Disable battery charging when full, enable when low?

Hello Everyone,

I am new to Particle electron, Kindly advice me to charge the LiPo battery using an external battery connected to Vin and ground. In order to keep the particle device on for two months, i would like to use external power source. I also use the PIR sensor and sleep mode which wakeup only when motion detected. Is there any method to disable the charging when battery is full and also I would like to charge the battery when battery voltage is low.

You can connect a larger LiPo battery to the Li+ pin and GND pin on the Electron to add a larger and longer lasting battery.

Then charging will automatically be handled by the PMIC chip which will start and stop charging automatically to keep the battery fully charged when there is power available to the VIN or USB inputs.

Thank you for your response @RWB. I can only connect a LiPo battery of 4.2 volt in the JST connector. Since the recommended voltage through the JST connector was 4.2 volt.

Yes, you can use any 3.7v LiPo battery, preferably with a battery protection PCB chip added to the battery.

So you could get a 10Ah 3.7v LiPo battery and connect it to the Li+ and GND pins instead of the JST connector. or you could put a JST connector on the larger battery also and keep using the battery port the same as with the included battery.

Ok, Thank you for your support @RWB

Hello @RWB,

Hope you are doing good,

I tried to recharge the LiPO battery from an external battery to keep the particle for atleast 2 months. when the LiPo’s voltage is 3.3 V, it will enable the charging and when it reaches 4.112V, it will disable charging, but no luck.
Kindly advice me
FuelGauge fuel;
value = fuel.getVCell();
percentage =fuel.getSoC();
PMIC power;
power.setInputVoltageLimit(4840); //Set the lowest input voltage to 4.84 volts.
power.setInputCurrentLimit(900); // default is 900mA
power.setMinimumSystemVoltage(3300);// default is 512mA matches my 3W panel
if (value == 4100)
else if (value <= 3400)

Can you draw a diagram of what you’re trying to do exactly so we can get a better idea of what you’re working with?

If you want to charge a LiPo battery connected to the JST connector or the Li+ pin then you need to feed Vin at least 5v or supply 5v to the USB connector.

Charging will not begin unless the input is above 4.9v.

We are currently using 7v battery connected to the VIN pin to charge the 3.7V battery connected to the JST connector. Actually, device uses both the batteries simultaneously and we noticed that the power wastage.

For example I used fully charged battery 4.2V (3.7)battery connected to the JST connector, and I use 7 v battery to the VIN pin. Since the JST battery is full so we couldnt see the red right, so it is not charging. But it is consuming the power from the secondary battery connected to the VIN,

when I check the battery level after 24 hours, the secondary battery voltage reduces below 4V. I would like the secondary battery to charge the battery in the JST connecter whenever the battery is low. It shouldnt consumes the battery when the primary battery is full. Kindly please advice me to sort this issue

Your current setup is not correct.

Just get a bigger AH LiPo battery. Trying to charge the main battery with a higher voltage external battery is not the way to go as you are already experiencing.

If you want to charge the main battery do it via a Solar Panel or other power source other than another battery.

The PMIC is a power path controller and it will use incoming power to charge the battery + feed power to the Electron. Once the battery is charged if there is still incoming power it will power the Electron from that until it’s gone, then it switches back to battery power to keep things running.

1 Like

If i use 10 Ah battery to charge the main battery, will it keep the device ON for more days.

Just use a larger battery and don’t try to charge it from another battery.