Plan your power system
Seven steps from today’s electrical setup to a plan you can keep. Leave anytime: your place saves with the plan.
The steps
- 1
Truck and electrics
What’s on the truck today?
Electrical starts from your truck’s factory battery and alternator where they’re on file. Electrical parts on the build sheet show here.
- 2
Loads
What draws power?
Start with the fridge: it runs day and night and is usually the biggest draw. Then lights, fans, radios, chargers and an inverter, each on the battery it draws from.
Answered byElectrical
- 3
Batteries
Which batteries, and how big?
Electrical fills in the factory battery where it’s on file. Add an auxiliary battery and it shows how long each one lasts with nothing charging.
Answered byElectrical
- 4
Charging
What charges it?
The alternator (its factory output where it’s on file), a DC-DC charger, solar and shore power. Electrical shows whether charging puts back what the loads take. Shore power never counts toward days off-grid.
Answered byElectrical
- 5
Days off-grid
How many days can you stay put?
The Electrical diagram gives days from full and days from now for each battery, parked, with your loads and charging. Save it to the plan to keep it with this path.
Answered byElectrical
- 6
Weight
What does it weigh against payload?
Batteries are heavy. Electrical works out what its parts weigh; put them on the build sheet with their weights so they count against payload and GVWR.
Answered byElectricalBuild sheet
- 7
Review
Review and keep
What the plan adds against Actual, the weight, and the open checks.
Each step opens Electrical with your truck’s factory battery and alternator filled in where they’re on file. Add the loads, the batteries and what charges them, and the diagram shows how many days each battery lasts. The build sheet weighs the parts against payload. With JavaScript on, this page keeps your place and your answers in My garage.
Camp power, answered
Why start with the fridge?
It runs day and night, so it’s usually the biggest share of what a camp uses in a day. Electrical counts it from the maker’s published average draw where there is one, which is far below the rated current printed for sizing the wire.
Does shore power count toward days off-grid?
No. Electrical records shore power on the diagram, and it never counts toward days off-grid. Solar, a DC-DC charger and the alternator are what it counts as charging.
Why is my runtime unknown?
Because one load with no power rating, or no battery it draws from, could be the biggest one. Electrical shows the known part labeled incomplete until every load has a rating and a battery. The path leaves the same gap as an open check.
Use at your own risk. These calculators are here to help you plan and to inform your decisions, not to sign off on a build. Many numbers are estimates worked out from factory figures, and some factory figures are not yet confirmed. Check every number against your own truck, its manuals and a qualified shop before you buy parts, cut, weld, lift, regear or drive on it. Long Range Desert Tools is not liable for anything you do based on these calculators or their results. The full terms are in our policies.