Maximum Input Voltage question

[myusername134]

Solar arrays show their Maximum Input Voltage question, many around the 100v range, so this cannot be exceeded. Solar panels have an "open circuit voltage" (VoC) which is the amount of electricity they produce when there is no load, ie the batteries are fully charged. Example, your typical 100w panel has a 22.8v VoC and accounting for cold weather adding another 20% making it 27.36v VoC. This would mean I could not have more then 3 100w panels in series (82.08v) to not exceed 100v.

I could add more panels in series - parallel to increase the watts to not exceed 100v. With these 100w panels for example, they have: 4.91A Optimum Operating Current, 5.21A Short-Circuit Current (Isc), and 15A Max. Series Fuse Rating. What do these figures mean? Does this mean they produce 4.91A with a 15A fuse limit meaning I could have the 3 100w (300w) panels in series in a 3 way parallel making it 900w at 14.73A (3 x 4.91A)? What does this 5.21A Short-Circuit Current figure mean?

This is all new to me, trying to better understand.

 

[timselectric]

In series, voltage is added up and amperage stays the same.
In parallel, amperage is added up and voltage stays the same.
Wattage is always added together.
When configuring your panels to match your SCC (Solar Charge Controller). You first put panels in series strings to get the desired voltage. Then you put the strings in parallel to get the desired amperage.
VOC is a hard limit, to avoid damaging the SCC.
Short circuit current is the output of the panel when it is dead shorted.
Use the optimum operating current for calculations.

 

[myusername134]

One other question: Many panels typically have 12 AWG cabling, this has a max amperage of 25A. If you put panels in parallel it will increase the amperage. Is this increased amperage run through all the panels in parallel or only experienced down channel example at the end connector pieces that then connect to the solar charger array? I suppose end connector pieces for connecting multiple panels in parallel would have a thicker wire, if this increased amperage runs through all panels, and not just the end connector pieces it will cause a fire if exceeding 25A.

 

[timselectric]

The combined amperage is only after the parallel connection.

 

[740GLE]

This is why when multiple panels or strings are paralleled, you could run out of current and MC4 can carry and a combiner box is a handy solution.