.1. Power Supply Solution
Terminal device has to operate for a long time without AC mains supply. Hence device system needs super capacity batteries to supply power. The power supply range of the GSM/GPRS module is 3.3～4.6V,and the power for MCU is 3.3V or lower voltage. Since the battery is used as power source for device,battery capacity selection and power circuit design play an important role in reducing power consumption of whole system.
1.2. Battery Type
Considering the long-term effective working of the battery, super capacity Lithium-thionyl chloride(Li-SOCl2)is needed. Lithium-thionyl chloride (Li-SOCl2) can not only provide the maximum energy ratio and voltage, but also have preferable discharge characteristic and little self-discharge.
Generally, super capacity Lithium-thionyl chloride (Li-SOCl2) can be classified into power type and energy type. For energy type battery, its capacity is high (e.g. ER34615 3.6V/19Ah),but maximum continuous discharge current is quite lower. And power type battery can output larger current (e.g.ER34615M 3.6V/13Ah). Besides these two typical batteries, there is another battery pack (e.g.ES-
ER34615+SPC 1550 3.6V/19Ah) which is composed of an energy battery ER34615 and a super pulse capacitor SPC1550. This battery pack can overcome the defect of energy type that cannot provide high pulse current.
The comparison of the related parameters between these three types is shown as below:
Battery Capacity Requirement Assessment
In practice,it is important to choose a suitable capacity of battery for low consumption device; also, it is difficult to calculate the exact requirement for battery capacity.
It can be estimated by following ways.
The power consumption of the device can be calculated in two modes: sleep mode and working mode.
No matter which mode the device works, the power consumption of device can be divided into four parts:
MCU control system, GSM/GPRS module system, self-discharge of battery and other external controlledtarget (e.g. valves).
Here is an example showing a calculation method of power consumption as follows, assume the device with 10 years of working time.
Post time: 2021-03-10 10:32:42
