Synsynk 8.8Kw MPPT oversize question
I have read thru some of Keith’s post’s and his youtube video on the Synsynk Mppt : https://youtu.be/C1lNAuUhlnk
So it is my understanding that MPPT oversizing is catered for to an extent. The question is what is safe or reasonable. Most MPPT’s I have seen seem to specify at least 30%. Is there any rule of thumb for the Synsynk Inverters?
I currently have a Victron Inverter and MPPT using 320W panels and would like to explore going to the synsynk 8.8kw unit.
Currently my house position isn’t great as its heavily north east facing and roof inclination is 12 degrees. So my solar panels underperform heavily in the winter and even summer isn’t that great. Oversizing is key for me to get decent consistent solar throughput.
Since I have 21 x 320W panels I would like to reuse as much of them as is possible. The one MPPT will have 2 x 10 panel strings of panels. This would lead to a 123% oversize although I doubt, I would even get to 100% most days.
Questions is what to do with other MPPT. Most cost-effective solar panels is the 490W which is why I am looking at them. Their Impp is 12.9A and max MPPT amps is 11A so I cut the wattage of the panels to 418W and listed them as current limited panels in the below table. I don’t care about the wasted Amps as they will provide more sun hours over the course of the day. With 2 strings of 8 panels at current limited wattage they are 128.62% oversized(option1) and at 9 panels per string they are 144.69% oversized(option2).
So my question is to what level i can oversize ? I would prefer Option 2 and if not hopefully option 1 is acceptable. Any thoughts or advice would be appreciated?
Thanks Vassen for the input ,its appreciated.
To be honest not too concerned with the amp clipping on Panels. Due to the 5200W MPPT limit and reverse calculating volts and amps it will be very hard to even reach 11A. A example would be the MPPT running at say 300V for both strings and if I divide that by MPPT 5200W I get 17.33 Amps for the whole MPPT and thus 8.66Amps per string which isn’t even close to 11A never mind 12.9A.
The last 2-3 years power outages has increased significantly in my area and since mid Jan I have had 43 power outages ranging from 5min to 2 days and I am getting annoyed. With my existing solar array I make it work but have to compromise by not running appliances or the Geyser. This is why I would want to oversize the array to essentially take me off grid and convert Eskom to pre paid and have it as backup.
The oversizing is also very beneficial for Cloudy\rainy days where my current array really struggles. Thus I am looking at Option 2 which provides a really nice buffer at almost triple my current solar capacity. My understanding is similar to yours in that VOC is the golden measurement when I comes to MPPT as most can internally compensate to a certain level for wattage oversizing which is what this is. The average accepted MPPT wattage oversize seems to be 30% but I am hoping that my 44.69% will fall in that bracket. I am thus hoping one of the official support guys can give this a rubber stamp.