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Time to add Panels to 2 X 6000XP

BrianVeg

Solar Enthusiast
Joined
Sep 19, 2023
Messages
95
Location
Michigan
I’ve currently implemented a battery backup system using 2 X 6000XP’s and 4 X Ruixu Batteries. See this thread if you’re interested in what I did.


Now it’s time to add my panels. The 6000XP’s have the following specs/limits that I am using in my planning:

  • Max temperature adjusted VoC of 480 Volts
  • Optimal operating voltage of 320 Volts
  • Optimal current of 17A with a max of 25A
  • Max wattage per MPPT is 4,000 watts
I’ve got limited space for a ground mount so I’m looking at 16 panels, possibly up to 24 panels.

I’ve been looking at using the attached BlueSun panels in 2 strings of 8s (one per inverter) or 3 strings of 8s.

Specs for these panels are:

Wattage - 460watts
VOC - 50.8 volts
ISC - 11.5 amps
low temp coefficient -0.26%
Impp -10.86 amps
Vmpp - 42.4 volts


If my calculations are correct. That should give me per string:
  • Temperature adjusted max VoC of ~450V
  • Operating voltage of ~340V
  • Assuming a nominal bifacial gain of 10% the operating current should be ~12amps
  • Optimal wattage of ~ 4080 watts
Which will give me across 2 strings ~8000 watts.

If I do 24 panels I was going to just add one more string to one of the 6000XP’s which will give me 12kW.

Does this make sense? Am I missing anything?

Thanx!!!
 

Attachments

  • BSM460M-72HBDspec.pdf
    1.1 MB · Views: 7
Trying to decide between these two panels. They end up close with the BlueSun’s able to produce more wattage, but for a higher cost.

Does anyone have experience with either of these panels?

Is it worth the extra $684 to get nominally 1kW extra?

bluesun bsm460m-72hbdBoviet BVM6612M-450S-H-HC-BF-DG
number of panels (series) 88
Max Voltage 458447
Voltage at Vmpp339326
# Parellel Strings11
Total Current11.9511.07
Wattage at Vmpp40513609
2 Strings @ avg high temp
Total Wattage @ Vmpp81027218
Total # of Panels1616
Cost per panel$207$164.25
Total cost$3,312$2,628
cost per watt (my calcs)$0.41$0.36
 

Attachments

  • Boviet Solar_8. Vega Series_Mono_Bifacial_Utility_Double Glass_052322 - BVM6612M-440-450S-H-HC...pdf
    485.9 KB · Views: 2
  • BSM460M-72HBDspec.pdf
    1.1 MB · Views: 0
The one thing you need to realize is that you will almost NEVER get full power from a panel.
Bifacial boost does help some in some conditions, but you will not get 8,102 watts in almost any situation.
 
The one thing you need to realize is that you will almost NEVER get full power from a panel.
Bifacial boost does help some in some conditions, but you will not get 8,102 watts in almost any situation.
Yeah that's a good thing to be sure you are aware of. For example, I have an array that has a total rated theoretical output of 5730 watts, but in full sun I pretty consistently see 4800 watts when the panels are hot in the sun - or a bit more than 5000 watts when they are colder in the winter. It's actually only on partly cloudy days with the "cloud edge" effect that I see the full theoretical output (sometimes actually a bit more like ~6000 watts) for parts of the day when the sun is breaking through the clouds.
 
Thanx @wdwtx2.0 and @AZ Solar Junkie, appreciate the input.

Let me rephrase my question a bit.
  1. Does anyone experience with either panel and does the panel brand really make a difference?
  2. Is it worth an $684 to get panels that have the potential to produce more?
Thanx
 
Thanx @wdwtx2.0 and @AZ Solar Junkie, appreciate the input.

Let me rephrase my question a bit.
  1. Does anyone experience with either panel and does the panel brand really make a difference?
  2. Is it worth an $684 to get panels that have the potential to produce more?
Thanx
Here are my thoughts/opinions:

Re: #1 - In my opinion, it's really all about the specs more than the brand of a panel. It's worth digging a little deeper than just the watts/volts/amperage numbers and looking at least at the thermal data - like how much the panel voltage goes down with increasing temperatures (at least this is important to me here in Arizona ;))

Re: #2 - it really depends on your particular situation and if there would really be an ROI in a reasonable time that makes it worth it. If all it's mostly going to mean is that your battery bank gets fully charged up slightly earlier in the day and it isn't going to reduce your electric grid usage, I don't think it would be worth it very much. On the other hand, if you were actually going to be using that extra array energy to offset your grid usage on a daily basis, then if might make more sense. Say on average an extra 6kwh times your electricity rate might add up to saving more than the original cost difference in the long term. If I read your original post correctly, it sounds like you are planning primarily to use your system for grid backup and not using much if any of the solar output to offset your grid usage. If that is the case, then I don't think it would be that valuable to add just 1kw to your array output for additional cost. Or maybe it would be if you consider you would be bringing in an extra ~6kwh or so of energy from your panels during a grid down situation, so you'll have that much more energy on a daily basis to be able to use until the grid comes back. It really comes down to your goals and how you plan to use your system, etc.
 
Are you getting a full pallet? If not then biasing towards what is stocked locally can be a good idea

16 is a partial pallet. Full is in the mid 20s. I believe 16 is enough to be shipped somewhat safely edge stacked on a pallet.
 
Let me rephrase my question a bit.
  1. Does anyone experience with either panel and does the panel brand really make a difference?
  2. Is it worth an $684 to get panels that have the potential to produce more?
Thanx
I have 2ea. 16 panel arrays of the Blue Sun 460W bifacials, and a 4 panel array for my PV direct mini split..
I got them because they were around the size I want, and they were in stock.
I have no complaints with them, they are working as expected.
 
if you were actually going to be using that extra array energy to offset your grid usage on a daily basis, then if might make more sense
@AZ Solar Junkie Actually that is what I’m going to do. Battery backup was Phase 1, adding solar to reduce reliance on grid is Phase 2.

it's really all about the specs
Thanx for this.

I got them because they were around the size I want, and they were in stock.

@wdwtx2.0 That’s kind of what I’m looking at, specifically size = voltage.
 
Get it. For me getting voltage where i wanted it was what was driving my decision. I was looking at Vmp specs to figure out which panels to get.
In that case look for the cell count and understand the different increments of cell counts / how to spider sense half cut vs full cut without looking at the spec sheet
 
I ended up ordering Qty 16 of the BlueSun panels earlier in this thread. I am purchasing a Ready Rack System from APA Solar.

Pretty excited to get this going.

The diagram below provides a picture of my current working design.

I have a couple of questions on the PV circuit.

  • Do I need the Circuit Breakers at the rack - they are the only OCPD in the circuit. My string are 8S
  • After my PV enters the house - can I run the PV wire in same wireways as the rest of my inverter circuitry including AC-IN and Out and Battery connections? The PV Wire will be THWN

1714573222379.png
 
I ended up ordering Qty 16 of the BlueSun panels earlier in this thread. I am purchasing a Ready Rack System from APA Solar.

Pretty excited to get this going.

The diagram below provides a picture of my current working design.

I have a couple of questions on the PV circuit.

  • Do I need the Circuit Breakers at the rack - they are the only OCPD in the circuit. My string are 8S
  • After my PV enters the house - can I run the PV wire in same wireways as the rest of my inverter circuitry including AC-IN and Out and Battery connections? The PV Wire will be THWN

View attachment 212605
As far as I understand, the breakers for the array can be near the inverter, rather than needing to be by the array.

Re: running the AC and DC wires in the same wireways, I don't know about NEC rules around that, but personally I would avoid the potential for the AC lines to induce AC frequencies on your DC lines. I'm sure someone who knows more like @timselectric can clarify if that's a real concern or not.
 
There are some exceptions for solar DC sharing conduits. But it is pretty complicated and my personal decision is to separate completely.

I believe physical barriers in wireway might loophole you out too.

Or switch philosophy to ignore code.
 
The diagram below provides a picture of my current working design.
BTW your +/- colors are not necessarily code compliant (or helpful to installation) in the sense that you need to have some means of keeping the two circuits distinct. Having two sets of colors (legal for ungrounded DC) achieves that
 
I believe physical barriers in wireway might loophole you out too.
That's what I read in the code which drove me to ask the question. To achieve this will take some rework of my existing install.

The inspector for my battery backup verified that I could run DC and AC in the same wireway, but solar DC seemed different.

Or switch philosophy to ignore code.
Passed inspection on my inverters and batteries for battery backup - really want to do the same for the panels

Having two sets of colors (legal for ungrounded DC) achieves that
Ah - that actually makes sense - I was going to do two black wires and two red wires - Thanx for that
 
@zanydroid I just talked to my AHJ and he's good with two reds and two blacks as long as they are zip tied whenever they are in a box or otherwise "exposed". Different interpretations in different states I guess.

He also validated that solar DC circuits need to be separated from everything else.
 
@zanydroid I just talked to my AHJ and he's good with two reds and two blacks as long as they are zip tied whenever they are in a box or otherwise "exposed". Different interpretations in different states I guess.

He also validated that solar DC circuits need to be separated from everything else.
Yeah, that is fine for code, you will need to sort it out though for yourself by toning the pairs or something (or connecting the end together and testing for continuity). If you taped them together for a pull you might interfere with the pull or lose the indicator.

Or just buy 4 colors. You don’t have the problem some people here had, where there were so many circuits they ran out of colors.
 
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