Electric auxiliary power is not for everyone
Electric power is limited by battery capacity. A lead-acid battery bank that can fit comfortably in a sailboat of 25 to 35 feet will provide about 5 kilowatt hours (kwh) of energy. By comparison, just one gallon of diesel fuel contains the equivalent of about 50 kwh of energy.
Lithium cells that would fit in a typical sailboat could contain perhaps 10 or 15 kwh, but at vastly increased expense and with a significant fire/safety risk. Lead acid batteries remain the only practical way to store electricity on a sailboat.
One way to understand how limited batteries are is by comparing energy density: the amount of available energy per unit of weight. Diesel fuel or gasoline have 460 times as much energy per pound as batteries. To carry the equivalent of 20 gallons (140 lbs) of diesel fuel, you would have to carry 64,000 pounds of batteries.
EA's state-of-the-art PMAC/BLDC motor is 90% efficient, three times as efficient as a typical internal combustion engine, but the bottom line is that the relatively small energy capacity of batteries is a severe limitation on both the power and range of electric auxiliary systems.
This does not mean that battery power is not practical. I have found it to be extremely practical, but it is a question of expectations. We have all become accustomed to using huge amounts of energy, but it is entirely possible to be happy using a tiny fraction of what has become the norm. If you are ready to consider that possibility, then electric auxiliary power may work as well for you as it has for me.
The EA system has been developed in actual use over six seasons in my 29 foot sloop Teal. Over this time it has served me well. I have relied entirely on my solar panel to keep the batteries charged and I have never drained the batteries below half of their capacity.
The key is to use your electric auxiliary power sparingly - to bring your boat to the dock, to negotiate difficult entrances to harbors, to get past the lee of a high headland, to make some progress and maintain steerage way in dead calm conditions, or to go those last few miles to harbor when the wind dies in late afternoon - and to do these things at modest speeds, two or three knots rather than five or six, which greatly improves efficiency. In Teal, using just half of my battery capacity, I can motor at three knots for up to three hours, or at two knots for twelve. Usually, though, I just wait for the wind, and when the wind is blowing and I am in open water, I always sail.
Many people feel the need to rely much more heavily on their auxiliary power. In particular, many people do not sail to windward, especially not when it is blowing, and instead routinely rely on their engines to get where they are going when the wind is against them. Many people set an ambitious cruise schedule, with fixed destinations and arrival times, and when the wind is not ideal - which is most of the time - they motor. If you are one of those people, electric power is not for you. You can get a much more powerful electric motor than the one used in the EA system, but a more powerful motor will demand that much more energy from your batteries. Limited battery capacity will make this extra power entirely impractical.
If you understand this, however, and if you are a competent sailor who prefers to rely primarily on sail, have a seaworthy and weatherly boat, enjoy getting where you are going under sail, and are content to use your auxiliary power sparingly, you will find that electric power has many great advantages over an internal combustion engine.