While talking with people when cruising I have noticed one thing that has the ability to cause the biggest headaches for a lot of people: electricity. How to make it, store it and use it efficiently while staying in budget.
Keep it simple sailor or the ‘KISS principle’ is a saying commonly bandied around by a lot of cruisers. But that does not mean you have to have a bare bones boat electrically to keep it simple sailor. How do we reduce the stress and keep it simple without compromising lifestyle?
To make life easier while still keeping our creature comforts we have simplified our systems by following two simple principles: minimise moving parts and reduce power consumption.
Start at the beginning
It really is better to step back and, rather than saying we need more, the best thing to do is consume less. Reduce the power consumption through operational changes.
Of course this goes hand in hand with improving the efficiency of the equipment you have to also reduce consumption. To go the ‘more’ route most of the time will mean bigger, more battery banks, more wires, more regulators, additional alternators and bigger solar arrays all being required to accommodate the increased usage. It is like a snowball, the bigger it becomes the harder it is to handle.
When meltdown occurs it leaves a big mess to clean up.
By minimising a vessel’s total electrical requirements, you should be able to avoid the need for a generator. These are possibly one of the highest maintenance systems that anyone can put aboard their boat.
We have been on other boats and if a phone battery is flat or kids want to watch TV the inverter is turned on or the generator is started up. I have witnessed a cook turn on the inverter to cook toast in an electric toaster but first they had to be sure no one was using other appliances. I missed seeing the initial peak load on the amp meter as the element heated, but did see the 12 volt load was in the order of 100 amps for the next couple of minutes.
We discussed power usage and discovered they tried to use an electric jug to heat water for tea and coffee but that was not very successful. To top off the power usage there were two fridges and the microwave drew over 80 amps when in cook mode. Another problem was that all the cabin lighting was high wattage incandescent bulbs. When the kids wanted to watch the large television the inverter was switched on.
I was not at all surprised that they had a lot of problems with the batteries and always returned to the dock at the end of a weekend away with very low batteries. The high power usage was a major problem because the vessel was unable to be away from the dock for more than a few days.
In an effort to get better endurance they were looking at buying a generator. After a look at their power consumption we worked on a plan. Most of the problems faced by this family were problems we had already worked through on our vessel. So the first part of the plan was to identify equipment in need of replacement, or modification. Other parts of the plan looked at the operation of equipment that would help conserve power and not leave their batteries in such a state of discharge at the end of the weekend.
What to do
It is true that in this day and age electric and electronic gadgets should make life so much easier for the majority of us. Unfortunately however a lot of the time these gadgets have complicated our lives and given us more than the odd headache.
The way I see it the problem is that while there is a lot of information out there explaining how things work, you need a lot of time to read it all. Really most of us do not have that much time to sort through all the options and functions available and, not being experts in the field, it is hard to compare apples with apples.
So the next thing to do is put our trust in the experts, unfortunately a lot of experts/sales people miss the point when frustrated sailors go shopping. Instead of helping reduce the clutter a lot are sold components or systems that only complicate things more.
Lets see if I can explain how we simplified things. Here are several things we did to reduce power consumption and make our electrical system efficient.
The first thing we did was to check the power connections were clean and tight. To do the job correctly the connections were removed one at a time then treated to a good clean and a thin smear of corrosion inhibiter before retensioning.
During the work the power cable condition was inspected to make sure the insulation was clean and in good condition.
One job that did take a lot of time was removing the redundant cables. Due to the age of the boat we had lots of unused wires choking up the cable runs. The other problem was the wires went in all different directions under the floor or through the cable trays under the deck head. Previous installers in a hurry to do a quick job found ways from point A to B by cutting a number of holes and just doing their own thing.
The bulkhead behind the power distribution panel looked like it had vomited a technocolour of wires and very little was numbered or labelled. So the first tidy up was a little time consuming but the good thing was some really bad connections were made good.
As it turned out, one bank of batteries was not connected and the main distribution bar for the DC ground had some loose connections. Those loose ground connections would explain entries in the log about intermittent problems with HF radio, hum in the stereo and lights dimming.
One of the tools necessary to manage power onboard properly is a battery monitor. There are several well-found units available. While simple to operate and install most are only capable of managing one primary bank and a start battery. If you have more than one primary bank then it will be necessary to install additional units.
Keep it simple, have one primary house bank. Managing two or more house battery banks only complicates things and there is nothing to be gained. Overall the total power consumed will still be the same no matter how many banks you have.
As I said earlier these battery monitors are simple to install, however they do need to be wired correctly. If circuits bypass the monitor by having wires with a connection directly to the batteries then the total percentage of usage or charging will not be correct.
If you have a monitor previously installed and are unsure if all circuits are connected, check for direct connections to the batteries. It is likely things like bilge pumps, monitoring systems and stereo memory will be directly connected to the batteries. These may be connected to a fuse block with a direct connection to the batteries so they cannot inadvertently be turned off.
You should also check power consumption by turning on all equipment one piece at a time, checking the amp meter for increased current draw. Before starting the test you will need to ensure the charging sources are turned off or disabled.
Our boat has a modern inverter with a built in multi-step battery charger, but once we leave the dock we very rarely use it. By carefully selecting components, we no longer need an inverter for charging our phones and running or charging our TV, laptop, printer and music players etc.
Reducing the load on the batteries means they are always at a higher state of charge, which makes them easier to maintain and also results in longer life.
Do not fall into the trap of purchasing an inverter just to use the 240AC adaptor/battery chargers that came with a laptop, appliance or phone. When we first got a laptop I knew we needed a DC to DC converter. These are also sold as an airplane and auto laptop/notebook adaptor.
Off we went to the local tech. shop but I could not see any. So I asked where we might find them, the sales staff listened intently as I explained what I wanted and I was then poorly advised to buy
an inverter to do the job.
The sales staff looked at me strangely as I tried to explain the losses incurred with what they suggested. To use their proposal I would need to convert 12 volts DC to 240V AC then back to approximately 19V DC so I could charge the laptop. I wanted to drop the very inefficient step of converting 12V DC to 240V AC. What I wanted was sitting on the shelf, all we needed to do was look around some more, so in a lot of cases it boils down to what the sales person does or does not know.
I am not down on inverters and I think cruising yachts should have one. The great thing about having 240V AC on board is the range of cheap kitchen appliances and tools available. I think any one who has been boating for a while has been disappointed by the range of 12V appliances that are firstly expensive, secondly have a very short life and thirdly do not usually work as advertised.
Our Pure sine wave inverter does a great job of running our washing machine and kitchen appliances. With an inverter it is wise to plan your usage. Do not switch it on half an hour before you are going to use it. We have also found the power save option is usually a disappointment.
So the best thing to do is operate it immediately and shut it down after use. An inverter uses power from the moment you turn it on.
The amount of power varies with the brand you have, some do not use very much while others are quite heavy just in idle mode. Idle mode is when no appliances are in use or turned on.
An inverter changes the voltage type from DC to AC, the output power measured in Watts is always less than the input power due to inverter efficiency being less than 100 per cent. Efficiency may vary from something just over 50% when a trickle of power is being used, to around 90% when the output is approaching the inverters rated output. An inverter when turned on will use some power from your batteries even when you are not drawing any AC power from it. This results in the low efficiencies at low power levels.
The power that is lost as electrical energy (10% to 50%) is wasted heat dissipated by the inverter: Watts = voltage multiplied by current in amps.
Another important factor involves the wave form and inductive loads; for example an appliance where an electrical coil is involved, which will include anything with a motor. Any waveform that is not a true sine wave (as an example: a square or modified square wave) will be less efficient when powering inductive loads. The appliance could use up to 20% more power than it would if using a pure sine wave. Together with reducing efficiency, this extra power usage may damage or shorten the life of the appliance, due to overheating.
For a quick explanation about the different inverter outputs, the pure sine wave type replicates domestic and shore power wave purity enabling any appliance to run from it. In a nutshell anything plugged into the power point will work like it does at home. A modified sine wave, or sometimes marketed as quasi sine wave, partially simulates domestic and shore power wave form enabling the majority of appliances to run from it. The exceptions, the minority of appliances, that will not work on modified sine wave are as I explained earlier: an appliance where an electrical coil is involved, for example washing machines and thyristor controlled appliances like light dimmers and speed controlled cooking appliances and drills. Some laptop chargers, phone chargers, and TVs won’t work so if in doubt; go for a pure sine wave inverter.
Due to the fact there is a lot of wasted power while running an inverter, this is the reason on our vessel we use as many DC:DC converters instead of an inverter, once away from the dock. These convert the 12VDC to what is necessary either lower or higher voltage DC with a small loss, a lot simpler, safer and cost efficient.
Depending on the type most DC:DC converters are universal and can be used for a wide variety of charging and powering applications. For running your laptop, power supplies are available in different sizes and are manually configurable for the correct output. All you need to do is to read the settings on the back of your AC adapter and purchase the corresponding DC:DC converter.
As an example a 19V 65W AC adaptor can easily be replaced with a 90W DC:DC adaptor with a configurable 19V output. For the netbooks/notebook a 50W in-car, mini notebook power supply would be good.
If you have a Dell laptop the best DC:DC adaptor is the one they supply because the laptop talks to the charger and if an after market charger/adaptor is used then it will not recharge the battery.
One thing to keep in mind is that laptops, tablets and netbooks have new models coming on the market with lower power consumption all the time. A friend recently replaced their old laptop with a newer model and was pleasantly surprised to find it consumed half the power the old one did while processing at twice the speed.
Available with a 12V input, USB chargers can be built-in, or plug in units are available. You will need to know the output current so you can match it to what you want to charge.
Shop around, a heavy duty dual USB charger socket with an output of 5V/2.5A has an output capability of 2.5A (12.5W) from one socket. This is the correct output required to charge your iPad/Android tablet/e-reader at the full, normal rate; or two iphones/Android phones/ipods/MP3 players simultaneously.
Yes our USB outlet can even charge up our Samsung phone, a lot of standard USB chargers will not.
The good thing is that DC:DC convertors can be very efficient, some are 93% efficient meaning the loss of conversion can be as low as 7%. Not bad if compared to the losses incurred by an inverter (DC:AC converter) that can be as high as a 50% loss using low power devices.
Where does that power go
Usually an efficient way to cool a cabin is with wind chutes attached to cabin hatches, but to be effective the use assumes a breeze and strong enough that the boat can swing into it. On still nights, cabin fans can make the difference between sleeping and not. A typical six inch cabin fan can draw about one amp, but efficient fans draw only 0.4A. In eight hours the accumulated difference can be up to 4.8Ah per fan.
Televisions are available with 12V inputs and several brands come with a universal cigarette lighter plug power cable. This removes the need of using an inverter or generator just to watch the TV.
The other good thing about these modern TVs is most come equipped with a built in DVD player, so this removes the need to purchase a separate DVD player. If you connect the TV audio output to the boat sound system you can have great sound while watching your favourite show.
No one is willing to watch glitchy television any longer, so the choice is between the older standard LCD television and the newer HD LED versions. LED TV has the lowest energy consumption, especially when you turn down the backlight. A 19” LED HD TV will consume about 36W, that is 3A so, if you watch your favourite shows for four hours a night, it will consume 12Ah. While this might sound like a lot, in most cases it is less than running a laptop for watching movies, in the case of a laptop consuming 65W could save approximately 9.5Ah an evening.
While talking about sound systems, the clarity and quality of a sound system depends more on the efficiency of the speakers than that of the electronics, look for high quality speakers.
If you have ever checked the sensitivity rating on a speaker you will usually find that it is in the 90 decibel range. This means that at a distance of one metre from the speaker, the speaker will output 90 decibels of sound with only one watt of power. You may not realise it but that is pretty loud. For a non-occupational setting, this is the recommended maximum level you can listen to safely for one hour in a twenty four hour day.
Combine that with the additive effect of multiple speakers and you easily reach a 100 decibel level, enough to cause pain and or ear damage. Three or four watts will supply enough power for comfortable listening at a distance.
Keep in mind that acoustic power operates on a logarithmic scale. This means that past a certain point you are only going to get a small increase in the sound level even though you are increasing the power output enormously.
Power consumption can be significantly reduced by having a high quality low wattage sound system. So those 100 or 200 watt sound systems are not really necessary and are more than likely just going to suck up power, a good quality low wattage system is better value in the long run.
If you want to roughly check the stereo system manufacturer screative measurement of output wattage figures, check out the fuse size a 120W system will have; at a minimum a 10A fuse.
Lights can seriously consume a lot of power; we changed our most used cabin bulbs and external bulbs to LEDs. Our cockpit lights are LED pond lights, great for outside due to them being waterproof and they do not consume much power.
The cabin lightbulbs were fairly easy to upgrade; bulbs are available off the shelf. Only one bulb was trouble to get a replacement, but with a little work we made an adapter to take a standard LED assembly.
It would have been simple to replace some of the light fittings with fluorescent light fittings. But I was not convinced this was the best way to go due to the electrical noise these fittings can produce. This electrical noise can cause interference with the radios, TV and instruments. The replacement LED bulbs were quiet electrically and had
a better life expectancy.
After the change over to LED lighting we were able to easily save approximately 24Ah in the course of an evening.
One light that can deplete the battery bank is the anchor light. During winter the light is on the longest time and this is usually when energy is hardest to replenish. Low wattage replacements are certainly worth looking at, it is possible to save almost 10Ah per night.
Please do not go the garden light route, these are made to operate for three to five hours after the sun sets and, as the price becomes cheaper, so does the quality; the light output suffers really badly. On several occasions we have almost collided with vessels relying on garden lights to do the job
of an anchor light.
A better way is to use solar power to control an anchor light, use the automatic output available on most of the newer solar panel regulators. When the sun goes down the regulator switches on an external output and then, when there is enough light in the morning, the output is switched off. An effective and cost efficient way to control the anchor light.
Do you really need a fridge and a separate freezer? If the answer is yes then you need to make them as efficient as possible. For a freezer the thicker the insulation the better, start with a minimum of 100mm but 150mm thick is really necessary, while 100mm for a fridge should help the refrigeration condenser unit cycling efficiently.
A good lid seal is very important to keep the cool in and moisture and warm air out. Our vessel did come with a second fridge/freezer but the lack of insulation and several design faults meant it just consumed power at a great rate. The day we decided to shut it down and remove it changed the way we operated to a large extent. Plus, what
a load was taken off our mind.
The draw back with most commercially available fridges and freezers is that these units do not really have enough insulation to be electrically efficient. It is a real pity with commercial units that do not have options available to get thicker insulation because I am sure these units would sell due to the cost savings when running them. The total cost of ownership would be greatly reduced.
Another way to help increase the efficiency of the condenser unit is to increase the air flow around the unit and remove the hot air from the cabinet. A low wattage computer fan installed behind cabinet vents can force the turnover of air in the cabinet the condenser is installed in. The fans can be wired to the main power connection of the fridge electronics and will start to run when the fridge is turned on.
Keep in mind some condenser electronics have a fan power connection and it will only run when the compressor is going. You could connect the low wattage computer fan to this if the total current draw does not exceed the maximum allowable, check the fridge manual for this figure.
Twenty four months later, do we need a second fridge/freezer? No we do not.
We have changed the way we store foods; for example, we use a vacuum bag sealer and use different storage options for fresh produce. We last over a month before fresh produce runs out, but we also find we have a lot less food wastage due to smarter produce choice and menu planning.
Something we found to help reduce fridge cycle time was to keep the fridge full. The best way we have found to do that is; as things are consumed, replace empty spaces with water bottles. Once the water is chilled the cold is then held over reducing the number of cycles needed to hold temperature.
Our fridge also has a holding plate and we have the thermostat set a little colder during the day. Then we switch it off when we go to bed, we have found that the internal fridge temp at the top is still four degrees centigrade or less
in the mornings.
Solar panels are a great way to simplify your charging requirement. There are no moving parts and if you have a good solar regulator it can be set up to output even if you have a secondary charging source like a wind generator in operation at the same time.
The solar regulator is still smart enough to sense when the batteries are charged and then regulate the charge so they are not over-charged. Some wind generator regulators can accept solar panel output which can simplify the total setup.
We upgraded our panels and are very happy with the results. The total output was doubled while keeping with the same size footprint.
This upgrade resulted in seeing an output of up to 22A on good days, not bad considering our old panels were lucky to get 10A in similar conditions.
For the best results install the panels in a permanent, horizontal, shade free location. Do not depend on tilting of the panels, removing shading objects, or controlling boat orientation to increase panel output. In the short term moving and tilting the panels will seem easy work. But it does become a chore and at times when you should be enjoying the sights your thoughts will be filled with moving the solar panels.
Select panels with sufficient rated voltage to overcome the voltage drops due to blocking diodes, operating temperature and probable shading. Make clean solid, corrosion free electrical connections protected with corrosion inhibitor. Do not forget to clean the panel surfaces regularly to keep the panels operating efficiently.
A wind generator is a great addition to supplement the battery recharging. While adding moving parts, they are usually reasonably trouble free and have long life.
The reason we like our wind gen is that it operates 24 hours even in low wind. Instead of the batteries running down during the night, on most occasions we find our batteries are in better shape in the morning than when we went to bed.
In breezy conditions we have found that it is not uncommon to gain significant amp hours during the night. So you may find we do anchor out a little more than some people but we are rewarded with free power from the breeze and there is nothing like waking up with the battery monitor registering one hundred per cent charged.
Our vessel was set up with twin alternators when we first got it. I found the two alternators did not output much more than one due to them sensing each others output.
This twin arrangement may have worked if our house batteries were in two banks with one alternator per bank but they were not. So in the end the alternators were upgraded. We purchased a 190A alternator kit that replaced the drive and water pump pullies and drive belt. We then added a multi-step smart regulator and what a vast improvement over the old system.
The first noticeable improvement was the lack of rubber dust in the motor compartment due to the change from V-belts to a serpentine drive belt. The V-belts had been a high maintenance item requiring tensioning often and replacement every 200 hours.
But the good thing is watching the amp meter sitting at 120 to130 amps at reasonably low rpm, charging the batteries a lot faster on the bulk cycle. The upgrade removed some moving parts and gave us a very efficient way to charge the batteries.
Given our large battery bank size, solar panels, wind generator and our low total energy requirements, it is only once in a blue moon we need to run the engine solely to generate power. I can only remember four occasions in the last eighteen months we ran the motor to top up the batteries and on all four occasions it had been rainy and overcast for a couple of days.
We hate to run the engine and we particularly hate to run the engine to charge our batteries. Aside from the heat, noise and smell, to state the obvious running the engine shortens engine life.
We consider a good anchorage one where, amongst other things, we did not need to run the engine to charge the batteries.
Our approach to electrical balance has been to minimise electrical usage while maximising our storage capabilities. We have installed a large 900Ah battery bank of heavy duty deep cycle, wet cells.
While there is a lot of talk about which batteries are best, all battery types have merits but keep in mind maintenance-free batteries very rarely appear to have the same longevity as the deep cycle wet cells. I also do not like the idea of not being able to check the electrolyte level or being able to do specific gravity testing.
So there you have it in a nutshell how we got the most out of our electrical system. On board power is no different to any other system on your boat, do it right the first time. Remember what initially seems like an inexpensive way to go could very well end up costing you more in the long run as you have to consistently upgrade systems to cope with inefficient products. Minimising your electrical usage may not happen over night, but make a plan and step by step you can get on top of it.
Keep it simple sailor and reduce the stress of consistently worrying if the battery power will make it through ‘til