Hi, I'm new here, I have a background in electronics and some electrical work, but never with solar. After researching quite extensively over the last fortnight, I have a bit of an information overload and would like another set of eyes to look over my plan.
I'm aiming to off-grid a partial amount of my house, starting with my computer equipment. With the intention to extend that to other items in the house, such as TVs, aquarium heaters, fridge/freezer, lighting and so on at a much later date once I've expanded the initial setup that I'll list below. I don't plan on adding the hot water service, or air conditioning to this off-grid setup.
With my current usage for my computer equipment, I very rarely exceed 750W during gaming and idle mostly between 300W-500W throughout the rest of the day - the computer equipment is on 24/7 as it's a rackmount server setup. If I add in all of the other household appliances, the overall usage will be approximately 1.5kW depending on the time of day. I've opted to go with an AiO, specifically the Growatt SPF3500ES, seeing as I would not pull more than 2kW at the absolute most. I've purchased the Growatt inverter already and have it ready to go, as I didn't want to miss out on the good price at the time.
The panels I've sourced, but not bought, are 510W / 13.7a / 44.5VOC (specifically the Jinko JKM510N-60HL4-V) due to the good pricing in Australia. I have room to place 12 of these panels on the north facing side of the house.
I want to start with 6 panels in series to give ~3kW / ~267VOC which is within the range of 120VDC - 430VDC for the inverter and short of the max of 450VDC that I don't want to go anywhere near. I want to eventually go with 12 panels in a 6s2p configuration to give ~6kW capacity. Even though the SPF3500ES will only accept up to 4500w, I want to explore overpanelling due to the potential shade from trees at certain hours of the day, or cloudy days.
I won't have a battery initially, but plan on adding one 48v 50Ah or 48v 100Ah depending on budget, and then add more batteries as time goes on with the intention to get my equipment through the night comfortably without having to fall back to utility power constantly. I understand that not having a battery will continually share/flick between PV power and utility power throughout the day any time there is cloud cover or shade from a tree.
Depending on the feedback I receive from here, I'll purchase the Jinko panels in ~4 weeks from now, then the first battery ~6 weeks after the panels. I'll then assess the amount of power I'm generating and add either more panels, or more batteries going forward from that point.
I have the following on hand already:
1) Given that 12 panels in 6s2p will give ~27.4a. Based on my current understanding of electronics work, I believe the SPF3500ES will simply clip the incoming current to 22a with the remaining ~5a and 1.5kW PV power going to waste under perfect conditions. Am I correct in this thought process? or will I actually cause damage to the inverter?
2) In Australia, we don't have the requirement for DC isolator switches on roofs since 2021. Although it isn't required, it's still recommended to place one next to the inverter, which I would like to do. I have sourced, but not bought, a 500VDC 32a MCB from Schneider to cover the 27a coming in from the solar panels - will this be acceptable to be used as an isolation switch to "turn off" the solar panel connection to the inverter for maintenance etc? or should I look solely at DC isolation switches?
2a) In addition to the above, will I be fine with connecting both strings together in parallel and terminating them together at the MCB? or will I need a combiner box closer to the panels and run a single line to the MCB/DC isolator?
3) If, at a later date, I would like to add another 6 panels facing west to capture the afternoon/sunset, would this be viable to add into the existing strings in parallel without any real problems other than needing to up the amperage rating on the MCB to 50a to cover the ~41a potential from the solar panels? Would 41a from the solar panels be fine for the SPF3500ES in addition to question 1?
I believe that is all I can think of that I need clarification for currently, I'd appreciate any constructive feedback.
I'm aiming to off-grid a partial amount of my house, starting with my computer equipment. With the intention to extend that to other items in the house, such as TVs, aquarium heaters, fridge/freezer, lighting and so on at a much later date once I've expanded the initial setup that I'll list below. I don't plan on adding the hot water service, or air conditioning to this off-grid setup.
With my current usage for my computer equipment, I very rarely exceed 750W during gaming and idle mostly between 300W-500W throughout the rest of the day - the computer equipment is on 24/7 as it's a rackmount server setup. If I add in all of the other household appliances, the overall usage will be approximately 1.5kW depending on the time of day. I've opted to go with an AiO, specifically the Growatt SPF3500ES, seeing as I would not pull more than 2kW at the absolute most. I've purchased the Growatt inverter already and have it ready to go, as I didn't want to miss out on the good price at the time.
The panels I've sourced, but not bought, are 510W / 13.7a / 44.5VOC (specifically the Jinko JKM510N-60HL4-V) due to the good pricing in Australia. I have room to place 12 of these panels on the north facing side of the house.
I want to start with 6 panels in series to give ~3kW / ~267VOC which is within the range of 120VDC - 430VDC for the inverter and short of the max of 450VDC that I don't want to go anywhere near. I want to eventually go with 12 panels in a 6s2p configuration to give ~6kW capacity. Even though the SPF3500ES will only accept up to 4500w, I want to explore overpanelling due to the potential shade from trees at certain hours of the day, or cloudy days.
I won't have a battery initially, but plan on adding one 48v 50Ah or 48v 100Ah depending on budget, and then add more batteries as time goes on with the intention to get my equipment through the night comfortably without having to fall back to utility power constantly. I understand that not having a battery will continually share/flick between PV power and utility power throughout the day any time there is cloud cover or shade from a tree.
Depending on the feedback I receive from here, I'll purchase the Jinko panels in ~4 weeks from now, then the first battery ~6 weeks after the panels. I'll then assess the amount of power I'm generating and add either more panels, or more batteries going forward from that point.
I have the following on hand already:
- Growatt SPF3500ES - 4500W max PV input / 22a max current input / 450VDC max input
- Solar panel mounting hardware for the roof
- Cabling for the AC output circuits + circuit breakers
- 6mm² cabling for the solar panels
- 15a MC4 inline fuses for each string of solar panels
- MC4 crimper + connectors
1) Given that 12 panels in 6s2p will give ~27.4a. Based on my current understanding of electronics work, I believe the SPF3500ES will simply clip the incoming current to 22a with the remaining ~5a and 1.5kW PV power going to waste under perfect conditions. Am I correct in this thought process? or will I actually cause damage to the inverter?
2) In Australia, we don't have the requirement for DC isolator switches on roofs since 2021. Although it isn't required, it's still recommended to place one next to the inverter, which I would like to do. I have sourced, but not bought, a 500VDC 32a MCB from Schneider to cover the 27a coming in from the solar panels - will this be acceptable to be used as an isolation switch to "turn off" the solar panel connection to the inverter for maintenance etc? or should I look solely at DC isolation switches?
2a) In addition to the above, will I be fine with connecting both strings together in parallel and terminating them together at the MCB? or will I need a combiner box closer to the panels and run a single line to the MCB/DC isolator?
3) If, at a later date, I would like to add another 6 panels facing west to capture the afternoon/sunset, would this be viable to add into the existing strings in parallel without any real problems other than needing to up the amperage rating on the MCB to 50a to cover the ~41a potential from the solar panels? Would 41a from the solar panels be fine for the SPF3500ES in addition to question 1?
I believe that is all I can think of that I need clarification for currently, I'd appreciate any constructive feedback.
