Posted: Mon Jun 27, 2011 8:46pm

We are looking to install a shoreline F40 chest freezer to go under our dinette, we are full time cruising and would like to know what size solar panel needed to keep the batteries topped up, also 12 volt fridge in use. many thanks Pete

Posted: Tue Jun 28, 2011 7:24am

Fist you need to do a power audit for your use of the electrical items on the boat (see tb-training.co.uk). Lets look at just the fridge and freezer. Taking both together they will require something like 100 Ah of power per day assuming a 50% duty cycle. that is about 1200 watt hours per day or 1.2 kWh per day. You will need to put back into the batteries up to 40% more than you took out to get them back to where they were before you started so that makes the figure about 1.7 kWh per day. The output of a horizontal 1Kw panel produces (you can check this on Google) about 0.32 kWh per day in winter so you will need to install about 3000 watts worth of panels. In high summer perhaps 1/10th of that. At this time I doubt you will have enough roof space for mounting them and I have serious reservations about the cost effectiveness of trying to exist on solar power alone IF you are into fridges and freezers. A water pump and a few LED lights is another matter. Data source: http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php Tony Brooks