# Solar panel Voc

Open circuit voltage is high in solar panels,when feeding the same voltage to any charge controller IC which has Operating voltage range which is far less than the Open circuit voltage, will that voltage damages the Charge controller.

For Example. A6v Solar panel has VOC of 10v,Can this be applied to a charge controller whose Input operating voltage is 4.5v to 7v?

• Please format and punctuate your questions. Commented Apr 5, 2018 at 15:42
• Show work done, plan and Solar panel link Commented Apr 5, 2018 at 15:53

Generally yes for voltage breakdown limits.

However charger must be able to handle current supplied with unknown load. Therefore limit the current to practical value. (Rs = Voc/Isc) (battery ESR is very low)

Voltage drops with rising current to near maximum current <82% Voc depending on solar input down to ~72% Voc and solar panel chemistry. So your Rs can be smaller than above which would give maximum power at Rs=load.

Special SMPS is ideal with current regulation on both input and/or output with Vmax and optimum Vin to meet battery charge profile current and voltage.

MPPT regulators must find optimum input current and regulate output charge current and voltage. These are 4 functions to monitor and regulate (Vin, Iin, Iout, Vout) not necessarily done by 1 design or IC and depends on load. Load could be a very low ESR discharged battery or a battery management IC or anything else.

Smartest task is to learn these transfer functions for these 4 variables under all conditions day and night. This is essentially a photon excited current source with a voltage limit and thus source impedance is lowest at MPT. Z = ESR= ΔV/ΔI From Max Power Transfer Theorem This occurs when impedances are matched between any/all interfaces.

Undergrad Project Paper on this subject Note Figure 5 depends on PV panel Voc/Vmp = % Voc for MPT vs Solar input current. with examples from Wiki citations and algorithms. https://en.wikipedia.org/wiki/Maximum_power_point_tracking