Questions to ask installer

[ButchDeal]

Yeah, I noticed that as well. I'm getting a 60 cell 300 watt module. It's the WSP-300M6. I assumed that the P400 can work on 60 cell modules and just showed the 72 and 96 cell modules since those are the ones more likely to be closer to 400 watts. But you know what they say about assuming. I'll ask my installer why they're planning on using the P400 instead of the P300.

Could they be using the P400 due to the 0-5% power tolerance that could potentially get clipped with the P300 optimizer? Just guessing.

If they were worried about clipping (unlikely) they would use the P320. The P400 is not really appropriate for a 60Cell module.

[solarix]

Ya, goto PVwatts and find out what the yield rate is for your area and compare it to the sales person's number then ask them how they can justify such high projections. Most outfits fudge these numbers in order to make the system look more cost effective. Your particular locality will produce (quite closely) a certain number of effective full hours of solar production. In my area you get about 1650 hours - so a 10kW system will produce 16,500kWh of energy each year.

[NYHeel]

For the OP, a rule of thumb in New Jersey is about 1200 kWh annually per kW of panels. Though that's probably a little conservative if you have a southern facing roof without much shade. So based on this rule a 10 kW system produces about 12,000 kWh per year. But you should check pvwatts for your specific situation.

[shet]

There are three things about black panels. One is the frame - black or silver. I wanted black. Then there is the spacing around the cells. Black or silver. I wanted black. Then there is the wires. Silver was ok for me. SunPower makes an all black for a ton more money.

Hello rsilvers, Do you know whether a "back-sheet" is the same as "spacing around cells" you mentioned? Also, which panel did you go for i.e. with black frame, black spacing and silver wire?

[solarix]

Sometimes the "back sheet" is a different color front and back. Might be black on front between the cells and white from the back...

[rsilvers]

Yes. Same thing. Back-sheet seems is the correct term.

Here is an LG that has black frame, black back sheet, and silver wires:

https://www.lgenergy.com.au/uploads/download_files/26eb3907c7562ae82cab8552611ddccb799345db.jpeg

[shet]

Yes. Same thing. Back-sheet seems is the correct term.

Thanks

[Lexnice]

How do I know which solar panel s and micro inverters, or single inverter, are best?
Which solar panels will perform best, have the least degradation of service, and will not need to be replaced for at least 25 years: Suniva OPT-285-60-4-1B0, LG 315, or SolarWorld SW 285 (or 290) Mono?
Also, there seems to be a differing of opinion amongst solar companies. Most swear that the best way to go is by using Enphase Micro Inverters. A few say that those fail very often and are "crap".So which is best: Enphase Micro Inverters or (1)*SolarEdge w/Optimizers Mod. SE5000 (or Mod. SE6000) 240V? By the way, who pays for labor when an installed solar system part fails?
Do both inverter systems work the same? It's not like the old Christmas Lights is it, where if one bulb went out, they all go out:in my case if one panel goes down......?
Thank you.

[shet]

If they were worried about clipping (unlikely) they would use the P320. The P400 is not really appropriate for a 60Cell module.

Why do you think a P400 is not appropriate for a 60 cell module ? Won't it dissipate heat better against a 300W panel as opposed to using P320? Isn't oversizing the optimizer better?

Also if in future 300W is upgraded to 380W panel, then having P400 beforehand might be good ?

[ButchDeal]

Why do you think a P400 is not appropriate for a 60 cell module ? Won't it dissipate heat better against a 300W panel as opposed to using P320? Isn't oversizing the optimizer better?

Also if in future 300W is upgraded to 380W panel, then having P400 beforehand might be good ?

The P400 has a lower max DC input current than the P320 (12.63A vs 13.75A) The P320 is better suited to high performance 60 cell modules.
oversizing is not better. Right sizing is.

[NYHeel]

My installer ended up using the P400 for my 310 watt panels. I did call solaredge to confirm that it would be fine and the guy I spoke to said it was no issue at all using the P400 with a 60 cell panel. I don't think it's any better but it doesn't appear to be worse.

[ButchDeal]

My installer ended up using the P400 for my 310 watt panels. I did call solaredge to confirm that it would be fine and the guy I spoke to said it was no issue at all using the P400 with a 60 cell panel. I don't think it's any better but it doesn't appear to be worse.

They will work with some 60 cell modules but they have different ranges. The P400 is geared to much higher voltages and lower amperages. in the moderate performance like 310w 60 cell not an issue, in higher performance 60 cell, it is getting outside the range.
There appear to be some installers that are just using P400s with all residential to be lazy, seems odd to me as it is not that hard to choose when to use the P400 (got more than 60 cells? yes. use the P400).

For example the SolarWorld SW300M has a short circuit current of 10.23, the P400 is only rated for 10.1 but the P320 is rated for 11. use the SW300M with a P400 and void the warranty on the P400 but fine with the P320

[NYHeel]

They will work with some 60 cell modules but they have different ranges. The P400 is geared to much higher voltages and lower amperages. in the moderate performance like 310w 60 cell not an issue, in higher performance 60 cell, it is getting outside the range.
There appear to be some installers that are just using P400s with all residential to be lazy, seems odd to me as it is not that hard to choose when to use the P400 (got more than 60 cells? yes. use the P400).

For example the SolarWorld SW300M has a short circuit current of 10.23, the P400 is only rated for 10.1 but the P320 is rated for 11. use the SW300M with a P400 and void the warranty on the P400 but fine with the P320

I hear what you're saying. I'm not sure why they use the P400s. Perhaps they have a bunch of them. My sales guy mentioned something about the P400 having a much higher max voltage and it can get quite cold where I am which increases voltage. However, I have the Winaico 310 watt panels and they have open circuit voltage of 40.3 (not sure if that's the right measurement). Considering the temperature coefficient of 0.29%/C, it would have to get 60 degrees colder than STC so it would have to be -35 degrees celsius to get a voltage of 48. Considering the record low in NJ is -37 celsius, I'm probably ok with the P320.

The good news is that the short circuit current at STC is 10.1 amps so I should be just ok with the P400.

[ButchDeal]

I hear what you're saying. I'm not sure why they use the P400s. Perhaps they have a bunch of them. My sales guy mentioned something about the P400 having a much higher max voltage and it can get quite cold where I am which increases voltage. However, I have the Winaico 310 watt panels and they have open circuit voltage of 40.3 (not sure if that's the right measurement). Considering the temperature coefficient of 0.29%/C, it would have to get 60 degrees colder than STC so it would have to be -35 degrees celsius to get a voltage of 48. Considering the record low in NJ is -37 celsius, I'm probably ok with the P320.

The good news is that the short circuit current at STC is 10.1 amps so I should be just ok with the P400.

Well you have to look at all the limits. the voltage one is not that important here as you are well inside it.
but your Winaico 310 modules have a Short circuit current of 10.1 amp which is the limit for the P400. The P300 has a shortcircuit current of 10amp so not good there, but the P320 has a short circuit of 11amps...