How to configure solar panels for RV electrical system?

MPPT/PWM solar controller (MPPT is maximum power point tracking, usually 20-30% higher than PWM power generation).
There is a certain space on the top of the RV to install solar panels. According to our survey, the solar panels of the general RV are 400W-800W. Here we will share the most reasonable RV solar panel power generation design. Usually, we choose even numbers when installing solar panels, because we need to involve series and parallel. If your RV is a 12V system, the best working voltage of the MPPT solar controller is 24V-36V. Of course, many MPPT controllers also say that it can work at 3V higher than the battery, but the RV is not like an off-grid solar system. The lighting and installation angle are both extremely demanding for RV, so we choose a slightly higher one. We have also checked a lot of solar panels used in RVs, which are basically around 18V, so we suggest 2 pieces in series and then parallel. If you use an 800W solar panel, it is most ideal to choose the 12V/80A MPPT solar charge controller. We have seen a lot of solar panels installed, but the actual controller did not reach, and it still can’t generate much electricity. Because of the different lighting in various places and the different parking positions of the riders, it is impossible to give an accurate answer to how much electricity the 800W solar panel can generate. However, we investigated most of the RV users who installed 800W, and they can generate about 2 kWh of electricity in 3 hours from 11:00-14:00 noon.

Here, let me share with you the experiments we have done. In fact, we have seen many RV users install a lot of solar panels on roofs of different shapes and sizes. Most users will find that 800W solar panel installed, but only has a charging capacity of more than 200W or even more than 100W. Here is my experience, because most of the single solar panels on the RV have a voltage of around 17-21V, so many users and even RV factories connect two pieces in series and then in parallel. An important theory here is that if solar panels with different power are connected in series, the current is output at the smallest piece. In layman's terms: 150W and 100W are connected in series, the actual effect is only 200W but not 250W, so when doing the test, the actual power generation of one group of 150W+100W and the other group of 100W+100W are the same.

We saw a lot of users installed some very small pieces on RVs. If this pieces is 20W and another piece of 100W, it can only be 40W, which will be a lot of waste. Will the parallel connection of multiple groups of different powers have an impact? For example, we have one group of 150W+150W, and two groups of 100W+100W. Seeing that the power is 700W, but the actual power generation efficiency has not been reached.

The reason is that the parallel of solar panels with different powers into the MPPT will affect the maximum power tracking. Therefore, the suggestion is to install an even number of boards of the same size on the top of the RV, so that the power generation effect can be highest. Composed of a double number in the smallest unit, for example, it is recommended not to install 100W in some places and 50W in some places. just install at 50W. In our actual test, if the installation is reasonable, use the MPPT with good performance, the power generation efficiency can reach more than 50% when the sun is not particularly good, and it can reach more than 85% when the sun is big occasionally.

Therefore, when choosing to install solar panels for RVs, you must pay attention to this detail. Don't reduce the overall power generation efficiency just because you want to increase a small piece of usable space.

Summary: When installing solar panels on the roof of your RV, choose an even number of solar panels of the same model to achieve the best condition.

See more for Basic RV Electrical System Guide 2022 >>
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