Have some off-grid cabin friends who are currently terribly low on solar panel wattage. They now have 4 new Rolls Surette 6v 445ah batteries wired for 24v system. Where they live in south central CO we get about 6 hours a day usable sunlight.... but they do have a bit of shading periodically during the day, but not too bad. They estimate average usage at 2672w/day with a max of 4102w/day. Their SCC is a Morning Star MPPT-45. I believe right now they only have about 550 watts of solar.
I was able to get them 6 x 265 watt panels from SanTan Solar. The problem is as these are used panels the label has been removed and the name on the junction box on the back gives me a dead end when trying to look them up.... seems to be a universal junction box not specific to the panel manufacturer. That said, I do have the panel specs.
Morning Star has a string calculator but they require the panel manufacturer to use it. I did search though their list of panels until I found one with specs nearly identical to these. When I ran the calculations using these 265w panels 2s3p their calculator indicated in the "blue." Which they indicate is on the high side but should not cause problems. I would love to do the math by hand but try as I might I just can't seem to get the numbers right.... or I just plain don't understand the numbers I get! Which is more likely! I would really appreciate someone checking this for me so I don't tell my friends it's fine to hook them up, then they burn up their SCC!!!
Here are the particulars and panel specs.
High temp: 93 (very rare! Usually mid 80's max)
Low Temp: -33 (also rare)
Panel specs:
72 cell, polycrystalline
Weather resistant. Certified for salt mist and ammonia resistance
Anti-Reflection surface treatment
Rated Power: 265W
Open circuit voltage (VOC): 44.2 V
Max power voltage (VMP): 35.33 V
Short circuit current (ISC): 8.20 A
Max power current: 7.50 A
Power Tolerance 0/+3%
Maximum system voltage: 600V (UL)
Fuse Rating: 15 A
IP65 Junction Box w/MC4 Compatible Connectors
Thank you so much!
I was able to get them 6 x 265 watt panels from SanTan Solar. The problem is as these are used panels the label has been removed and the name on the junction box on the back gives me a dead end when trying to look them up.... seems to be a universal junction box not specific to the panel manufacturer. That said, I do have the panel specs.
Morning Star has a string calculator but they require the panel manufacturer to use it. I did search though their list of panels until I found one with specs nearly identical to these. When I ran the calculations using these 265w panels 2s3p their calculator indicated in the "blue." Which they indicate is on the high side but should not cause problems. I would love to do the math by hand but try as I might I just can't seem to get the numbers right.... or I just plain don't understand the numbers I get! Which is more likely! I would really appreciate someone checking this for me so I don't tell my friends it's fine to hook them up, then they burn up their SCC!!!
Here are the particulars and panel specs.
High temp: 93 (very rare! Usually mid 80's max)
Low Temp: -33 (also rare)
Panel specs:
72 cell, polycrystalline
Weather resistant. Certified for salt mist and ammonia resistance
Anti-Reflection surface treatment
Rated Power: 265W
Open circuit voltage (VOC): 44.2 V
Max power voltage (VMP): 35.33 V
Short circuit current (ISC): 8.20 A
Max power current: 7.50 A
Power Tolerance 0/+3%
Maximum system voltage: 600V (UL)
Fuse Rating: 15 A
IP65 Junction Box w/MC4 Compatible Connectors
Thank you so much!