Fuel Gauge IC for Primary Cell Monitoring

Projects General Guidance
1

I am currently developing a humidity sensor-based wireless sensor node powered by a primary battery, either lithium thionyl chloride (LiSOCl₂) or lithium manganese dioxide (LiMnO₂). The objective is to operate the sensor for 5 to 10 years without battery replacement. To monitor the remaining battery life, I plan to integrate a fuel gauge IC. The sensor will be active for 20 µs, during which it will take humidity measurements, and will remain in sleep mode for the rest of the cycle. The measurement interval can be 5 minutes, 10 minutes, or 15 minutes.

Currently, the active current of the sensor module is 20 mA, and the sleep current is 60 µA.

My requirements are:

  1. Very low active and sleep current.
  2. Should be able to go in sleep mode during the sleep time of the sensor without affecting the accuracy.

Can anybody suggest me the Fuel Gauge IC which meets my requirements.

Thankyou

2

If you know the power consumption of your system (Watts) and the battery capacity (Watthours) then there is no need for a fuel gauge.

In any case it would be wise to make these calculations beforehand to see if your battery will actually last 10 years.

First determine how much power your system uses:
Power (W) = voltage (V) x current (A)

Then find your battery capacity:
Capacity (Wh) = mAh x nominal voltage

Divide battery capacity by system power to find out how many hours it will last:

Capacity (Wh)/Power(W) = hours.

(no advance calculus need)

Consider using a TPL5110 ot TPL5111 to reduce the sleep current to 1uA or less

4

Are those current values datasheet or actual measured with an appropriate meter (NOT VOM).

5

Curious which humidity sensor can do that in that short time.
A DHT11/22 needs 1 to 2 seconds.
SHT 20,21 sensors need 15ms power-up time and additional I2C communication time.
Leo..

6

I am currently developing a humidity sensor-based wireless sensor node powered by a lithium thionyl chloride (LiSOCl₂) battery. The goal is to operate the sensor for 5 to 10 years without replacing the battery. To monitor the remaining battery life, I plan to integrate a fuel gauge IC.

The sensor is active for 20 ms during each measurement cycle and remains in sleep mode for the rest of the time. The measurement interval can be 5, 10, or 15 minutes. The active current of the sensor module is 20 mA, and the sleep current is 60 µA.

In each transmission, I would like to send both the humidity reading and the remaining battery level in percentage.

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I have the following questions:

  1. Will I be able to monitor the remaining battery life in percentage or State of Charge (SOC)?
  2. Can the fuel gauge IC enter sleep mode during the sensor’s sleep period without compromising accuracy?
  3. I require very low active and sleep current from the fuel gauge.

Is the LTC3337 suitable for this application? If not, could you recommend a more appropriate fuel gauge IC that meets these requirements?

Thank you.

pert 8

I have merged your cross-posts @d2c2105.

Cross-posting is against the Arduino forum rules. The reason is that duplicate posts can waste the time of the people trying to help. Someone might spend a lot of time investigating and writing a detailed answer on one topic, without knowing that someone else already did the same in the other topic.

Repeated cross-posting can result in a suspension from the forum.

In the future, please only create one topic for each distinct subject matter. This is basic forum etiquette, as explained in the "How to get the best out of this forum" guide. It contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

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