Van Electrical Calculator: Battery, Solar & Inverter Sizing
Tell the calculator what you’ll run in your van and for how long. It works out your daily energy use for summer and winter, sizes the battery bank, solar, alternator charger, shore charger and inverter, then builds the matching parts list. We used it to size FarOutVan #1’s system. It’s Part C of our DIY Van Electrical Guide, after Part A: Build Your Knowledge and Part B: How to Size Your System.
- Hover / tap any underlined wordUseful Tooltip! to reveal a useful tooltip.
- Start with our Electrical System Guide if you’re new to this!
12V DC
SUMMER |
WINTER |
|||||
|---|---|---|---|---|---|---|
| LOADName of the appliance. | CUR (A)AVERAGE CURRENT (in amps) drawn during operation. Find it on the product’s website, owner’s manual or spec sheet. |
HRS / DAY (h)How many HOURS per day this appliance is in operation. It’s a guesstimate. |
DAILY USAGE (Ah)CURRENT x HOURS |
CUR (A)AVERAGE CURRENT (in amps) drawn during operation. Find it on the product’s website, owner’s manual or spec sheet. |
HRS / DAY (h)How many HOURS per day this appliance is in operation. It’s a guesstimate. |
DAILY USAGE (Ah)CURRENT x HOURS |
| TOTAL | ||||||
120V AC
SUMMER |
WINTER |
|||||||
|---|---|---|---|---|---|---|---|---|
| LOADName of the appliance. | PWR (W)MAX POWER (in watts) of the load. Find it on the product’s website, owner’s manual or spec sheet. |
HRS / DAY (h)How many HOURS per day this appliance is in operation. It’s a guesstimate. |
DAILY USAGE (Ah)[(POWER/12) x HOURS] / 0.85 |
INVThis column is used to size the inverter. Check all the appliances that you plan on using simultaneously. Note that the biggest load is automatically selected by the calculator. | PWR (W)MAX POWER (in watts) of the load. Find it on the product’s website, owner’s manual or spec sheet. |
HRS / DAY (h)How many HOURS per day this appliance is in operation. It’s a guesstimate. |
DAILY USAGE (Ah)[(POWER/12) x HOURS] / 0.85 |
INVThis column is used to size the inverter. Check all the appliances that you plan on using simultaneously. Note that the biggest load is automatically selected by the calculator. |
| TOTAL | ||||||||
Battery Type
Your Type
WINTER columns added. The calculator compares summer vs winter and sizes for the worst case (highest usage).
Alternator
Size Your Main Components
Use the calculator above
Daily Energy Usage
? Ah
Battery Bank
? Ah
Solar Panels
? W
Solar Charger
?|?
Alternator Charge
? A
Shore Charger
? A
INVERTER
? W
Manual Mode Enabled.
Bold options = automagic values.
- DIAGNOSIS
- Does not compute. I need at least one load (12V DC or 120V AC) to size your system. Beep boop!
- Battery Bank: You need over 600Ah. Consider switching to Lithium instead.
- Battery Bank: You need over 600Ah and that’s over my capacity. Beep boop!
- Battery Bank: You need over 600Ah and that’s over my capacity. Beep boop!
- Battery Bank: Consider upgrading to a larger battery bank or adjusting your needs in 12V DC & 120V AC tables.
- SOLAR: The selected solar delivers too much current for this battery bank. Choose a smaller solar array or upgrade the battery bank.
- Alternator: Consider limiting the charger’s output current to 30A or upgrading the battery bank.
- Alternator: The selected charger is too big for your vehicle’s alternator (Small, Regular or Heavy-Duty/Dual). Choose a smaller alternator charger.
- Shore: The selected charger delivers too much current for your battery bank. Choose a smaller charger or upgrade the battery bank.
- Inverter: You need over 3000W and the wiring diagram doesn’t support that. Beep boop! Make sure to only check loads that’ll run simultaneously in the INV column of the 120V AC table.
- Inverter: Consider choosing a smaller inverter or upgrading your battery bank. Your autonomy is very short with the current selections.
- Inverter: The selected inverter draws too much current for this battery bank. Choose a smaller inverter or upgrade the battery bank.
- Inverter: Consider upgrading to a larger inverter or adjusting your needs in the 120V AC table.
- Heads up! We had to adjust the battery bank: no equivalent matched your new selection.
- SHORE CHARGER: not needed with inverter/charger.
Size Your Wires, Fuses & Breakers
+ Wire Lengths & Terminals Calculator
Appropriate wire gauge (AWG) varies with length & load and, therefore, is unique to each installation. Our wiring diagram automatically sizes the wire gauge, fuses & breakers to ensure that your own system is safe and performs as it should. Bonus: it also calculates all the wire lengths & terminals that you’ll need by type/gauge, which will make STEP 3 (customize your items list) super easy to complete. No other diagram does this!
- With the inputs you entered, we recommend downloading the HIGH-POWER wiring diagram.
Customize Your Items List
Fill these tables per your wiring diagram:
WIRES LENGTH (FT)
| AWG | 4/0 | 3/0 | 2/0 | 1/0 | 1 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| RED | |||||||||||||
| BLACK | |||||||||||||
| DUPLEX |
TERMINALS QUANTITY
| AWG | 4/0 | 3/0 | 2/0 | 1/0 | 1 | 2 | 4 | 6 | 8 | 10/12 | 14/16 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| #8 | |||||||||||
| #10 | |||||||||||
| 1/4 | |||||||||||
| 5/16 | |||||||||||
| 3/8 |
Cost EstimateIncludes everything on your Items List, except the 12V & 120V loads (appliances) and Tools. Prices on Amazon change frequently, so our estimate is subject to change.
$X,XXX USD
Items List
The list below defines your entire electrical system. Click on “ADD ITEMS TO AMAZON CART” section-by-section; make sure that all the items are valid (links to Amazon products sometimes change, please let us know if that’s the case!), and make sure all items are in stock at the moment.
Main
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | Terminal Fuse Block with Fuse 250A | Blue Sea (Catastrophic Fail Safe. Connects directly to battery post.) | 1 | Block + Fuse |
| 2 | System Switch | Blue Sea (Main System Switch) | 1 | View |
| 3 | Bus Bar (250A, 4 studs) | Blue Sea | 2 | View |
| 4 | Cover for Bus Bar (for 250A 4 studs) | Protect the Bus Bar | 2 | View |
| 5 | 40A Breaker/Switch, Surface Mount | Between Fuse Block and Bus Bar | 1 | View |
| 6 | Fuse Block (12 circuits) | Blue Sea (12V Distribution Panel) | 1 | View |
| 7 | Fuses Kit | Assorted Fuses (2A 3A 5A 7.5A 10A 15A 20A 25A 30A 35A) | 1 | View |
| 8 | Battery Monitor | Victron BMV-712 with Bluetooth | 1 | View |
Main
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | Class T Fuse, 300A | Blue Sea (Catastrophic Fail Safe) | 1 | View |
| 2 | Class T Fuse Block | Blue Sea (Holds the Class T Fuse) | 1 | View |
| 3 | System Switch | Blue Sea (Main System Switch) | 1 | View |
| 4 | Bus Bar (600A, 4 studs) | Blue Sea | 2 | View |
| 5 | Cover for Bus Bar (for 600A 4 studs) | Protect the Bus Bar | 2 | View |
| 6 | 40A Breaker/Switch, Surface Mount | Between Fuse Block and Bus Bar | 1 | View |
| 7 | Fuse Block (12 circuits) | Blue Sea (12V Distribution Panel) | 1 | View |
| 8 | Fuses Kit | Assorted Fuses (2A 3A 5A 7.5A 10A 15A 20A 25A 30A 35A) | 1 | View |
| 9 | Battery Monitor | Victron BMV-712 with Bluetooth | 1 | View |
Main
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | Class T Fuse, 400A | Blue Sea (Catastrophic Fail Safe) | 1 | View |
| 2 | Class T Fuse Block | Blue Sea (Holds the Class T Fuse) | 1 | View |
| 3 | System Switch | Blue Sea (Main System Switch) | 1 | View |
| 4 | Bus Bar (600A, 4 studs) | Blue Sea | 2 | View |
| 5 | Cover for Bus Bar (for 600A 4 studs) | Protect the Bus Bar | 2 | View |
| 6 | 40A Breaker/Switch, Surface Mount | Between Fuse Block and Bus Bar | 1 | View |
| 7 | Fuse Block (12 circuits) | Blue Sea (12V Distribution Panel) | 1 | View |
| 8 | Fuses Kit | Assorted Fuses (2A 3A 5A 7.5A 10A 15A 20A 25A 30A 35A) | 1 | View |
| 9 | Battery Monitor | Victron BMV-712 with Bluetooth | 1 | View |
Battery
Nothing to show here. You need to enter some 12V and/or 120V loads, or choose a battery bank if you are in manual mode.
Battery
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | AGM 100 Ah | Renogy AGM 100 Ah 12V | 1 | View |
Battery
| # | Item | Description | Quantity | View Link |
|---|---|---|---|---|
| 1 | AGM 200 Ah | Renogy AGM 200 Ah 12V | 1 | View |
Battery
Battery
Battery
Battery
Battery
| # | Item | Description | Quantity | Link |
|---|---|---|---|---|
| 1 | LiFePO4 105 Ah | Epoch LiFePO4 105 Ah 12V (Essential Series) | 1 | View |
Battery
| # | Item | Description | Quantity | Link |
|---|---|---|---|---|
| 1 | LiFePO4 300 Ah | Epoch LiFePO4 300 Ah 12V (Essential Series) | 1 | View |
Battery
| # | Item | Description | Quantity | Link |
|---|---|---|---|---|
| 1 | LiFePO4 300 Ah | Epoch LiFePO4 300 Ah 12V (Essential Series) | 1 | View |
Battery
| # | Item | Description | Quantity | Link |
|---|---|---|---|---|
| 1 | LiFePO4 460 Ah | Epoch LiFePO4 460 Ah 12V (Essential Series) | 1 | View |
Battery
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | LiFePO4 100 Ah | Renogy LiFePO4 100 Ah 12V | 1 | View |
Battery
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | LiFePO4 200 Ah | Renogy LiFePO4 200 Ah 12V | 1 | View |
Battery
Battery
Battery
Battery
Battery
Battery
Battery
Battery
Battery
| # | Item | Description | Quantity | Link |
|---|---|---|---|---|
| 1 | LiFePO4 300 Ah | Epoch LiFePO4 300 Ah 12V (Essential Series) | 1 | View |
Battery
| # | Item | Description | Quantity | Link |
|---|---|---|---|---|
| 1 | LiFePO4 460 Ah | Epoch LiFePO4 460 Ah 12V (Essential Series) | 1 | View |
Battery
Battery
Battery
Battery
Solar
Nothing to show here. You can add solar charging later if you change your mind, as our wiring diagram allows for future expansion!
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 100W Solar | Renogy 100W Mono Panel | 1 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 25A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 75|15 SmartSolar MPPT | 1 | View |
| 6 | 25A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 180W Solar | NewPowa 180W Mono Panel | 1 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 25A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 75|15 SmartSolar MPPT | 1 | View |
| 6 | 25A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 200W Solar | Renogy 100W Mono Panel | 2 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 25A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 75|15 SmartSolar MPPT | 1 | View |
| 6 | 25A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 300W Solar | Renogy 100W Mono Panel | 3 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 40A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 100|30 SmartSolar MPPT | 1 | View |
| 6 | 40A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Add Items To Amazon Cart*
*Item #5 (Victron MPPT) is sold by Vanlife Outfitters, so it isn’t in this Amazon cart.
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 360W Solar | NewPowa 180W Mono Panel | 2 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 40A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 100|30 SmartSolar MPPT | 1 | View |
| 6 | 40A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Add Items To Amazon Cart*
*Item #5 (Victron MPPT) is sold by Vanlife Outfitters, so it isn’t in this Amazon cart.
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 540W Solar | NewPowa 180W Mono Panel | 3 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 60A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 100|50 SmartSolar MPPT | 1 | View |
| 6 | 60A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Add Items To Amazon Cart*
*Item #5 (Victron MPPT) is sold by Vanlife Outfitters, so it isn’t in this Amazon cart.
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 720W Solar | NewPowa 180W Mono Panel | 4 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 70A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Victron 150|60 SmartSolar MPPT | 1 | View |
| 6 | 70A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 100W Solar | Renogy 100W Mono Panel | 1 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 30A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 20A MPPT | 1 | View |
| 6 | 30A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 180W Solar | NewPowa 180W Mono Panel | 1 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 30A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 20A MPPT | 1 | View |
| 6 | 30A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 200W Solar | Renogy 100W Mono Panel | 2 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 30A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 20A MPPT | 1 | View |
| 6 | 30A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 300W Solar | Renogy 100W Mono Panel | 3 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 40A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 30A MPPT | 1 | View |
| 6 | 40A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 360W Solar | NewPowa 180W Mono Panel | 2 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 40A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 30A MPPT | 1 | View |
| 6 | 40A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 540W Solar | NewPowa 180W Mono Panel | 3 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 70A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 60A MPPT | 1 | View |
| 6 | 70A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Solar
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 720W Solar | NewPowa 180W Mono Panel | 4 | View |
| 2 | Extension Cables, 8 AWG, 15 ft Red + 15 ft Black | With MC4 Connectors | 1 | View |
| 3 | Double Cable Entry Gland | For 8 AWG or 10 AWG Cable | 1 | View |
| 4 | 70A Breaker/Switch, Surface Mount | Between Panels and MPPT Charger | 1 | View |
| 5 | MPPT Solar Charger | Renogy Rover LI 60A MPPT | 1 | View |
| 6 | 70A Breaker/Switch, Surface Mount | Between MPPT Charger & Battery | 1 | View |
Alternator
Nothing to show here. You can add alternator charging later if you change your mind, as our wiring diagram allows for future expansion!
Alternator
Shore
Nothing to show here. You can add shore charging later if you change your mind, as our wiring diagram allows for future expansion!
Shore
Shore
Inverter
Nothing to show here. You can add an inverter later if you change your mind, as our wiring diagram allows for future expansion!
Inverter
Optional Items:
Inverter
Optional Items:
Inverter
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 2000W Inverter | Samlex NTX-2000-12 Pure Sine | 1 | View |
| 2 | Remote Control for Inverter | Included |
Optional Items:
Inverter
Optional Items:
Inverter
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 1500W Inverter | AIMS 1500W Pure Sine | 1 | View |
| 2 | Remote Control for Inverter | AIMS Remote ON/OFF (optional, no compatible remote on Amazon right now) | 1 | – |
| 3 | Terminal Fuse Block with Fuse 200A | Blue Sea (Connects directly on the Bus Bar. To protect inverter’s cable.) | 1 | Block + Fuse |
Optional Items:
Inverter
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 2000W Inverter | Renogy 2000W Pure Sine | 1 | View |
| 2 | Remote Control for Inverter | Included |
Optional Items:
Inverter/Charger
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 2000W Inverter/Charger | Victron Multiplus Compact 12|2000|80 | 1 | View |
| 2 | Remote Control for Inverter | Victron Digital Multi Control 200/200A GX | 1 | View |
| 3 | Class T Fuse, 300A | Blue Sea (To protect inverter’s cable) | 1 | View |
| 4 | Class T Fuse Block | Blue Sea (Holds the Class T Fuse) | 1 | View |
| 5 | 30A Shore Inlet | Park Power 30A Easy Lock RV Inlet | 1 | View |
| 6 | 30A AC Main | Breaker Between Power Inlet and Inverter/Charger | 1 | View |
| 7 | 120V AC Distribution Panel (4 Positions*) | Blue Sea Panel: AC Main + 4 Positions* | 1 | View |
| 8 | 10/3 AWG Triplex AC Marine Wire | Between power inlet & inverter/charger | 1 | View |
| 9 | 6/3 AWG Triplex AC Marine Wire | Between inverter/charger & AC distribution panel | 1 | View |
| 10 | 120V AC GFCI Outlet | GFCI, 15A | 1 | View |
| 11 | 14/3 AWG Triplex AC Marine Wire | To wire load that requires 15A or 10A breaker | 1 | View |
Optional Items:
| # | Optional Item | Description | View on Amazon |
|---|---|---|---|
| 1 | 50A Breaker (Double-Pole) | To upgrade 120V AC distribution panel to 50A instead of 30A | View |
| 2 | 20A Breaker | For load that requires 20A breaker (e.g. A/C) | View |
| 3 | 10A Breaker | For load that requires 10A breaker | View |
| 4 | 120V AC Distribution Panel (6 Positions*) | *The 6-position panel is sometimes cheaper, check it! | View |
| 5 | 12/3 AWG Triplex AC Marine Wire | To wire load that requires 20A breaker (e.g. A/C) | View |
Inverter/Charger
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 2000W Inverter/Charger | Victron Multiplus Compact 12|2000|80 | 1 | View |
| 2 | Remote Control for Inverter | Victron Digital Multi Control 200/200A GX | 1 | View |
| 3 | Class T Fuse, 300A | Blue Sea (To protect inverter’s cable) | 1 | View |
| 4 | Class T Fuse Block | Blue Sea (Holds the Class T Fuse) | 1 | View |
| 5 | 30A Shore Inlet | Park Power 30A Easy Lock RV Inlet | 1 | View |
| 6 | 30A AC Main | Breaker Between Power Inlet and Inverter/Charger | 1 | View |
| 7 | 120V AC Distribution Panel (4 Positions*) | Blue Sea Panel: AC Main + 4 Positions* | 1 | View |
| 8 | 10/3 AWG Triplex AC Marine Wire | Between power inlet & inverter/charger | 1 | View |
| 9 | 6/3 AWG Triplex AC Marine Wire | Between inverter/charger & AC distribution panel | 1 | View |
| 10 | 120V AC GFCI Outlet | GFCI, 15A | 1 | View |
| 11 | 14/3 AWG Triplex AC Marine Wire | To wire load that requires 15A or 10A breaker | 1 | View |
Optional Items:
| # | Optional Item | Description | View on Amazon |
|---|---|---|---|
| 1 | 50A Breaker (Double-Pole) | To upgrade 120V AC distribution panel to 50A instead of 30A | View |
| 2 | 20A Breaker | For load that requires 20A breaker (e.g. A/C) | View |
| 3 | 10A Breaker | For load that requires 10A breaker | View |
| 4 | 120V AC Distribution Panel (6 Positions*) | *The 6-position panel is sometimes cheaper, check it! | View |
| 5 | 12/3 AWG Triplex AC Marine Wire | To wire load that requires 20A breaker (e.g. A/C) | View |
Inverter/Charger
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 3000W Inverter/Charger | Victron Multiplus Compact 12|3000|120 | 1 | View |
| 2 | Remote Control for Inverter | Victron Digital Multi Control 200/200A GX | 1 | View |
| 3 | Class T Fuse, 400A | Blue Sea (To protect inverter’s cable) | 1 | View |
| 4 | Class T Fuse Block | Blue Sea (Holds the Class T Fuse) | 1 | View |
| 5 | 30A Shore Inlet | Park Power 30A Easy Lock RV Inlet | 1 | View |
| 6 | 30A AC Main | Breaker Between Power Inlet and Inverter/Charger | 1 | View |
| 7 | 120V AC Distribution Panel (4 Positions*) | Blue Sea Panel: AC Main + 4 Positions* | 1 | View |
| 8 | 10/3 AWG Triplex AC Marine Wire | Between power inlet & inverter/charger | 1 | View |
| 9 | 6/3 AWG Triplex AC Marine Wire | Between inverter/charger & AC distribution panel | 1 | View |
| 10 | 120V AC GFCI Outlet | GFCI, 15A | 1 | View |
| 11 | 14/3 AWG Triplex AC Marine Wire | To wire load that requires 15A or 10A breaker | 1 | View |
Optional Items:
| # | Optional Item | Description | View on Amazon |
|---|---|---|---|
| 1 | 50A Breaker (Double-Pole) | To upgrade 120V AC distribution panel to 50A instead of 30A | View |
| 2 | 20A Breaker | For load that requires 20A breaker (e.g. A/C) | View |
| 3 | 10A Breaker | For load that requires 10A breaker | View |
| 4 | 120V AC Distribution Panel (6 Positions*) | *The 6-position panel is sometimes cheaper, check it! | View |
| 5 | 12/3 AWG Triplex AC Marine Wire | To wire load that requires 20A breaker (e.g. A/C) | View |
Inverter/Charger
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | 3000W Inverter/Charger | Victron Multiplus Compact 12|3000|120 | 1 | View |
| 2 | Remote Control for Inverter | Victron Digital Multi Control 200/200A GX | 1 | View |
| 3 | Class T Fuse, 400A | Blue Sea (To protect inverter’s cable) | 1 | View |
| 4 | Class T Fuse Block | Blue Sea (Holds the Class T Fuse) | 1 | View |
| 5 | 30A Shore Inlet | Park Power 30A Easy Lock RV Inlet | 1 | View |
| 6 | 30A AC Main | Breaker Between Power Inlet and Inverter/Charger | 1 | View |
| 7 | 120V AC Distribution Panel (4 Positions*) | Blue Sea Panel: AC Main + 4 Positions* | 1 | View |
| 8 | 10/3 AWG Triplex AC Marine Wire | Between power inlet & inverter/charger | 1 | View |
| 9 | 6/3 AWG Triplex AC Marine Wire | Between inverter/charger & AC distribution panel | 1 | View |
| 10 | 120V AC GFCI Outlet | GFCI, 15A | 1 | View |
| 11 | 14/3 AWG Triplex AC Marine Wire | To wire load that requires 15A or 10A breaker | 1 | View |
Optional Items:
| # | Optional Item | Description | View on Amazon |
|---|---|---|---|
| 1 | 50A Breaker (Double-Pole) | To upgrade 120V AC distribution panel to 50A instead of 30A | View |
| 2 | 20A Breaker | For load that requires 20A breaker (e.g. A/C) | View |
| 3 | 10A Breaker | For load that requires 10A breaker | View |
| 4 | 120V AC Distribution Panel (6 Positions*) | *The 6-position panel is sometimes cheaper, check it! | View |
| 5 | 12/3 AWG Triplex AC Marine Wire | To wire load that requires 20A breaker (e.g. A/C) | View |
Wires
Nothing to show here. You need to fill the “Wires” table in the calculator above.
Terminals
Nothing to show here. You need to fill the “Terminals” table in the calculator above.
Hardware
| # | Item | Description | Quantity | View on Amazon |
|---|---|---|---|---|
| 1 | Heat Shrink Butt Connector, Ancor Marine | To connect to Loads (75 Pack Kit) | 1 | View |
| 2 | Heat Shrink Disconnect, 10-12 AWG Cable, 1/4″ Tab, Female |
To connect to certain loads (e.g. 12V sockets), to make “removable” connections (e.g. fridge, LEDs) and to connect cables of different gauges together (e.g. LED dimmer) (25 Pack) |
1 | View |
| 3 | Heat Shrink Disconnect, 10-12 AWG Cable, 1/4″ Tab, Male | 1 | View | |
| 4 | Heat Shrink Disconnect, 14-16 AWG Cable, 1/4″ Tab, Female | 1 | View | |
| 5 | Heat Shrink Disconnect, 14-16 AWG Cable, 1/4″ Tab, Male | 1 | View | |
| 6 | Heat Shrink Disconnect, 18-22 AWG Cable, 1/4″ Tab, Male | 1 | View | |
| 7 | 3M Scotchlok Quick Splice with Gel (14 AWG stranded) | We used that to parallel our LED lights (25 Pack) | 1 | View |
| 8 | Heat Shrink Tubing Kit (with adhesive) | To protect lugs after crimping | 1 | View |
| 9 | Split Loom Tubing, 3/8″ diameter 25 feet | To protect wire bundles | 1 | View |
| 10 | Split Loom Tubing, 1/2″ diameter 25 feet | To protect wire bundles | 1 | View |
| 11 | Split Loom Tubing, 3/4″ diameter 10 feet | To protect wire bundles | 1 | View |
| 12 | Nylon Cable Clamps Kit | To secure cable/split-loom to wood | 1 | View |
| 13 | Zip Tie Mount with Adhesive | To secure cable/split-loom to metal | 1 | View |
| 14 | Nylon Zip Ties Kit | To secure cable/split-loom | 1 | View |
| 15 | Rubber Grommet Kit | To protect wires from sharp edges (through metal holes) | 1 | View |
12V Loads
These are the appliances we used in FarOutVan #1:
| # | Item | Quantity | Buy Link | More Info |
|---|---|---|---|---|
| 1 | Maxxair 6200K Roof Fan | 1 | Amazon | Fan Installation |
| 2 | LED Ceiling Lights (Dimmable) | 3 | Amazon | |
| 3 | PWM Dimmer for LED Lights, 12V, Slider | 1 | Amazon | |
| 4 | Blue Sea 12V Socket | 4 | Amazon | Electrical System Guide |
| 5 | Shurflo Revolution Water Pump, 3 GPM | 1 | Amazon | |
| 6 | ON/OFF Switch for Water Pump | 1 | Amazon | |
| 7 | Webasto Air Top 2000 STC Gasoline Heater | 1 | Vanlife Outfitters | Webasto Installation |
| 8 | Propex HS2000 Propane Heater | 1 | Dealers | Propex Installation |
| 9 | Novakool R5810 Fridge, 12V only | 1 | Campervan-HQ | Fridge Guide |
| 10 | Sirocco II Gimbal Fan, 12V | 1 | Amazon | Sirocco II Installation / Review |
| 11 | Nature’s Head Composting Toilet | 1 | Amazon | Toilet Installation |
| 12 | Propane Solenoid Shutoff Valve | 1 | Amazon | |
| 13 | ON/OFF Switch for Propane Solenoid | 1 | Amazon |
Tools
These are essential to build your electrical system. Do NOT cheap out on tools (e.g. using pliers to crimp), or you’ll compromise the performance and safety of your system.
| # | Item | Description | QTY | View on Amazon |
|---|---|---|---|---|
| 1 | Cable Cutter (up to 4/0 AWG) | For large gauge cables | 1 | View |
| 2 | Wire & Cable Cutter (2/0 – 22 AWG) | Nothing to add! | 1 | View |
| 3 | Wire & Cable Stripper (4/0 – 20 AWG) | Nothing to add! | 1 | View |
| 4 | Hydraulic Crimping Tool (4/0 – 10 AWG) | Provides adequate, repeatable results for larger gauge lugs. | 1 | View |
| 5 | Crimping Tool, Single-Crimp (8 – 22 AWG) | Single-Crimp should be used with Heat Shrink connectors to prevent tearing the insulation and loosening the watertight connection (corrosion prevention) | 1 | View |
| 6 | Heat Gun for Heat Shrink Connectors | 1800W, Variable Temperature Control | 1 | View |
| 7 | Digital Multimeter (Voltage, Current, Continuity, Resistance) | You don’t need it until you need it! Your friend when you need to troubleshoot… | 1 | View |
Made with ❤ in our van.
Sharing this tool with others is the best way to say thanks if you found it useful. Thanks for supporting us and for keeping this website alive! See you on the road 🙂
How the Calculator Works
The calculator runs the same steps as Part B of our guide, How to Size Your Van Electrical System, just faster. Here’s what happens behind each number, so you can sanity-check the results (and argue with them in the comments).
- Daily energy use. A 12V DC load uses its current times its hours per day: a fridge drawing 4 A for 10 hours is 40 Ah. A 120V AC load goes through the inverter first, so its watts are converted to amp-hours at 12V, plus 15% for inverter losses: watts × hours ÷ 12 ÷ 0.85. A 1,000 W coffee maker running 15 minutes is about 25 Ah.
- Season profile. Sun Seeker and 3 Seasons size from your summer usage. Snow Chaser adds winter columns (longer nights, heater fan, more lighting) and sizes from whichever season uses more.
- Battery bank. Daily use × 1.25 for lithium (you can use about 80% of it) or × 2 for AGM (about 50%), then × 1.5, 1.75 or 2 depending on the profile, to carry you through cloudy days. The result is rounded up to the next 100 Ah: 60 Ah a day on lithium with 3 Seasons is 60 × 1.25 × 1.75 ≈ 131 Ah, so 200 Ah. The calculator then checks that the bank can feed the inverter, at about 1 Ah of battery per 10 W of inverter: a 1,500 W inverter wants about 150 Ah.
- Solar. Watts = daily amp-hours × 4 (× 3.2 for Sun Seeker, × 4.8 for Snow Chaser). In other words, the panels have to put back your day’s amp-hours in about 3 hours of full sun (3.75 and 2.5 hours for the other profiles). That’s conservative on purpose: panels rarely deliver their rated watts on a van roof. 60 Ah a day is 240 W, so a 300 W kit.
- Chargers. The alternator (DC-DC) and shore chargers are sized from how fast the battery can take a charge: about half its capacity in amps for lithium, a fifth for AGM. The calculator warns you when a charger is too big for your alternator or your battery.
- Inverter. The bigger of your largest AC load and the loads you check as running at the same time, plus a margin: +100 W under 1,000 W, +20% above. A 1,500 W kettle alone lands on a 2,000 W inverter. Past 3,000 W, you’re beyond what our wiring diagram covers.
Our Experience
We used the calculator to size FarOutVan #1’s system, our home from 2017 to 2021: 200 Ah of lithium, 320 W of solar, a Sterling B2B alternator charger (later a Victron Orion XS 50A) and a 1,000 W inverter, with propane for cooking and hot water. In summer, solar covered our daily use on its own. In winter, harvest dropped way down and the alternator charger did most of the work: Plan B in summer, Plan A in winter. That’s why we still think solar plus alternator is the balanced combo for a van.
FarOutVan #2 runs an EcoFlow all-in-one system with an all-electric galley, which this calculator doesn’t size: it’s built for classic 12V component systems. We log what each of our appliances actually uses on our Real-World Power Data page. Handy when you’re guessing the “hours per day” column.
Frequently Asked Questions
How Much Battery Do I Need for a Camper Van?
Take your daily amp-hours, multiply by 1.25 for lithium (2 for AGM), then by 1.5 to 2 for cloudy-day reserve, and round up. A van using 60 Ah a day lands on 200 Ah of lithium. The calculator does this for you and also checks that the bank can feed your inverter.
How Much Solar Do I Need for My Van?
About 4 W of panel per daily amp-hour for three-season use (3.2 W for summer trips, 4.8 W for winter). 60 Ah a day means about 240 W, so a 300 W kit. Roof space is usually the real limit, which is why an alternator charger earns its place. Our Roof Layout Planner shows what fits.
Lithium or AGM?
Lithium (LiFePO4) gives you about 80% of its rated capacity, AGM about 50%, so AGM needs 60% more amp-hours for the same day. Lithium is also lighter, lasts more cycles and is less fussy about charging. AGM costs less up front and can be charged in sub-freezing temperatures. A lithium battery must not be charged below freezing (0°C / 32°F) unless it has a built-in heater.
What Size Inverter Do I Need?
Size it for the loads you’ll run at the same time, not your daily total. A 1,500 W kettle alone calls for about 1,800 W, so a 2,000 W inverter. Induction cooktops and microwaves usually push vans into the 2,000 to 3,000 W range.
Does It Work for 230V (UK/EU) Leisure Battery Setups?
The sizing does. A 1,000 W appliance draws the same energy from a 12V leisure (house) battery whether the inverter outputs 120V or 230V, so enter your appliances’ watts as they are. The parts list and wiring diagram use North American 120V gear, so take the sizes and shop locally.
What About 24V, 48V or All-in-One Systems?
The calculator sizes 12V systems, but the energy is the same at any voltage: a 200 Ah bank at 12V holds about as much as 100 Ah at 24V or 50 Ah at 48V. All-in-one units like EcoFlow are rated in watt-hours, so multiply your daily amp-hours by 12.5 to compare (60 Ah ≈ 750 Wh). More on choosing a voltage in 12V vs 24V vs 48V.
Is My Data Saved?
Yes, in your browser only. Your loads and choices are stored locally so they’re still there next time; nothing is sent to us. Use CLEAR to start over.
This is the third part of our DIY Van Electrical Guide trilogy:
- Van electrical system in a nutshell
- Electricity for dummies
- Battery bank
- Charge sources
- 12V DC loads
- 120V AC loads
- Monitoring
- Wires & Cables
- Terminals & Connectors
- Fuses & Breakers
- Power distribution
- Plug-and-Play (all-in-one) Systems
- Real-World Data
Part B: How to size Your System
- Calculate your power usage
- Size your inverter
- Size your battery bank
- Size your solar
- Size your alternator charger
- Size your shore charger
Part C: Calculator & Diagram
Hi,
Can you please step me through the calculation for the choice of 4/0 wire in the tutorial wiring diagram between batteries/ bus bar/ and inverter?
It seems like overkill to me but maybe there is a reason for this? my main reason for asking is that it is difficult to find 4/0 wire (~107mm^2) where I live with a lot more places going up to ~50mm^2 max (1/0)
Hello all. My family and I are brand new to this rv life. I’m learning the basics but could and would greatly appreciate any knowledge or advice or mentorship, apprenticeship that’s available.
Good day! The information provided is amazing. I like the wiring diagram (app) you offer for sale — well worth it!
However, I have a 1200w solar array and am running a 24v system. Will your calculators cover this configuration by chance?
I could design in app as 600w solar (3s). There are two of those that feed into independent mppts which would wire identically to the mppts, but all still to a 24v system.
Thanks so much again for all of your very hard work and shared knowledge!
At the moment our diagram tops up at 700W and 12V, as described under “Features” section here: https://faroutride.com/product/wiring-diagram/
Thank you,
antoine
As a mechanical engineer with some electrical knowledge, I’m blown away with the depth and detail of your articles. I am in the process of designing the electrical and plumbing system for a grooming van for my daughter. The unusual requirements are:
1. Lots of hot water
2. High capacity Hair / dog dryer
3. Because of the above heat sources, the AC will run more.
I would like to use the following power sources:
1. Shore and generator via an automatic transfer switch
2. solar panels
3. engine alternator
4. Modest battery bank with space to increase as battery efficiency and costs improve.
also considering propane hot water heater and a dual fuel gas generator
As I get further , would like to consult ( pay ) with you regarding my selections. You’ve given me plenty of information to start the process and I am grateful.
Hello,
Unfortunately we do not offer consultation services, sorry.
Good luck with your build 🙂
antoine
From Costco buy a packaged electrical system: EcoFlow Delta Pro Ultra package (12kWh $6,000 or 18kWh, $9,000) for around $500/kWh in a floor space area of 28”x19”. The DIY victron path is highly customizable and costs around $1,000/kWh (if there’s no mistakes). Recharge the EcoFlow Delta Pro with solar, EV, shore power, primary alternator, or secondary alternator. For hot water use an engine heat exchanger and supplement it at the time of use with a tankless (electric or fossil fuel). AC isn’t always needed when using a fan to draw in fresh filtered in air for circulation to manage temperature and humidity.
Thanks for the wonderful resources. We’ve been following along for a couple years while we waited for a van and are finally building!
I had a question about fuses: elsewhere on the website you mentioned to avoid generic fuses and breakers from Amazon, but on this page it appears to link to a pretty generic brand for fuses. Have you used these fuses or are you fairly confident in their reliability?
I am trying to figure out whether to get these or to pay extra $$ for Ancor ATO fuses 🙂
Our intention for ALL the BREAKERS is to link to BlueSea breakers (or equivalent quality).
For small blade fuses (e.g. automotive fuses), it’s fine to use more generic brand.
Sometimes Amazon listings change and it’s hard to keep track, please report it to us if that is the case!
Thank you 🙂
Thank you, that makes sense! I was just talking about the blade fuses; glad to know the more generic brand is probably ok. Though I did find some nice BlueSea blade fuses that light up when they burn out, I might splurge on those anyway just for fun:)
This series is so helpful, thank you!
I’m a little confused though with some of the math.
If I have a 700W appliance, why am I supposed to divide by 12V and not 120V if it’s a 120V?
Thank you!
Because you’re trying to find out the current coming out of your 12V battery bank. See the image in this section (scroll down a bit): https://faroutride.com/electrical-system/#power
PS to my previous post, I meant to state a 100 ah Battle Born battery.
Larry P.
I continue to be amazed by the depth of detail you provide in your tutorials. I’ve searched your prior comments and have not found an answer to my build dilemma: I have a Jackery 1000 and I’ve read your comments regarding it’s potential in a van build. I used it this past summer with no issues but I am now doing a rebuild in which I want to add an addition Battle Born 1000 ah battery to handle most of the 12-volt load and the Jackery for my very limited AC needs. The question is how to wire in charging from the solar to both batteries. My understanding is that they can be charged simultaneously with the two charging managers (one in the Jackery and one dedicated to the BB) managing each charging level. If so, that’s straight forward. If not, I’d like your suggestions.
Related is the 2020 Ford Transit’s 120 VAC power supply located next to the emergency brake. Can I also connect this to the BB battery via an AC-DC converter and leave it connected permanently?
Thank you in advance for you reply.
Larry