You are probably a typical boater in that everything is fine while continuously cruising or plugged in, but when you want to sit somewhere on the cut for a few days you don’t want to be running your engine for hours on end!
So is solar the answer?
The answer to that question is YES, it’s PART of the answer. First and most important thing to understand is solar does not mean you can forget about the problems and have an abundant supply of power. You STILL need to be just as economical with your power as you usually are BUT if you are, you won’t need to run your engine – possibly at all!
So what else should I think about?
The key secret to living off grid and relying on a 12v battery bank as your source of all power is to run as MUCH as possible at 12v. So in an ideal world a 12v fridge, 12v TV (some very good flat screen with integrated DVD ones available now not like the “old” days) and have 12v sockets allowing car charges to be used for all our modern technology such as mobile phones and tablets etc. The other great new technology is LED replacement bulbs that consume next to nothing.
Most boats will have Inverters fitted that generate 240v mains power from your batteries and whilst useful do be aware that they consume a lot of power in providing that 240v and thus running even the most economical of mains powered devices such as a lap top charger consumes a lot of power. Any 240v object that’s heats up should be avoided wherever possible as heating elements consume sometimes 200 amps or more… The most common heavy duty mains device is a washing machine. The trick here is to use the inverter BUT while the engine is running a high rate of charge is being delivered from the engine alternator to “offset” the high rate of discharge through the inverter. Below are a number of key tips to “eco” your boat..
Renewable, Clean, Money Saving, Low Maintenance
Try to get to a point where you don’t need to reply on mains power via the inverter as MUCH as possible. Of course you may need to use the inverter to run heavy duty items like the washing machine, BUT you would also run the engine at the same time to make sure a big charge is going in from the alternators while you are drawing a big charge to run the inverter/washing machine.
It also pays to remember the golden rule – if you don’t need it – switch it off! Thus if you don’t need mains at the moment, turn the inverter off. These simple tips above will make a huge difference to your life on the cut AND reduce the amount of solar you need. A boat equipped as described above will comfortably sustain itself on a 430W system. A boat with say a 240V fridge and a 240V freezer will need to consider at minimum 645W of solar and probably look at 860W to be “comfortable”.