Hello,
I have a problem with a solar charger based on bq24650. The output voltage is designed to charge lead acid or lion batteries (see the switch on schematic).
For testing purposes the circuit is powered from power supply. Without load the circuit behaves as expected and on the output is also expected voltage. But if the load is connected, the output voltage is osciallating, see the picture bellow. What could be problem?
Thak you.
The real battery was connected. This issue seems to be "solved" by disabling TERM_EN feature. No sure why but if disabled, the battery is charged by stable current. Is there any reason why it behaves like this?
Anyway I have another issue with the same circuit. When connected to powersource, everything seems to be okay and the battery is charged by stable current. However if I connect the solar panel lighted up by sun, it does not charge the battery anymore. MPPT is set to approx 15V (nominal voltage of the solar panel, open circuit of the solar panel is ~21V).
This is measured on HIDRV pin of BQ
LODRV
BTST pin
HIDRV if the charger is connected to power supply and everything works well
Thanks for any answer.
Battery is 5Ah lead acid and wires are very short. The power of the solar panel is 15w. Measured voltage on the solar panel
on MPPSET pin
It looks like the controller is trying to regulate "soft" power from solar but if the voltage drops below certain level it stops working and try again after ~50ms.
I have founf out that some strange behaviour also occures if the circuit is connected to laboratory power source and without battery. This is measured on the output. The downpeaks every ~500ms.
I have only one PCB at this time as a prototype to proof of concept.
Now I have connected in on the laboratory power supply with 220R resistor as a load. This the output on the load (same as SRN):
VIN is constatn approx. 19V, no idea where to find pins IL and SW.
