Cloning: Homestead expansion 4400W 48V
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Solar array
Panels + how they are wired (series x parallel)
Charge controller
MPPT/PWM between array and battery
Covered by your all-in-one: EG4 FlexBOSS18 includes MPPT charging.
Battery bank
Identical batteries in parallel
Inverter / all-in-one
DC to AC. All-in-one units include the charge controller.
Wire runs
One-way distances for wire and fuse sizing.
| Segment | Continuous | Run (one way) | Copper wire | V-drop | Fuse/breaker |
|---|---|---|---|---|---|
| Array to all-in-one PV input | 28.0A | 80 ft | 10 AWG | 2.68% | 35APV-rated (gPV) fuse or DC breaker |
| Battery bank to all-in-one | 195.3A | 5 ft | beyond 4/0 - see notes | - | 250AClass T |
Array to all-in-one PV input: show the math
Continuous current = 28A Design current = 28A x 1.25 (NEC continuous) = 35A Wire: 10 AWG copper (75C ampacity 35A); voltage drop 2.68% over 160ft round trip at 166.8V (target <= 3%) Fuse/breaker: 35A - two criteria, both required: carry the load: fuse >= design 35A -> next standard size = 35A protect the wire: fuse 35A <= 10 AWG ampacity 35A - OK construction: PV-rated (gPV) fuse or DC breaker
Battery bank to all-in-one: show the math
Continuous current = 195.3A Design current = 195.3A x 1.25 (NEC continuous) = 244.1A No single-conductor AWG in table satisfies ampacity + 3% drop Fuse/breaker: 250A - two criteria, both required: carry the load: fuse >= design 244.1A -> next standard size = 250A bank BMS continuous 280A >= fuse 250A: the bank can hold the fuse's rated load construction: Class T (interrupt rating matters on battery mains)
Mount the fuse close to the battery positive terminal - it protects the wire run, so the unprotected stub should be as short as possible.
Current or distance exceeds single 4/0 copper; parallel conductors or shorter runs required. Consult a professional.
Sized for 75C copper ampacity with the NEC 1.25 continuous factor and a 3% voltage-drop target. Round up when between sizes and verify against local code.
Balance of system - shopping list
| Item | Qty | For |
|---|---|---|
| 10 AWG copper wire | 1 | ~180 ft total (80 ft one way, round trip + slack) - Array to all-in-one PV input |
| 35A PV-rated (gPV) fuse or DC breaker | 1 | Array to all-in-one PV input |
| 250A Class T | 1 | Battery bank to all-in-one - include the matching fuse holder/block |
Derived from the wire and fuse guidance above. Wire lengths include round trip plus slack - verify against your actual layout, and verify ratings against local code. Buy fuses and wire from reputable electrical suppliers; marketplace listings for these items are a common source of counterfeit or mislabeled parts.
13 passing checks - expand to see the math
passBattery matches the 48V systemSystem voltage coherence
EG4 WallMount Indoor 48V 280Ah (51.2V nominal) is a 48V-class battery.
battery nominal 51.2V is in the 48V class == system 48V
passInverter matches the 48V systemSystem voltage coherence
EG4 FlexBOSS18 DC input is 48V-class.
inverter DC input 48V is in the 48V class == system 48V
passString Voc stays at 224.2V at -25C - cannot reach the 600V limit at any temperatureCold-temperature string voltage
4 x Canadian Solar HiKu6 CS6W-550MS 550W Mono PERC in series stays below the EG4 FlexBOSS18 max PV input voltage at your design low temperature. This string cannot reach 600V at any physically possible temperature.
Why this matters: Panel voltage rises as temperature falls. A string that measures fine in summer can exceed the controller's absolute maximum input voltage on the first cold clear morning, which can permanently destroy the controller - and at these DC power levels, failures can start fires. This is the mistake experienced builders catch most often in DIY parts lists.
Voc_string = Voc x N_series x (1 + tempCoeff/100 x (T_design - 25))
= 49.60V x 4 x (1 + (-0.26%/100) x (-25 - 25))
= 49.60V x 4 x 1.1300 = 224.2V
Controller max PV input: 600V
Crossover: string Voc reaches 600V at T = 25 + (600/198.4 - 1) x 100/-0.26 = -753.5C (below absolute zero - never reached)passString Vmp 166.8V has healthy margin over the 48V bankMPPT voltage margin
Clears the start floor cold and the hot-weather floor with sag included.
Vmp_string = 41.70V x 4 = 166.8V Start floor = V_batt + 5V = 48 + 5 = 53V Hot Vmp (~11% sag) = 166.8V x 0.89 = 148.5V vs hot floor 56V
passArray short-circuit current 28.00A is within the 62A limitArray current vs controller input limit
Within the EG4 FlexBOSS18 published max PV short-circuit current.
Isc_array = 14.00A x 2 parallel = 28.00A Controller max PV short-circuit current: 31A x 2 MPPT trackers (assumes strings split evenly across inputs) = 62A (manufacturer-specified, compared directly)
passController can pass the array's full output (85.9A of 208A rated)Array size vs controller charge output
No clipping at rated conditions.
Array = 550W x 8 panels = 4400W Potential charge current = 4400W / 51.2V = 85.9A Controller rated charge current: 208A
passArray 4400W is within the controller's 18000W rating at 48VMax array wattage for battery voltage
Within the published maximum array wattage.
Array = 550W x 8 panels = 4400W Controller max array wattage at 48V: 18000W
passEG4 FlexBOSS18 supports LiFePO4 chargingBattery chemistry support
Controller has a lithium profile or user-adjustable charge voltages.
battery chemistry = lifepo4; controller lifepo4_profile = true
passEG4 FlexBOSS18 charger supports LiFePO4Battery chemistry support
Inverter/charger has a lithium charge profile.
battery chemistry = lifepo4; inverter charger lifepo4_profile = true
passBank BMS limit 280A comfortably covers the inverter's 195.3A drawInverter draw vs battery BMS limit
Healthy headroom at full inverter load.
Inverter draw = 10000W / 51.2V = 195.3A Bank BMS limit = 140A x 2 batteries = 280A Headroom band starts at 80% of limit = 224A
passBank BMS peak 600A covers the inverter's 390.6A surgeInverter surge vs battery peak limit
Surge loads within the bank's published peak rating.
Surge draw = 20000W / 51.2V = 390.6A Bank BMS peak = 300A x 2 batteries = 600A
passCharge current 208A is within the bank's 280A capacityCharge current vs bank capacity
Charge rate within limits.
Controller rated charge = 208A Bank max charge = manufacturer max charge 140A x 2 = 280A
passClosed-loop comms available via eg4Closed-loop battery communications
The inverter can read state of charge and limits directly from the battery BMS. Enable closed-loop per both manuals.
inverter speaks [eg4, generic-can, rs485]; battery speaks [eg4, generic-can, rs485]; overlap [eg4, generic-can, rs485]
1 check not run (missing published specs)
not checkedNot checkedBattery parallel count
EG4 WallMount Indoor 48V 280Ah does not publish a max parallel count in our data. Verify with the manufacturer before paralleling 2 units.
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