LTC2943 IC is not providing exact battery voltage

General
1

Hi,

I am using LTC2943 IC to measure the battery voltage. I am getting the voltage value but it doesn’t seem to be perfect.
For example, If my battery voltage is 7.45V then It will show 7.2V. It always shows the voltage lesser than it actually is. Strangely, The difference always remains 0.2V.
I am using Android 7.1 SDK and I have downloaded the ltc2943 driver from the official site.
Everything else seems to be all right.

Thanx in advance.

2

If you want to receive help from the community we need a bit more to go on, can you share your circuit diagram, Rsense value and prescaler factor setting. Are you measuring a single cell battery or a multi-cell battery. How many cells do you think you have in your battery and are you sure? With a PP3 9V I have had to open the case before because sometimes there are 8 cells and others there are 7 cells.

3

I am using firefly AIO 3399J board for development and as far as circuit diagram is concerned, I am using DC1812A - Multicell Battery Gas Gauge with Temperature,Voltage and Current Measurement eval board.

Predefined Parameters:

  1. lltc,resistor-sense = <20>;
  2. lltc,prescaler-exponent = <5>; /* 2^(2*5) = 1024 */

I am measuring multi-cell battery(2S2P - 18650,2600mAh).

I have shared couple of useful links below:
https://pdf1.alldatasheet.com/datasheet-pdf/view/706707/LINER/LTC2943_15.html

4

@Parth9731 Which Particle device are you using with the DC1812A?