Cloning: Well pump and outbuilding 24V
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Solar array
Panels + how they are wired (series x parallel)
Charge controller
MPPT/PWM between array and battery
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 charge controller | 17.7A | 60 ft | 8 AWG | 2.20% | 25APV-rated (gPV) fuse or DC breaker |
| Charge controller to battery bank | 60.0A | 10 ft | 4 AWG | 1.16% | 80AClass T |
| Battery bank to inverter | 156.3A | 6 ft | 3/0 AWG | 0.45% | 200AClass T |
Array to charge controller: show the math
Continuous current = 17.7A Design current = 17.7A x 1.25 (NEC continuous) = 22.1A Wire: 8 AWG copper (75C ampacity 50A); voltage drop 2.20% over 120ft round trip at 60.6V (target <= 3%) Fuse/breaker: 25A - two criteria, both required: carry the load: fuse >= design 22.1A -> next standard size = 25A protect the wire: fuse 25A <= 8 AWG ampacity 50A - OK construction: PV-rated (gPV) fuse or DC breaker
Charge controller to battery bank: show the math
Continuous current = 60A Design current = 60A x 1.25 (NEC continuous) = 75A Wire: 4 AWG copper (75C ampacity 85A); voltage drop 1.16% over 20ft round trip at 25.6V (target <= 3%) Fuse/breaker: 80A - two criteria, both required: carry the load: fuse >= design 75A -> next standard size = 80A protect the wire: fuse 80A <= 4 AWG ampacity 85A - OK bank BMS continuous 200A >= fuse 80A: the bank can hold the fuse's rated load construction: Class T (interrupt rating matters on battery mains)
Battery bank to inverter: show the math
Continuous current = 156.3A Design current = 156.3A x 1.25 (NEC continuous) = 195.3A Wire: 3/0 AWG copper (75C ampacity 200A); voltage drop 0.45% over 12ft round trip at 25.6V (target <= 3%) Fuse/breaker: 200A - two criteria, both required: carry the load: fuse >= design 195.3A -> next standard size = 200A protect the wire: fuse 200A <= 3/0 AWG ampacity 200A - OK bank BMS continuous 200A >= fuse 200A: 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.
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 |
|---|---|---|
| 8 AWG copper wire | 1 | ~135 ft total (60 ft one way, round trip + slack) - Array to charge controller |
| 25A PV-rated (gPV) fuse or DC breaker | 1 | Array to charge controller |
| 4 AWG copper wire | 1 | ~25 ft total (10 ft one way, round trip + slack) - Charge controller to battery bank |
| 80A Class T | 1 | Charge controller to battery bank - include the matching fuse holder/block |
| 3/0 AWG copper wire | 1 | ~15 ft total (6 ft one way, round trip + slack) - Battery bank to inverter |
| 200A Class T | 1 | Battery bank to inverter - 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.
Parts list
| Part | Qty | Est. price | Where to buy |
|---|---|---|---|
Generic (used, via Santan Solar) Used 250W 60-cell poly (Trina TSM-250PA05 class, representative) | 4 | $200 | |
EPEver Tracer 6415AN 60A MPPT controllerdatasheet | 1 | $250 | |
EG4 LifePower4 V2 24V 200Ah batterydatasheet | 1 | $1,199 | |
Giandel PS-4000QAR 4000W 24V Pure Sine Wave Inverter inverterdatasheet | 1 | $459 | |
| Estimated total | $2,108 |
warningBank peak current limit unpublished - surge headroom unverifiedInverter surge vs battery peak limit
The Giandel PS-4000QAR 4000W 24V Pure Sine Wave Inverter can surge to 8000W (312.5A at 25.6V). EG4 LifePower4 V2 24V 200Ah does not publish a BMS peak discharge rating, so we cannot verify motor-start surges will not trip the BMS.
surge 8000W / 25.6V = 312.5A; BMS peak limit unpublished
10 passing checks - expand to see the math
passBattery matches the 24V systemSystem voltage coherence
EG4 LifePower4 V2 24V 200Ah (25.6V nominal) is a 24V-class battery.
battery nominal 25.6V is in the 24V class == system 24V
passInverter matches the 24V systemSystem voltage coherence
Giandel PS-4000QAR 4000W 24V Pure Sine Wave Inverter DC input is 24V-class.
inverter DC input 24V is in the 24V class == system 24V
passCharge controller supports 24V banksSystem voltage coherence
EPEver Tracer 6415AN 60A MPPT supports 12/24/36/48V battery banks.
controller battery voltages [12, 24, 36, 48] include 24V
passString Voc stays at 87.6V at -25C - cannot reach the 150V limit at any temperatureCold-temperature string voltage
2 x Generic (used, via Santan Solar) Used 250W 60-cell poly (Trina TSM-250PA05 class, representative) in series stays below the EPEver Tracer 6415AN 60A MPPT max PV input voltage at your design low temperature. This string cannot reach 150V 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))
= 37.60V x 2 x (1 + (-0.33%/100) x (-25 - 25))
= 37.60V x 2 x 1.1650 = 87.6V
Controller max PV input: 150V
Crossover: string Voc reaches 150V at T = 25 + (150/75.2 - 1) x 100/-0.33 = -276.4C (below absolute zero - never reached)passString Vmp 60.6V has healthy margin over the 24V bankMPPT voltage margin
Clears the start floor cold and the hot-weather floor with sag included.
Vmp_string = 30.30V x 2 = 60.6V Start floor = V_batt + 5V = 24 + 5 = 29V Hot Vmp (~11% sag) = 60.6V x 0.89 = 53.9V vs hot floor 32V
passController can pass the array's full output (39.1A of 60A rated)Array size vs controller charge output
No clipping at rated conditions.
Array = 250W x 4 panels = 1000W Potential charge current = 1000W / 25.6V = 39.1A Controller rated charge current: 60A
passArray 1000W is within the controller's 1500W rating at 24VMax array wattage for battery voltage
Within the published maximum array wattage.
Array = 250W x 4 panels = 1000W Controller max array wattage at 24V: 1500W
passEPEver Tracer 6415AN 60A MPPT supports LiFePO4 chargingBattery chemistry support
Controller has a lithium profile or user-adjustable charge voltages.
battery chemistry = lifepo4; controller lifepo4_profile = true
passBank BMS limit 200A comfortably covers the inverter's 156.3A drawInverter draw vs battery BMS limit
Healthy headroom at full inverter load.
Inverter draw = 4000W / 25.6V = 156.3A Bank BMS limit = 200A x 1 batteries = 200A Headroom band starts at 80% of limit = 160A
passCharge current 60A is within the bank's 200A capacityCharge current vs bank capacity
Charge rate within limits.
Controller rated charge = 60A Bank max charge = manufacturer max charge 200A x 1 = 200A
1 check not run (missing published specs)
not checkedNot checkedArray current vs controller input limit
EPEver Tracer 6415AN 60A MPPT does not publish a PV input current limit in our data. MPPT controllers generally current-limit safely, but verify against the manual.
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