Mid-size ranch 48V (EG4 server rack)
48V system, designed for a -25C (-13F) cold snap - saved 2026-07-04
Compatibility checks
warningBank peak current limit unpublished - surge headroom unverifiedInverter surge vs battery peak limit
The EG4 6000XP can surge to 12000W (234.4A at 51.2V). EG4 LifePower4 V2 48V 100Ah does not publish a BMS peak discharge rating, so we cannot verify motor-start surges will not trip the BMS.
surge 12000W / 51.2V = 234.4A; BMS peak limit unpublished
13 passing checks - expand to see the math
passBattery matches the 48V systemSystem voltage coherence
EG4 LifePower4 V2 48V 100Ah (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 6000XP DC input is 48V-class.
inverter DC input 48V is in the 48V class == system 48V
passString Voc stays at 168.1V at -25C - cannot reach the 480V limit at any temperatureCold-temperature string voltage
4 x Canadian Solar HiKu6 CS6R-410MS 410W Mono PERC in series stays below the EG4 6000XP max PV input voltage at your design low temperature. This string cannot reach 480V 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))
= 37.20V x 4 x (1 + (-0.26%/100) x (-25 - 25))
= 37.20V x 4 x 1.1300 = 168.1V
Controller max PV input: 480V
Crossover: string Voc reaches 480V at T = 25 + (480/148.8 - 1) x 100/-0.26 = -831.1C (below absolute zero - never reached)passString Vmp 124.8V has healthy margin over the 48V bankMPPT voltage margin
Clears the start floor cold and the hot-weather floor with sag included.
Vmp_string = 31.20V x 4 = 124.8V Start floor = V_batt + 5V = 48 + 5 = 53V Hot Vmp (~11% sag) = 124.8V x 0.89 = 111.1V vs hot floor 56V
passArray short-circuit current 28.02A is within the 50A limitArray current vs controller input limit
Within the EG4 6000XP published max PV short-circuit current.
Isc_array = 14.01A x 2 parallel = 28.02A Controller max PV short-circuit current: 25A x 2 MPPT trackers (assumes strings split evenly across inputs) = 50A (manufacturer-specified, compared directly)
passController can pass the array's full output (64.1A of 125A rated)Array size vs controller charge output
No clipping at rated conditions.
Array = 410W x 8 panels = 3280W Potential charge current = 3280W / 51.2V = 64.1A Controller rated charge current: 125A
passArray 3280W is within the controller's 8000W rating at 48VMax array wattage for battery voltage
Within the published maximum array wattage.
Array = 410W x 8 panels = 3280W Controller max array wattage at 48V: 8000W
passEG4 6000XP supports LiFePO4 chargingBattery chemistry support
Controller has a lithium profile or user-adjustable charge voltages.
battery chemistry = lifepo4; controller lifepo4_profile = true
passEG4 6000XP charger supports LiFePO4Battery chemistry support
Inverter/charger has a lithium charge profile.
battery chemistry = lifepo4; inverter charger lifepo4_profile = true
passBank BMS limit 200A comfortably covers the inverter's 117.2A drawInverter draw vs battery BMS limit
Healthy headroom at full inverter load.
Inverter draw = 6000W / 51.2V = 117.2A Bank BMS limit = 100A x 2 batteries = 200A Headroom band starts at 80% of limit = 160A
pass2 in parallel is within the manufacturer limit of 64Battery parallel count
Supported parallel configuration.
2 in parallel vs manufacturer max 64
passCharge current 125A is within the bank's 200A capacityCharge current vs bank capacity
Charge rate within limits.
Controller rated charge = 125A Bank max charge = manufacturer max charge 100A x 2 = 200A
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, pylontech, generic-can, rs485]; battery speaks [eg4, victron, sol-ark, deye, growatt, generic-can, rs485]; overlap [eg4, generic-can, rs485]
Parts list
Wire and fuse guidance
| Segment | Continuous | Run (one way) | Copper wire | V-drop | Fuse/breaker |
|---|---|---|---|---|---|
| Array to all-in-one PV input | 28.0A | 40 ft | 8 AWG | 1.13% | 40APV-rated (gPV) fuse or DC breaker |
| Battery bank to all-in-one | 117.2A | 5 ft | 1/0 AWG | 0.22% | 150AClass T |
Array to all-in-one PV input: show the math
Continuous current = 28A Design current = 28A x 1.25 (NEC continuous) = 35A Wire: 8 AWG copper (75C ampacity 50A); voltage drop 1.13% over 80ft round trip at 124.8V (target <= 3%) Fuse/breaker: 40A - two criteria, both required: carry the load: fuse >= design 35A -> next standard size = 40A protect the wire: fuse 40A <= 8 AWG ampacity 50A - OK construction: PV-rated (gPV) fuse or DC breaker
Battery bank to all-in-one: show the math
Continuous current = 117.2A Design current = 117.2A x 1.25 (NEC continuous) = 146.5A Wire: 1/0 AWG copper (75C ampacity 150A); voltage drop 0.22% over 10ft round trip at 51.2V (target <= 3%) Fuse/breaker: 150A - two criteria, both required: carry the load: fuse >= design 146.5A -> next standard size = 150A protect the wire: fuse 150A <= 1/0 AWG ampacity 150A - OK bank BMS continuous 200A >= fuse 150A: 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 | ~90 ft total (40 ft one way, round trip + slack) - Array to all-in-one PV input |
| 40A PV-rated (gPV) fuse or DC breaker | 1 | Array to all-in-one PV input |
| 1/0 AWG copper wire | 1 | ~15 ft total (5 ft one way, round trip + slack) - Battery bank to all-in-one |
| 150A 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.