I have a storage system that can take 4000W 15A 450V DC limit. my current plan is to use 540W panels in a 4S2P setup with each array producing 2160W @ 198V and 4320W total. Reason I went with the 2P setup is that if a panel fail in the future, I can still get power from the other half. I can also run a 8S array and get 4320W at 396V. Is there any pros and cons on either setup. Thanks in advance.
Array Volts vs Watts
- Thread starter Wiz33
- Start date
MisterSandals
Participation Medalist
What is the MPPT (optimized range) of your SCC?
This would be pretty rare but its a good thought.
MichaelK
Solar Wizard
The voltage values are rather high, so are you confusing the Voc with the Vmp? The Voc is the voltage of the panels when NO current is flowing. The Vmp is the voltage when the panels power is actually being consumed.
That being said, once you are getting the voltage that high, power loss via the copper wiring is minscule to the point of not being measurable. I'd say the 2S is going to be just fine even if four in series is only ~160-170Vmp. But, I would agree with MS in that once a panel is up and running, a later failure would be very rare.
One plus for multiple strings is that you can exceed your controller's rated input by utilizing virtual tracking. That is, having multiple strings facing in multiple directions. Maybe one array facing SE while the other faces SW. Or three arrays, one facing East, one facing South, and one facing West. Since only one array is at full output at any given time, you don't exceed the controller's amp limit.
The real-world benefit of virtual tracking is you are placing a lower load on your battery across the length of the day. This is especially beneficial towards the late afternoon, where my power usage goes up, but my battery is not being drained because the West-facing array is making enough power for me to not drain the battery at all till after sunset.
That being said, once you are getting the voltage that high, power loss via the copper wiring is minscule to the point of not being measurable. I'd say the 2S is going to be just fine even if four in series is only ~160-170Vmp. But, I would agree with MS in that once a panel is up and running, a later failure would be very rare.
One plus for multiple strings is that you can exceed your controller's rated input by utilizing virtual tracking. That is, having multiple strings facing in multiple directions. Maybe one array facing SE while the other faces SW. Or three arrays, one facing East, one facing South, and one facing West. Since only one array is at full output at any given time, you don't exceed the controller's amp limit.
The real-world benefit of virtual tracking is you are placing a lower load on your battery across the length of the day. This is especially beneficial towards the late afternoon, where my power usage goes up, but my battery is not being drained because the West-facing array is making enough power for me to not drain the battery at all till after sunset.
This is the panel I am looking at, it shows
| Voltage (VOC) | 49.5 |
LONGi 540W Solar Panel 144 Cell LR5-72HBD-540M – A1SolarStore
LONGi 540W Solar Panel 144 Cell LR5-72HBD-540M at A1SolarStore
a1solarstore.com
MichaelK
Solar Wizard
Took a bit of digging to find out the actual Vmp? Don't understand why they have to make it so hard? Looking at the specs, your string of 5 panels would be putting out 41.65Vmp X 5panels = 208.25Vmp. Keep in mind that these are factory specs determined in a test chamber. You might see the day to day variation of ~20V or so, depending on the temp, time of day, and phase of the moon. But, at a voltage >200V, 12amps is not likely to see any significant voltage drop.
Thanks or the help.
Similar threads
