Powerhouse Off Grid
A handful of calculators to help you plan your build. Pick a tool below.
Solar Charge Calculator
Battery size, panel size and time of year — see your daily top-up and how loads affect it.
Voltage Drop & Cable Size
Check a cable size against your run, or find the smallest size that'll do the job.
DC-DC Charger Calculator
Vehicle and house battery voltage, drive time — what to expect on arrival.
Solar charge calculator
Set your battery, your panel and the time of year — we'll estimate the daily top-up in real watt-hours, not house-sized kW.
Van consumption calculator
Not sure what your gear uses? Tick what's on board and dial in how hard you run it. Tapping a selected option again clears it.
Ticked items add up to 0 Wh/day
Fills in automatically from your ticks above — drag to fine-tune, or if you've got exact figures from a device.
Daily solar top-up
With your loads running
Estimates use average UK peak sun hours by month and typical system losses (cabling, MPPT, temperature). Actual output varies with weather, exact latitude, roof orientation and battery age — treat this as a planning guide, not a guarantee.
Want a system properly sized and fitted around your van? Get in touch with Powerhouse Off Grid.
Voltage drop calculator
Set your system voltage, run length and load, then check a cable size against it — or let us tell you the smallest size that'll actually do the job properly.
As a rule of thumb: 2% or under is a great result, and up to 5% is generally treated as the borderline for non-critical circuits.
Your chosen cable
Recommended minimum
Based on standard copper conductor resistance at 20°C, calculated round-trip (out and back) for a two-core DC circuit. Real-world drop can be higher with connector losses, high ambient temperatures, or bundled/derated cable runs — this is a planning guide, not a substitute for proper cable calculation on safety-critical circuits.
Not sure which cable to buy, or need it fitted properly? Get in touch with Powerhouse Off Grid.
DC-DC charger calculator
Set your vehicle and house battery voltages, your battery sizes, and how long you're driving — we'll show what to expect on arrival, tapering the charge rate the same way the charger actually does.
Not an efficient setup. Charging a 12V house battery from a 24V starter battery is unusual and wasteful — worth a proper conversation about your setup before spending money on a charger.
Expected on arrival
At this rate
Modelled as a tapering charge curve — full configured current up to around 80% state of charge, then gradually reducing through absorption as the battery approaches full, same as the charger's own 3/4-stage algorithm. Real-world results vary with alternator output, cable run, ambient temperature and battery age — this is a planning guide, not a guarantee.
Not sure which charger and cable size your setup needs? Get in touch with Powerhouse Off Grid.
