What is the basic solar panel

Design of a solar system

We would be happy to give you a few recommendations on how you can design a solar system for mobile homes, boats and other off-grid applications.
There are basically only a few, but important, points to consider:

  1. Your electricity consumption
  2. The sun exposure on site
  3. Your mains voltage - 12 or 24 V.

When you have clarified these points for yourself, you can start looking for a suitable solar module.

1. Your electricity consumption:

Determining this is usually easier said than done, because it is not only important to know what performance the individual devices have but also how long they will be operated. If you want to make coffee, for example, it has an output between 700 and 1500 watts, no solar module in the world can deliver a comparable output. However, the kettle may work for a maximum of 10 minutes a day.
If we now calculate the energy requirements of the kettle, we get:

Electricity consumersOperating time per daypowerconsumption
fridge8 h110 W880 Wh
Laptop2 - 6 h140 W280 - 840 Wh
coffee machine10 min1500 W250 Wh

We would be happy to expand this table for you, just tell us what else should be added.

The amount of energy of 250 Wh can certainly be provided by a solar module. A 110 Wp solar module provides enough to operate the kettle after just three hours.
This does not mean that you have to wait three hours to make your tea, but that after three hours your battery is 100% charged again.

A refrigerator only works about 1/3 of the day, which is why we only use 8 instead of 24 hours.

If you want to design a solar system for your caravan, for example, you should make this calculation to be on the safe side (i.e. always with the highest consumption and the longest operating time) for your largest electricity consumers.
After you have determined your needs, it is necessary to think about the solar radiation on site, because this indicates how much power you can expect from your module.

2. Sun exposure on site

The sun delivers a radiant power of 1367 W / m2, however, some of this radiation is absorbed by substances (aerosols) in the atmosphere. The final radiation output that arrives at your solar module also depends on the angle of incidence. In addition, the radiation output changes over the year, so in Germany there is an average of 800 and occasionally 1000 W / m in summer2. in winter the value is around 400 W / m2.

What does this mean for your solar module?
Every manufacturer determines the output of a solar module with an irradiation of 1000 W / m2because that's what the standards dictate. If your solar module is now exposed to solar radiation of 800 W / m2 exposed, it delivers 80% of its specified performance. The calculation looks like this:
If you now calculate that for an average summer day in Germany for a solar module with 100 W, you will get this result.

The output of the solar module will range between 80 and 100 W depending on the summer day. If you now travel to more southerly areas, such as Spain, the output of the same module can even exceed the output labeled by the manufacturer because the solar radiation there is over 1000 W / m2 can lie.

This is the basic theory that lies behind every solar module and that has to be considered when designing it.

3. Mains voltage 12 or 24 V.

Most solar modules that you can mount on a motorhome provide enough voltage to charge a standard 12 V battery.It can get more complicated for you if, for example, you have a system voltage of 24 V in your motorhome or caravan. This is a minor matter, but one that you definitely have to consider when choosing your solar system.

If you now have a system voltage of 24 V, there are a few ways in which you can still use 12 V solar modules. The simplest thing is to connect two solar modules in series or to mount a 24 V solar module directly. These can then feed power into your 24 V network without any problems.

After you have clarified these points for yourself, you can start choosing a suitable solar system.
If you are interested in our products, take a look in our product catalog to see if we have something suitable for you. You can get 12 V solar modules from us; 24 V solar modules and complete solar sets for mobile homes and more.
If you are not interested in a permanent installation, then take a look at our mobile solar system.