The String inverter

A string inverter is the simplest way of converting direct current into alternating current. The device has one or more connections to which a string of solar panels can be connected. As explained in our general description, a string is a number of solar panels connected in series.

The disadvantage of a series-connected circuit is that the current is only as strong as the weakest link. Compare this to a river with a narrowing in it. The amount of water that can flow through the narrowing determines the amount of water that eventually arrives; even at the point where the river is wide. If we translate this to the solar panel, it is not the voltage but the amperage (Ampere) that is decisive.

When it comes to string inverters, it is sometimes suggested that all solar panels are affected if one panel is in the shade. This is incorrect! Solar panels are equipped with bypass diodes.

In general, there are three bypass diodes in a panel. The idea is that each group of solar cells increases the voltage while the current remains the same. If the current of the group of cells is too low, the bypass diode is switched on and the group of cells is skipped.

In principle, therefore, a string inverter offers an excellent solution for getting a good return from your solar panels. The string inverters that Robisol uses are equipped with arc detection and other safety features to ensure that your installation functions properly. Slightly larger inverters are often equipped with two or more MPP trackers, which ensure that the yield from a string is optimised. This is useful, for example, if you want to install solar panels on both sides of your roof. The inverter will then ensure an optimum yield on each side.

Robisol generally supplies Growatt or Huawei string inverters. These are major brands with reliable technology. If you have other preferences, we will be happy to adapt to them. It is desirable for you to have an internet signal available at the location where the inverters are installed so that you can view your production data and we can monitor your installation remotely.

Below you will find the product sheets of a number of String inverters supplied by Robisol. The terms 1- and 3-phase are relevant here to indicate whether the energy is fed back through 1 or 3 groups. In installations exceeding 3600W, Robisol will generally install a 3-phase inverter so that the energy is neatly distributed across the groups of the mains.

Growatt 1-fase
Growatt 3-fase
Huawei 1-fase
Huawei 3-fase