SPV1040 for charging Li-io battery with solar panel and L6924D, will the timer be a problem?

Thread Starter


Joined Nov 17, 2018

I want to build a circuit that charges a battery pack with 10000mAh (4x 18650 Li-io batterie in parallel). I want to use the battery pack for providing power to an array of sensors that are controlled by a microprocessor, every 10 minutes the sensors are measrung and a GSM module sends data to a cloud. The rest of the time the system is in sleep mode.
The SPV1040 is really the only MPPT enabled controller that i found which is suitable for such a low powered application that is not unreasonably inefficient. But for charging Li-io batterys i need an additional charge controller. ST Microelectronics suggests the L6924D in one of their designs. So i wanted to use a solar panel with the following specification: 2V 0.4A at it's maximum power point and 2.4Voc 0.42Asc. If the L6924D starts a charge cycle it will also start a timer, this timer is programmable through a Capacitor. If the timer counts to 0 and the battery is not full a fault will be issued. So let's say it is a cloudy day and the L6924D starts a charge cycle, the 10000mAh will not be fully charged with the end of the timer, even if i set the timer to it's upper limit. Is there a way to bypass this? Maybe restarting the controller every day or so.