TILEBOX battery voltage problem

lanhua

TILEBOX battery voltage problem [Copy link]

 

TILEBOX battery voltage problem:

My TILEBOX battery voltage

The display value of the connected mobile phone is 3.98V, 95%

The multimeter measured value was 4.14V

The difference is 0.16V

How to adjust or correct?

qwqwqw2088

This software is connected to the battery display of the mobile phone, which is related to the protection circuit. Correction requires disconnecting the protection circuit.

The software is used to obtain information such as battery power, charging status, battery status, etc.

lanhua

qwqwqw2088 posted on 2022-1-16 18:54 This software is connected to the battery display of the mobile phone, which is related to the protection circuit. Correction requires disconnecting the protection circuit. The software is used to obtain the battery power and charge...

One more question:

Every time you connect to a mobile phone (no matter how much power is left in the battery), you must plug it in to charge before the connection can be made, otherwise TILEBOX will not respond at all.

se7ens

Did you connect a load when testing the battery voltage with a multimeter?

If not, the difference is normal.

If so, you need to determine whether the multimeter is calibrated, otherwise it is a problem with the mobile phone software.

littleshrimp

From the schematic diagram, we can see that the lithium battery measurement is done by STBC02 outputting the lithium battery voltage through the BATMS pin, and then connected to the PC4 of the microcontroller through AN_VBATT after voltage division by R33 and R34.

In the STM32CubeMX project of SensorTile.box, we can see that PC4 is IN13 of ADC1, which means that the voltage is directly collected by ADC after voltage division.

The main factors that may cause measurement errors are the accuracy of the voltage divider resistor and the impedance of the ADC during measurement. You can use a multimeter to measure the voltage at AN_VBATT, calculate the actual lithium battery voltage through voltage division, and then compare it with the voltage displayed on the mobile phone to see if the error is caused by the accuracy of the voltage divider resistor.

qwqwqw2088

lanhua posted on 2022-1-16 21:47 There is another question: Every time you connect to a mobile phone (regardless of how much power is left in the battery), you must first plug it in to charge before you can connect, ...

You have to plug it in to charge before you can connect it, otherwise TILEBOX will not respond at all.

How long is this battery?

It seems that the battery is over-discharged.

Over discharge requires charging and activation before re-discharging.

lanhua

littleshrimp posted on 2022-1-17 10:21 From the schematic diagram, we can see that the lithium battery measurement is through STBC02 outputting the lithium battery voltage through the BATMS pin, and then through R33 and R34 after voltage division through AN_VB ...

Thank you for the insightful analysis!

lanhua

qwqwqw2088 posted on 2022-1-17 10:49 You have to plug it in and charge it before you can connect it, otherwise Tilebox will not respond at all. How long is the battery? Like...

The battery really needs to be activated!

Because this box has no power switch, it may be completely empty.

littleshrimp

lanhua posted on 2022-1-17 14:35 Thank you for the insightful analysis!

In addition, the reference voltage error of the ADC will also affect the accuracy of the measurement. The VREF+ in the schematic diagram uses +2.7V.

This part of piezoelectricity is obtained by LDO through the voltage divider resistor. If you use an external voltage, you also need to determine the actual voltage of this +2.7V.

If the code uses an internal reference, the accuracy of the internal reference voltage also needs to be considered.