Solar performance.doc

23 minutes ago, Daan Meyer said:

Solar performance.doc 55.5 kB · 1 download

It's normal for panels to underperform under hot conditions, also experienced it with my system yesterday going from generating 1.2kw down to 200w as temperatures went up and down. Extra panels will help and then you could end up with say about 3000w on each Mppt (total of 6000w in panels) and you'll generate more Pv. It seems from your current setup your panels are only running off one Mppt. In winter (when it's cooler), more panels will also definitely help as, if it's less cloudy, you'll generate more power from having more panels.

Edited December 31, 20232 yr by Moffat

@Daan Meyer Even just one more panel will help to get you within the normal operating range of the inverter, two will be better.

Your installer has the story a bit wrong. The incidence angle of the sun is likely much better in Summer, ie. higher, or the rays are closer to shining 90 degrees straight onto the panel compared to Winter when the sun is low.

Your main issue is that you have too few panels such that when the temperature starts to affect the panel output, you are automatically close to the shut-down Voltage of the inverter on top of it all.

It doesn't help either that you are likely using a 13A panel that's at the limit of this model inverter's input current.

14 minutes ago, GreenFields said:

@Daan Meyer Even just one more panel will help to get you within the normal operating range of the inverter, two will be better.

Your installer has the story a bit wrong. The incidence angle of the sun is likely much better in Summer, ie. higher, or the rays are closer to shining 90 degrees straight onto the panel compared to Winter when the sun is low.

Your main issue is that you have too few panels such that when the temperature starts to affect the panel output, you are automatically close to the shut-down Voltage of the inverter on top of it all.

It doesn't help either that you are likely using a 13A panel that's at the limit of this model inverter's input current.

@GreenFields if @Daan Meyer got 7 of these, what's your take (see attached screenshot), which would then be put on the other Mppt?

11 minutes ago, Moffat said:

@GreenFields if @Daan Meyer got 7 of these, what's your take (see attached screenshot), which would then be put on the other Mppt?

Personal 2c would be for no more than 6 of these per MPPT if you have a big battery bank, and for my own needs I'd use just 5. For 7 or 8 such panels I'd suggest to get the 8kW inverter.

My gut feeling on the 5kW inverter would've been to opt for 6 or 7x 460W panels per MPPTto get the Voltage closer to the nominal/midrange, and the power generated at 11A instead of clipping to 13A. If the costs make sense.

5 minutes ago, GreenFields said:

Personal 2c would be for no more than 6 of these per MPPT if you have a big battery bank, and for my own needs I'd use just 5. For 7 or 8 such panels I'd suggest to get the 8kW inverter.

My gut feeling on the 5kW inverter would've been to opt for 6 or 7x 460W panels per MPPTto get the Voltage closer to the nominal/midrange, and the power generated at 11A instead of clipping to 13A. If the costs make sense.

Only issue is the balancing act between these particular panels being available "on a promotion" vs 460w panels likely to be more expensive per watt. Thanks for your response.

37 minutes ago, Moffat said:

Only issue is the balancing act between these particular panels being available "on a promotion" vs 460w panels likely to be more expensive per watt. Thanks for your response.

Try checking panel prices st Herholdt's. From what I recall their panel prices per Watt are fairly consistent, and the lower Watt panels are well-priced too. I think it's the extra hardware that maybe makes a difference.

1 hour ago, Moffat said:

Only issue is the balancing act between these particular panels being available "on a promotion" vs 460w panels likely to be more expensive per watt. Thanks for your response.

6 X 525W-550W JA solar panels that have a 3V higher output would also make a nice match for a 5kW Sunsynk. 

If we look at the NOCT value of the 6 X 545W per MPPT you mentioned then normally there won't be clipping. Also the maximum Watts will drop to around 2500W per MPPT. 

3 hours ago, Daan Meyer said:

Solar performance.doc 55.5 kB · 7 downloads

The Trina 545w panels, manufactured by Vertex is not a good fit for any HV Mppt as the Imp is to high and the Vmp is to low. The Trina 545w panel has a Vmp of 31.4V and Imp of 17.37A.  Voc is 37.7V. 4S1P in your case would be 150v on the lower limit of the Mppt and voltage depreciation at 0.25% for every degree above 25°C. It would help to add 2 extra panels in series to overcome the startup voltage problem of the Mppt but you will still face clipping due to the higher current spec of the panels. These panels work great on Pwm charge controllers where you would connect 6 panels 2S3P 62V @52A.

12 minutes ago, TaliaB said:

The Trina 545w panels, manufactured by Vertex is not a good fit for any HV Mppt as the Imp is to high and the Vmp is to low. The Trina 545w panel has a Vmp of 31.4V and Imp of 17.37A.  Voc is 37.7V. 4S1P in your case would be 150v on the lower limit of the Mppt and voltage depreciation at 0.25% for every degree above 25°C. It would help to add 2 extra panels in series to overcome the startup voltage problem of the Mppt but you will still face clipping due to the higher current spec of the panels. These panels work great on Pwm charge controllers where you would connect 6 panels 2S3P 62V @52A.

Thanks and apologies, didn't check the spec of the precise panel, just went with typical values when I commented earlier. Message is even more so, with these panels, the Voltage is too low and current too high to be optimally used for this inverter.

1 hour ago, GreenFields said:

Thanks and apologies, didn't check the spec of the precise panel, just went with typical values when I commented earlier. Message is even more so, with these panels, the Voltage is too low and current too high to be optimally used for this inverter.

No problem @GreenFields what infuriates me is that the installer should know this, why install a system that could not be effiecient at the clients cost.😫 Do the planning properly and place your clients interest first.

3 hours ago, Scorp007 said:

6 X 525W-550W JA solar panels that have a 3V higher output would also make a nice match for a 5kW Sunsynk. 

If we look at the NOCT value of the 6 X 545W per MPPT you mentioned then normally there won't be clipping. Also the maximum Watts will drop to around 2500W per MPPT. 

@Scorp007 I concur with you there as well as share the disappointment shared by @TaliaB about the installer not advising the client correctly. Reason I was now mentioning the other 6-7 x 545w panels is because they're currently on promotion and this may help @GreenFields to salvage his installation and get some panel efficiency.