I just purchased a Sol Ark 15k, a pallet (33) of Canadian Solar 445W Bifacial Solar Panel | CS3W-445MB-AG, and a 6 pack of the EG4-LL Lithium Batteries Kit | (48v 100Ah) with the enclosure and bus work. This is for an off grid cabin roughly 12 x 20 with a loft. I am also looking at a Sinclair ground mount.
I input the solar panel parameters into the Sol Ark sizing tool and it recommends 30 panels total. The Sol Ark 15k has 3 MMPTs so I was thinking for each MMPT two parallel strings of 5 in series. The math seems to work with 250VOC (Sol ark states 400VOC is max) and roughly 28 Amps max (max with bifacial gain) per each MMPT. The max the Sol Ark can us is 26 Amps but they say it will auto limit Amps on the rare chance the bifacial panels can get that high in Amps.
I am a mechanical engineer with basic electrical training and understanding. I have worked a lot with power plant high voltage and basic home wiring. I know I need some help on the layout and I am looking for any thoughts - good, bad, crazy, etc.
My plan is a Sinclair ground mount with the 30 solar panels. The ground mount is roughly 90 feet from the cabin. I am planning to install a tornado shelter (90% underground) right next to the cabin to use for the battery and inverter storage area. I am hoping it will stay cooler in the summer and above freezing in the winter. Location is southern Oklahoma. From the tornado shelter then the AC output from the Sol Ark would run a few feet to the breaker panel in the cabin.
If the 3 sets of 5s2p is a good idea then I was guessing 8 AWG wire (6 total, 3 pos, 3 neg). The MMPTs on the Sol Ark are limited to roughly that amount of Watts each. Not sure if the voltage drop calculator is factoring both directions but I think that would put the loss at less than 2%?
If the Sol Ark has breakers at the MMPT inputs do I still need or is there an advantage to more protection from a combiner box at the ground mount location? Given the wattage limitations per MMPT at the Sol Ark I am guessing I would need 3 separate outputs and 6 inputs. I know I still need to address grounding from panels to earth ground but I was going to tackle that later.
Another question I have and I am guessing others have the same question as I have noticed a couple of folks mention combining the EG4 battery 6 packs (5kW per battery) with Sol Arks - The Sol Ark 15k has two sets of positive and negative terminals to connect the batteries. The max Amp draw from the batteries can exceed the capacity from only one of the pos/neg terminal sets so I will need to split the output from the batteries or run two sets of leads between the battery bus bars and the Sol Ark. Looking at the Amp capacity it looks like you could go with a single set of 4/0 AWG leads from the battery bus bars to a split of some type to the Sol Ark or you could run two sets of 2/0 AWG leads between the Sol Ark and the battery pack. I thought the 2 sets of 2/0 AWG leads might allow for more even draw from batteries if the leads were attached at opposite ends of the bus bars (if that is even possible). I have not picked up the equipment yet so I don't know the bus bar configuration.
This also leads to another question and that is whether I need to have another fuse somewhere in the circuit between the battery pack and the Sol Ark? The Sol Ark wiring diagrams don't show one but if I have to use another set of bus bars to split the battery cables somewhere I thought that might be an opportunity to introduce a fuse to the circuit if needed.
Any feedback would be much appreciated. I know this configuration is simple compared to what most folks are doing but it has been a real technical journey for me. Roof vs ground mount, rapid shutdown (avoided with ground mount), tornado shelter idea for battery and inverter storage, etc. I will share a lot of pictures once I get started.
Thanks
I input the solar panel parameters into the Sol Ark sizing tool and it recommends 30 panels total. The Sol Ark 15k has 3 MMPTs so I was thinking for each MMPT two parallel strings of 5 in series. The math seems to work with 250VOC (Sol ark states 400VOC is max) and roughly 28 Amps max (max with bifacial gain) per each MMPT. The max the Sol Ark can us is 26 Amps but they say it will auto limit Amps on the rare chance the bifacial panels can get that high in Amps.
I am a mechanical engineer with basic electrical training and understanding. I have worked a lot with power plant high voltage and basic home wiring. I know I need some help on the layout and I am looking for any thoughts - good, bad, crazy, etc.
My plan is a Sinclair ground mount with the 30 solar panels. The ground mount is roughly 90 feet from the cabin. I am planning to install a tornado shelter (90% underground) right next to the cabin to use for the battery and inverter storage area. I am hoping it will stay cooler in the summer and above freezing in the winter. Location is southern Oklahoma. From the tornado shelter then the AC output from the Sol Ark would run a few feet to the breaker panel in the cabin.
If the 3 sets of 5s2p is a good idea then I was guessing 8 AWG wire (6 total, 3 pos, 3 neg). The MMPTs on the Sol Ark are limited to roughly that amount of Watts each. Not sure if the voltage drop calculator is factoring both directions but I think that would put the loss at less than 2%?
If the Sol Ark has breakers at the MMPT inputs do I still need or is there an advantage to more protection from a combiner box at the ground mount location? Given the wattage limitations per MMPT at the Sol Ark I am guessing I would need 3 separate outputs and 6 inputs. I know I still need to address grounding from panels to earth ground but I was going to tackle that later.
Another question I have and I am guessing others have the same question as I have noticed a couple of folks mention combining the EG4 battery 6 packs (5kW per battery) with Sol Arks - The Sol Ark 15k has two sets of positive and negative terminals to connect the batteries. The max Amp draw from the batteries can exceed the capacity from only one of the pos/neg terminal sets so I will need to split the output from the batteries or run two sets of leads between the battery bus bars and the Sol Ark. Looking at the Amp capacity it looks like you could go with a single set of 4/0 AWG leads from the battery bus bars to a split of some type to the Sol Ark or you could run two sets of 2/0 AWG leads between the Sol Ark and the battery pack. I thought the 2 sets of 2/0 AWG leads might allow for more even draw from batteries if the leads were attached at opposite ends of the bus bars (if that is even possible). I have not picked up the equipment yet so I don't know the bus bar configuration.
This also leads to another question and that is whether I need to have another fuse somewhere in the circuit between the battery pack and the Sol Ark? The Sol Ark wiring diagrams don't show one but if I have to use another set of bus bars to split the battery cables somewhere I thought that might be an opportunity to introduce a fuse to the circuit if needed.
Any feedback would be much appreciated. I know this configuration is simple compared to what most folks are doing but it has been a real technical journey for me. Roof vs ground mount, rapid shutdown (avoided with ground mount), tornado shelter idea for battery and inverter storage, etc. I will share a lot of pictures once I get started.
Thanks