With no auxiliary generator on board, we need additional power to reduce the amount of time that we would otherwise need to run the engine to maintain adequate charge across our battery banks. When we bought Arkyla, she was originally equipped only with a Solarware semi-flexible 100w folding panel that could be fixed to the bimini canvas. There were two main issues with this set up; 100 watts was insufficient to meet our anticipated energy requirements, and that during offshore passages it may not be wise to keep the bimini rigged in some weather conditions.
In 2019, we commissioned the team at Greenham Regis in Lymington to design and install a new system; our brief to them was to deliver a solution that will provide for the majority of our anticipated near-medium term cruising energy needs (basically, cruising the Med and then an Atlantic crossing to explore the Caribbean), without resorting to engine alternator-generated power, whilst retaining the clean lines of the boat and without making the stern look like the proverbial Christmas tree. Installation work was interrupted by the impacts of COVID, but by end-July 2020 we finally had a working system. We now have a low-profile gantry and pole with a setup that includes:
Marlec Rutland 1200 wind generator.
2x 100 watt Leading Edge professional monocrystalline 12v solar panels.
Option to add the feed from the original Sunware 100 watt Textile panels when mounted on bimini.
Wind/solar MPPT charger for gantry-mounted kit, and separate solar charger for the bimini panels (replacing original Fox-360 control)
We haven't yet had time to fully test the setup to confirm that it meets all our energy equation needs whilst on passage or at anchor. However, the early indications from observing both the solar panel and wind generator outputs so far are that even this limited setup should provide for most of our needs. In association with the power generation upgrades, we have also replaced all of the halogen interior and navigation lights with low-power LED alternatives - this has significantly reduced the draw on our banks.
The Rutland 1200: We have, so far, been very impressed with the energy outputs, ease of use (we have the optional remote unit installed which allows you to monitor individual outputs of, and to cut the feeds from, either/both the gantry-mounted wind and solar units), and quietness of the generator. We originally purchased a Leading Edge design wind generator but this produced little power, resonated wildly, made excessive fan noise with accompanied 'howling' and could not be left in a 'break' condition unless the blades were physically lashed; the Rutland unit has none of these problems, though occasionally we do get some hull resonance heard but only in the aft cabin.
Leading Edge 100 Watt Panels: Whilst we may have been less than impressed with the LE wind generator we originally had installed, we have been very happy with their professional monocrystalline 12v solar panels. The marketing claims that the Sunpower Corp cells used in the DC-Solar range are the most efficient currently available on the market (at a quoted 21.5% cell efficiency); certainly we can confirm that the rigid glass-fronted panels, mounted within a very sturdy anodised aluminium frame, pump out the amperes even during significantly cloudy conditions. My original fears of under-powering our solar set up in favour of maintaining a low-obtrusive footprint on the boat seem to be unfounded and, with the addition of the bimini-mounted units hooked up when at anchor, we are fairly confident that we will meet our basic energy requirements.
SunWare 100 Watt Textile Solar Panel: This is the panel that we inherited when we purchased Arkyla; the unit is effectively two hinged panels that clip to studs on the bimini. Each panel operates independently so if one panel is shaded the other will still operate at full capacity.
We inherited a somewhat Heath-Robinsonesque battery system when we bought the yacht that differed significantly from the all-AGM set-up when the boat was delivered new from the Regina yard. The bank, located in the centre of the boat close to the engine bay, consisted of 1x 75AH sealed Lead Acid starter battery (on its own circuit), and a domestic bank of 4x 100AH sealed Lead Acid and 1x 120AH Lead Acid batteries; we assume that the 'odd' 120AH unit was added to power the bow thruster.
We have now added a dedicated 125AH AGM battery, located in the bow, to power the thruster and windlass. This is connected to the main domestic battery bank via a DC-to-DC charger (also located in the bow); with this configuration, it does not matter that we are mixing different battery types/capacities.
In 2021 we replaced the Balmar 150-amp alternator and all of the original lead acid batteries. The house bank now consists of 5x 130AH AGM batteries giving a total usable reserve (at assumed 50% draw capacity) of 325AH. The starter battery has also been replaced with a single 130AH AGM unit.
Charging from the main engine has been uprated by fitting a 150A Balmar alternator.