Hello guys,
I have a problem with deciding the right value of MPPT resistors. I am using BQ25504EVM module with all original components except for programmable resistors.
My solar array is made of 25 parallel-connected cells. I attached pictures that describe my way of finding an MPP of the solar array.
After finding MPP using the 1kW halogen light as a source and 10kOhm potentiometer as a load, I used SLURAQ1 excel sheet to find proper resistor values that would correspond the Umpp (1,061V).
I replaced the resistors with the mentioned values and using the same laboratory setup (1kW halogen - 45 cm's from the cells) I reached only 30 mA battery charging current which is sadly little if we take in consideration fact that Isc = 256 mA (Battery on a VBAT - Li-Ion 400mAh / 3.7V).
Do you know where might be a problem in my process?
Thank you for your reply.
