Can I use a solar panel to charge the engine battery?

QI have a 2011 Bessacarr E510 on a Fiat Ducato and have solar panels installed. I wanted to confirm if it is possible to charge the engine battery off the panels.

I was told by the installer that, if I did this, it might cause a problem with the electronics on the dashboard, but I’m not sure why this would be. Any advice would be gratefully received. Jimmy Kennedy

AThere’s a simple reason why the person who installed your solar panels told you that. It’s that they don’t have a clue about installing solar panels or motorhome electrics!

It’s not only possible to install solar panels in this way, but I strongly recommend it.

In order to charge both leisure and starter batteries, a special kind of regulator is needed. The regulator is the box that the panels are connected to and which, in turn, is connected to the leisure battery. I hope your installer used one. If he didn’t, your batteries are going to need replacing very soon.

It transforms the voltage from the panels, which is likely to be in the region of 17V-21V, to a voltage suitable for charging a battery, around 13.8V.

Most can only be used with the leisure battery, but there are plenty available that can be set to charge both the leisure and the starter batteries: these are known as dual-output solar regulators; some are better than others.

Installing a regulator is a simple job, but running the wires to the starter battery can be tricky if you want a neat job done. A reputable installer will be able to do it for you or you may be able to do it yourself if you have the tools.

A word of advice: check the panels have been installed correctly before proceeding!

Andy Harris