking your car on underground parking, under a tree or wherever on a cloudy day means no charging.

    To use 18650 batteries for a 12V power supply you need 4 units to get the voltage (exactly - it'll be more like 14.4V, but with 3 you'll get only 10.8V). Charging such a set is not a trivial task, as the batteries have to be balanced (as they're connected in series) and it requires a dedicated for such a task charging module. Charging multiple 18650 batteries means quite decent current and may require good wiring and some cooling as the charging board probably will be getting warm. Increasing the capacity of the set by adding second set in parallel doesn't make the charging situation easier.

     

    Some of the Adafruit (probably not only their, I just have these ones in mind but you can look for other manufacturer) boards have got built-in connector for LiPo battery, maybe you should consider using such board (https://learn.adafruit.com/adafruit-feather-32u4-adalogger/power-management ) as it would deal with some of the work for you?

     

    Moreover, keep an eye on the temperatures accepted by the batteries, no matter which batteries you will choose. (What are the advantages of 18650 lithium-ion battery? What is its operating temperature range? - Benzo Energy / China be… ) On a sunny day the temperature inside a car can easily reach 60*C, not to mention the temperatures in the engine compartment.

     

    Maybe you could reduce the power consumption by enabling some sleep mode and possibly short duty cycle?

    150mA at 12V seems like quite a lot of power for an Arduino unless you're powering a 12V relay or somehting like that... (150mA@12V is a typical characteristics for a car relay's coil)