Invertor - advice/reassurance

We have a Bestek 300W inverter which happily charges our Mac Air, a full size mains printer, camera battery chargers and even my heated, travel hair straightening tongs, though the latter are on the limit of its capacity. Where possible we use dedicated 12V chargers ie for iPad, iPhones and my husband’s electric shaver. Ideally, we use the inverter during the daytime so that it’s drain on the battery is reduced by 110W of solar panel.

Your laptop should be fine as long as you are using the provided cable and transformer. That is as long as you charge it like at home. However I would power it off when charging and there should be no problem with the wave shape. Off mains the laptop works on 19 volts ish from the battery. If you use it plugged in to the inverteo  and the battery is dodgy the wave shape could damage the electronics. The invertor has a built in fan which is what you can hear.  Hairdriers are a no no unless you have a massive invertor. The 12 volt ones will  also probably blow the caravan fuse.  Most tablets and phones can be charged from the leisure battery as they run on 3.6 volts DC. To be safe you need a usb converter  that you plug into the 12 volt socket in the van. A word about solar panels is never to charge devices directly as they can throw out 17 volts which may cook a phone battery.