FAQ

Watts (W) measure the power of an appliance at a given moment. Watt-hours (Wh) measure the energy it uses over time: a 50 W appliance running for 2 hours uses 100 Wh. Amp-hours (Ah) measure the capacity of a battery. To convert Ah to Wh, multiply by the voltage: 100 Ah at 12 V is 1200 Wh.

It depends on what you plug in. With a compressor fridge, LED lights and phone charging, the usual range is 100 to 200 Ah of lithium at 12 V. The planner works it out from your appliances and the days you want to last without charging.

A LiFePO4 lithium battery lets you use around 80 % of its capacity, weighs about a third as much and withstands many more charge cycles. An AGM costs less to buy, but you should only use half its capacity and it lasts fewer years. The battery comparison tool works out the cost per year of each with your usage.

Enough to put back in a day what you use in a day. It is calculated by dividing the daily consumption by the peak sun hours and by 0.7, which covers the losses. In winter there is less than half the sun of summer, so you need more panels for the same consumption.

Only if you use appliances with a household plug, at 230 V or 120 V. Anything that runs on 12 V or USB does not need one. A pure sine wave inverter is the better choice, and the more powerful it is, the thicker its cables must be.

12 V is the norm in vans, and almost all camper accessories run on it. 24 V pays off in large installations, for example with inverters above 2000 W, because the current halves and the cables can be thinner.

It heats up, loses voltage along the way and, in the worst case, can start a fire. That is why every cable has a fuse that cuts the current before the cable is damaged. The fuse goes as close to the battery as possible.

For small loads and short trips, yes: it needs no installation and you can move it from one vehicle to another. If you have a fridge running all day or spend several days without hook-up, a fixed installation usually gives more capacity for the same money.

They are indicative. They use typical values for consumption, efficiency and each battery type, which vary by manufacturer. Use them to get an idea of the size of each component, check the data sheet of what you buy and have a professional review the installation.

It depends on the country. In Spain, a fixed electrical installation in a vehicle may require official approval. Check with a vehicle approval company or your vehicle inspection centre before fitting it.

No. All calculations are done in your browser and nothing is sent to any server. Only the language you chose is remembered on your device.

Yes. All the tools are free and no sign-up is needed.