How many of these panels can I wire into this charge controller?

softdown

The 520 watt panels. Open circuit voltage 46.3. Max power current: 10.5

Hoping for two panels - laying flat on flat roof in cold climate. At 37 degree latitude. 

Reason for adding more panels: Need more power during hot summer months for refrigeration and freezers. 

Thinking four panels since I can get unused 520 watt panels for about $200/each.

softdown

Heliene panels. I never heard of them but that means almost nothing. They are BIG - 520 watts.

softdown

Plan is to simply lay the panels on this flat roof. Protected - to a degree. Easily have room for four XL panels.

softdown

Great experience with Outback FM80s. But overkill for a few auxiliary panels.

SumPower

Answer to your question in my economy is a big no!

2 In parallel it wont work because of over amperage.

2 In series in a cold climate, 

Not a good fit for thses panels as 46.3 (open circuit voltage) x 2 (panels) = 92.6.

92.6 x 1.1 (temp correction factor) = 101.86.

You don't say just how cold your low temps are, but this (1.1) is a safe adjustment just to say I wouldn't recommend it.

I have some panels at a cabin at the 36th parallel and the correction factor for my coldest temps is 1.17.

So 92.6 x 1.17 = 108.3 VOC corrected for cold temps there. That equals over voltage for any charge controller rated for 100 Volts max. Might work for a while, might work for the first sunrise at colder temps.

softdown

Suspected that. Single panel yields insufficient voltage for a 48v system. Unless the charge controller bumps it up. 

VOC is a factor of concern and the phenomenon at the back of my head. Studied that in 2014. It can hit -25F every several years. That is an early morning phenomenon as memory serves. 

Laying flat likely lowers the amp output - it is not ideal for output. I kind of thought that many controllers simply do not process any overage to their capabilities. Or perhaps they go interstellar instead. 

Seems a 100v charge controller is likely a bad choice for a 48v system.

So I can get panels of lower voltage for serial. Or higher voltage for parallel. 

Or I could get more capable controllers. 

Or I could wire it up and see what happens. The unexpected is not terribly unusual. Losing this charge controller is of little consequence.

softdown

Now I feel like a 150v charge controller is often needed for a 48v system. Foggy Memories.

Although it would be cheaper to find panels that should work with these two charge controllers.

softdown

These panels seem a decent fit with the above charge controller.

Serial output accounting for 1.25 VOC ~ 95 volts.
 ~ 18 amps.

Looks acceptable

softdown

Lower numbers this time. Odd. Used panels also. Slightly lower output now.