Choosing a system is generally based on a number of criteria
1, How Economical Are The Consumers On The Boat?
A well configured boat for off grid living will be largely 12v based and certainly have a 12v fridge, probably 12v sockets for charging devices up and likely a 12v TV and LED lighting. This is kind of a “perfect” configuration making no use of an inverter to generate mains which requires a lot more power.
Most boats however will require some use of an inverter perhaps just for a TV which is not too bad (all mains electronic devices these days are fairly low power draw and although not as efficient as running 12v units they do not place massive loads on an inverter) but often for a mains powered fridge which is much more “amp hour” hungry and sometimes a mains powered freezer too.
Part of the process is calling for a chat so we can find out what you are running and make a recommendation on system size. Basically the more power you draw (and inverter based mains kit draws a lot more) then the more solar you will need.
Sometimes it might be better to rethink your power draw and change things for lower voltage equipment than have less solar!
NOTE THAT REFRIGERATION IS THE BIGGEST ISSUE AS IT IS ON 24 HOURS A DAY. NO MATTER HOW ECO A 240 FRIDGE IS IT WILL ALWAYS BE FAR MORE POWER HUNGRY THAN A 12V FRIDGE DUE TO 24 HOUR INVERTER USE AND THE POOR EFFICIENCY OF TAKING 12V AND STEPPING UP TO 240V.
2, Battery Bank Size
The battery bank size also dictates the amount of solar required to ensure its topped up on a daily basis – again the bigger the bank the more solar is required. One very common issue I come across on a regular basis is banks that are way too small. The customer is anxious to get solar as they struggle on a daily basis with power. On chatting through I find they only have two 100 ah batteries and are trying to keep a fridge going and run a TV lights etc. So you may need to have a look at your battery bank size as well.
What type of user are you?
3, Are you just an occasional holiday boater or live aboard?
A holiday boater only wants the batteries to be topped up when they get to the boat and is unlikely to stay somewhere on their travels for long so probably only needs small scale solar. A continuous cruiser needs power on a daily basis but mixes cruising with stopping for a few days. So a good solid mid range system is often best. The boater living on a linear mooring with no power needs the larger system as they are not wanting to run an engine every day just to generate power.
As always budget comes into it. In all truth you can never have too much solar as the controller backs off once it’s done its job. The more you have the quicker the batteries top up and the more you can draw. So if you want to be totally safe and secure that you have enough power then over specifying the system is the way to go.
If you are limited on budget I can accurately advise whether a smaller system that you really need will offer any advantage – it usually will but at the lower budget where a larger system would be better it may not give you the full autonomy that the larger system would but will almost certainly help. I am very much a believer in setting your expectation levels before you commit to buy.
However, from experience of installing systems on more than 2000 boats, generally these are the systems chosen.
- Holiday boat and/or primarily marina based using the boat every now and then and assuming it’s fairly 12v orientated. Then the 430w 2 panel is a good option.
- Live aboard continuous cruisers tend to go for the 3 panel 645W system. This is an excellent all round system that will output a charge rate of 40A on a reasonable spring or summer day but with a good high average on the worst of days. While I would still always recommend 12V refrigeration this system does support a 240V fridge with inverter run 24 hours well as long as your battery bank is capable.
- Live aboard boats on moorings with no power such as linear moorings have the greatest challenge in that they are not naturally needing to move often and so really want to minimise or eliminate engine run time so the larger 4 panel 860W system, with the larger 60A controller is the usually the best way to go, guaranteeing a good high average output in most conditions.
- Large wide beam barges off grid with largely 240V systems. The other category for larger systems tend to be large barges with heavy 240v usage and/or very large battery banks. In these instances the 860W system with 60A controller is the likely minimum but consideration of a larger custom designed Bespoke System is usually the best way forward.
- Remember that the more solar wattage you have the higher your average daily output will be and thus the need to monitor and be more “careful” with power reduces considerably as the system size increases. In short – You can never have too much solar – but you can easily have to little.
OUR MOST POPULAR GOOD ALL ROUND SYSTEM FOR MOST BOATERS IS THE 3 PANEL 645W SYSTEM
OUR MOST POPULAR GOOD ALL ROUND SYSTEM FOR MOST BOATERS IS THE 3 PANEL 645W SYSTEM…
So in summary really the first phase is call for a detailed chat and we can weigh up the options based on how your boat is setup, how much you want to sit without running the engine and budget.
Call if you would like to discuss sizing the right solar system for you: 07810 885734