What do you need for a walk or trip on a yacht or cruiser to guarantee comfort and calm, and not only under the coast, but also away from the coast, except for good weather?
These are electrical appliances familiar to home comfort: TV, electric stove, microwave oven, air conditioner, water heater and much more.
Naturally, the question of their power supply arises; for this, generators were previously installed on boats in the engine compartment. They required a ventilation system, an additional tank, fuel lines, an exhaust system that threw out a little smoke and oil, just at the moment when you decided to rest in complete silence and crystal clear water. And on a yacht or cruiser with outboard motors, where there is virtually no engine room, the use of a generator generally turned into a complex and costly engineering task.
The “puffing machine” is being replaced by alternative and reliable energy sources, lithium batteries with inverters and solar panels for recharging them on a cruise.
Lithium (Li-Ion) batteries are definitely more expensive than lead acid ones, but they work better, last longer, are compact and weigh less. At the same time, the electronic management system «battery management system» (BMS) combines several main battery components and provides, as a rule, five or even six times more discharge-charge cycles over its service life. Due to their low internal resistance, lithium batteries can handle higher charging currents, thereby significantly reducing the time it takes to recover their capacity.
Prices for lithium-ion batteries in relation to capacity continue to fall and, although, at the initial stage, their installation seems to be an expensive investment, slightly more expensive than the cost of an ordinary generator, but this is more than offset by the increased service life and lack of routine maintenance.
If earlier the yacht consumed a lot of electricity for trivial lighting, today, thanks to LED, it has decreased significantly and made it possible to transfer the “load” to other comfortable needs, while reducing energy consumption. It will become possible to take with you equipment with a larger capacity — a coffee machine, a freezer, water purification plants, diving compressors.
Battery management is key during installation. The user interface console provides easy access to critical data and enables remote troubleshooting.
If the yacht has «high-current equipment» on board, for example, a winch, thruster, electric stove, water heater and kettle, it is important to know the maximum discharge parameters, since lithium-ion batteries have a severe limitation.
Since both overvoltage — «overcharge» and undervoltage — «overdischarge» of individual cells are dangerous, as well as their overheating and overheating of the entire battery, an intelligent battery management system (BMS) is installed to control the voltage level of the batteries.
The risk of fire in lithium batteries is worth mentioning. They usually use a flammable electrolyte, and on board a yacht or boat the conditions for charging and operating batteries are often far from ideal. And if the thermal runaway of lead-acid batteries can be stopped by stopping the supply of current, then for lithium batteries this does not work, a burning battery is very difficult to extinguish.
When deciding to install a lithium-ion system yourself on your own boat, we recommend that you consult a professional — at least during the planning stage. The main task of a specialist is to confirm the safety of a product. The case when the cause of thermal runaway became, the cable with a current reset, has already become a classic, as well as the «behavior» of the BMS, which caused an overvoltage in the on-board network, urgently disconnecting the battery and leaving the boat completely without electricity.
To reduce such risks on board, it is necessary to mount batteries in non-combustible housings, correctly place them, ensuring the recommended temperature regime, and equip adequate fire extinguishing systems.
When it comes to recharging batteries, solar power is fast becoming a popular and economical method on boats and yachts. Modern solar cells are highly efficient and lithium batteries make the most of their power.
The photovoltaic or solar «cell» that allows the solar cell to generate energy is made from silicon crystals. By its composition, it can be monocrystalline (consists of one large piece of crystal) or polycrystalline (a placer of small ones). A solar cell contains several of these silicon cells (usually 36 to 40), they are connected in series: the more cells, the more power.
When calculating the solar array for your boat, it is important to realistically estimate how much power you will receive from each solar panel and add a 60% to 80% chance of shading to the peak power when installed. For example, a 50 watt panel rated at 17 volts provides 2.94 amps.
If the planned consumption for charging the batteries is about 30 amperes, then on average 700-800 W solar panels will be required, taking into account the air temperature and efficiency.
In the end, the sun and cloudiness are not in our power, therefore, when choosing panels, it is worth considering that rigid panels with monocrystalline cells are more efficient than semi-flexible panels with polycrystalline cells.
To operate the yacht’s solar panels, in addition to the panels themselves, a charge controller is needed — a device that regulates the battery charge and turns off the solar panel if it is charged or goes into charge support mode.
So the good news for us is that solar energy is getting cheaper every day. And although the cost of solar panels has dropped dramatically over the past decade due to mass production, as is the case with most «marine» products, solar panels specially designed for boats are more expensive than «household» panels due to the simple the fact that the marine environment is complex and harsh.