# Problem with power on when a battery is below 3.0 V and connected ti main power

### 11 thoughts on “Problem with power on when a battery is below 3.0 V and connected ti main power”

1. If the telit is connected to main power but if
it has connected a battery below 3.0 V, it starts to the batt charge
process and delays the execution of python.

My problem is that the PY is not executing until the voltage in
the battery is over 3.0 V. Sometimes it takes 2 o 3 minutes  to starts
executing the python code. Is this behavior normal or we have something
wrong in our circuit?

Regards,

Luis

1. Cosmin Buhu says:

What firmware Luis?

1. Cosmin,It’s 07.03.702

thank you for your prompt response.

1. Cosmin Buhu says:

The Extended Operating Voltage Range of the module in question is from 3.22V to 4.50V, so the behavior encountered from the customer is normal
In similar cases we suggest to monitor from python script the voltage present on VBATT pin (by AT#CBC command) and then if the voltage falls below
3.3V signal that is required the battery charging.

1. Cosmin,

If we have 4.3 V In CHARGE pin and we have a Li-ion battery with voltage below 3.0V connected to VBATT then the python code doesn’t execute until the voltage in VBATT is over 3.15 V ( It takes around 2 minutes until the telit module recharges the battery to a voltage over 3.15V).

Note that :

If there is no battery the python code executes normally

If the Voltage in the Li-ion battery is 3.15 or greater the python code executes normally

Is that behaviour normal?

2. Cosmin,

This is the case:

We turn our power supply off then we turn power supply ON and then we can measure:

The voltage in CHARGE PIN is 4.2 V,

We have a
Li-ion battery with voltage under 3.1V connected to VBATT

In that case the
python code doesn’t execute quickly,
It takes around 2 minutes until the telit module recharges the battery
to a voltage over 3.15V

Note that :

If there is no battery the python code executes normally

If the Voltage in the Li-ion battery is 3.15 or greater the python code executes normally

Is that behaviour normal?

3. Cosmin Buhu says:

VBATT is the main power supply and this dictates the behavior. More, the CAHRGER input, as per Hardware User Guide, must be limited to max 400 mA and is not designed to be used as the main power supply.

4. Our problem is if the battery is damaged then the telit doesn’t turn on even if it has main supply. So I thought we must have something wrong in our circuit

5. I assume you have the battery connected to VBATT and the 5V supply to CHARGE pin.

where is the main supply connected and what is the voltage?

6. You are correct, we have the battery to Vbatt and 4.2V to CHARGE pin.

Is it possible to connect 4.2 V and the battery to VBatt  ?

7. Hi Luis,

first of all 4.2V is a under CHARGER specs.

Charger input range is 5-7V, typical 5.5V.

In any case you cannot connect both 4.2V and battery to VBATT at the same time. You should switch between one and the other.

It is correct that the python script doesn’t start when the battery voltage is 3.0V. As you can see in the GE863-GPS docs, the minimum voltage is 3.22V. Below this voltage, the module is not powered on.