Cloning: RV 30A lithium upgrade 12V
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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 | 9.7A | 18 ft | 14 AWG | 1.30% | 15APV-rated (gPV) fuse or DC breaker |
| Charge controller to battery bank | 50.0A | 5 ft | 6 AWG | 1.54% | 70AClass T |
| Battery bank to inverter | 187.5A | 4 ft | beyond 4/0 - see notes | - | 250AClass T |
Array to charge controller: show the math
Continuous current = 9.7A Design current = 9.7A x 1.25 (NEC continuous) = 12.1A Wire: 14 AWG copper (75C ampacity 20A); voltage drop 1.30% over 36ft round trip at 67.8V (target <= 3%) Fuse/breaker: 15A - two criteria, both required: carry the load: fuse >= design 12.1A -> next standard size = 15A protect the wire: fuse 15A <= 14 AWG ampacity 20A - OK construction: PV-rated (gPV) fuse or DC breaker
Charge controller to battery bank: show the math
Continuous current = 50A Design current = 50A x 1.25 (NEC continuous) = 62.5A Wire: 6 AWG copper (75C ampacity 65A); voltage drop 1.54% over 10ft round trip at 12.8V (target <= 3%) Fuse/breaker: 70A - two criteria, both required: carry the load: fuse >= design 62.5A -> next standard size = 70A protect the wire: fuse 70A <= 6 AWG ampacity 65A - NOT satisfied, upsize the wire bank BMS continuous 400A >= fuse 70A: 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 = 187.5A Design current = 187.5A x 1.25 (NEC continuous) = 234.4A No single-conductor AWG in table satisfies ampacity + 3% drop Fuse/breaker: 250A - two criteria, both required: carry the load: fuse >= design 234.4A -> next standard size = 250A bank BMS continuous 400A >= 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 |
|---|---|---|
| 14 AWG copper wire | 1 | ~40 ft total (18 ft one way, round trip + slack) - Array to charge controller |
| 15A PV-rated (gPV) fuse or DC breaker | 1 | Array to charge controller |
| 6 AWG copper wire | 1 | ~15 ft total (5 ft one way, round trip + slack) - Charge controller to battery bank |
| 70A Class T | 1 | Charge controller to battery bank - include the matching fuse holder/block |
| 250A 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 |
|---|---|---|---|
Renogy 200W 12V Monocrystalline Solar Panel (RSP200D) | 3 | $570 | |
Victron Energy SmartSolar MPPT 100/50 controllerdatasheet | 1 | $300 | |
Victron Lithium Battery Smart 12.8V 330Ah batterydatasheet | 1 | $1,654 | |
Victron Energy MultiPlus-II 12/3000/120-50 2x120V inverterdatasheet | 1 | $1,088 | |
| Estimated total | $3,612 |
warningBank peak current limit unpublished - surge headroom unverifiedInverter surge vs battery peak limit
The Victron Energy MultiPlus-II 12/3000/120-50 2x120V can surge to 5500W (429.7A at 12.8V). Victron Lithium Battery Smart 12.8V 330Ah does not publish a BMS peak discharge rating, so we cannot verify motor-start surges will not trip the BMS.
surge 5500W / 12.8V = 429.7A; BMS peak limit unpublished
13 passing checks - expand to see the math
passBattery matches the 12V systemSystem voltage coherence
Victron Lithium Battery Smart 12.8V 330Ah (12.8V nominal) is a 12V-class battery.
battery nominal 12.8V is in the 12V class == system 12V
passInverter matches the 12V systemSystem voltage coherence
Victron Energy MultiPlus-II 12/3000/120-50 2x120V DC input is 12V-class.
inverter DC input 12V is in the 12V class == system 12V
passCharge controller supports 12V banksSystem voltage coherence
Victron Energy SmartSolar MPPT 100/50 supports 12/24V battery banks.
controller battery voltages [12, 24] include 12V
passString Voc stays at 88.9V at -10C - safe down to -58.8C (-73.8F)Cold-temperature string voltage
3 x Renogy 200W 12V Monocrystalline Solar Panel (RSP200D) in series stays below the Victron Energy SmartSolar MPPT 100/50 max PV input voltage at your design low temperature. The string would not reach the 100V limit until the temperature drops below -58.8C (-73.8F).
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))
= 27.00V x 3 x (1 + (-0.28%/100) x (-10 - 25))
= 27.00V x 3 x 1.0980 = 88.9V
Controller max PV input: 100V
Crossover: string Voc reaches 100V at T = 25 + (100/81 - 1) x 100/-0.28 = -58.8CpassString Vmp 67.8V has healthy margin over the 12V bankMPPT voltage margin
Clears the start floor cold and the hot-weather floor with sag included.
Vmp_string = 22.60V x 3 = 67.8V Start floor = V_batt + 5V = 12 + 5 = 17V Hot Vmp (~11% sag) = 67.8V x 0.89 = 60.3V vs hot floor 20V
passArray short-circuit current 9.66A is within the 60A limitArray current vs controller input limit
Within the Victron Energy SmartSolar MPPT 100/50 published max PV short-circuit current.
Isc_array = 9.66A x 1 parallel = 9.66A Controller max PV short-circuit current: 60A = 60A (manufacturer-specified, compared directly)
passController can pass the array's full output (46.9A of 50A rated)Array size vs controller charge output
No clipping at rated conditions.
Array = 200W x 3 panels = 600W Potential charge current = 600W / 12.8V = 46.9A Controller rated charge current: 50A
passArray 600W is within the controller's 700W rating at 12VMax array wattage for battery voltage
Within the published maximum array wattage.
Array = 200W x 3 panels = 600W Controller max array wattage at 12V: 700W
passVictron Energy SmartSolar MPPT 100/50 supports LiFePO4 chargingBattery chemistry support
Controller has a lithium profile or user-adjustable charge voltages.
battery chemistry = lifepo4; controller lifepo4_profile = true
passVictron Energy MultiPlus-II 12/3000/120-50 2x120V charger supports LiFePO4Battery chemistry support
Inverter/charger has a lithium charge profile.
battery chemistry = lifepo4; inverter charger lifepo4_profile = true
passBank BMS limit 400A comfortably covers the inverter's 187.5A drawInverter draw vs battery BMS limit
Healthy headroom at full inverter load.
Inverter draw = 2400W / 12.8V = 187.5A Bank BMS limit = 400A x 1 batteries = 400A Headroom band starts at 80% of limit = 320A
passCharge current 50A is within the bank's 400A capacityCharge current vs bank capacity
Charge rate within limits.
Controller rated charge = 50A Bank max charge = manufacturer max charge 400A x 1 = 400A
passClosed-loop comms available via victronClosed-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 [victron, pylontech, generic-can]; battery speaks [victron]; overlap [victron]
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