OK, let me try to pose a question based on my experience. Some years ago, I was sailing in the Med, a few miles off Cap Sicié. Without warning (or a forecast) a mistral kicked up. 20-25 knots, big waves. Two of my crew got seasick and, anyway, I had to get back to Saint-Cyr. So I ran the diesel for about 4 hours, near full throttle. This is the kind of thing that has happened to me many times (for example, in the Northwest Passage, in driving snow). It's less likely here in the San Juans, where forecasts are reliable and there is usually nearby shelter. But anyway, here is the question that others have already asked: what is the range of your boat in dangerous adverse conditions? And please take an even strain. We are all competent, experienced sailors here.
Hi Stefan-
You mean taking an even strain like this:
In my view, electric propulsion is a "boutique" undertaking, to be done for its own sake, not for real-life sailing.
Or this even strained post:
underpowered, finicky, "boutique" propulsion system that only works on smallish lakes? Also, given that the technology is evolving all the time, it is almost guaranteed to be obsolete in a few short years.
Or how about post #25? Does that seem like an even strain and approach to the OPs question?
Now on to my hypothetical, your experience.
In that particular situation with 20-25kts of wind and big waves my little electric motor would struggle mightily. I probably wouldn't even bother running the motor? We've been there in those unforecasted conditions with waterspouts and true tornadoes off the coast of Tampa last year. The only way we could see the biggest twister directly behind our boat was during the flashes of lightning at 4am. It was not a waterspout, but a full take Dorothy to see the wizard tornado. Truly horrifying and frightening conditions when 50 miles off the coast. It never occurred to me to turn on the motor, we sailed our little hearts out in the direction that seemed like safety. Full overpowered sail to make the fastest pace we could away from this growing cell. 6 hours later it was still blowing 30 and we were in 10-15' seas. It was like we got transported to the North Sea or something. Forecast was like 10-15kts. Double handed with two frightened cats. We got chased by waterspouts all day long.
We got caught in a 70 kt knock down in the J44. I went below to check the chartplotter at 50kts of wind. I thought I was going to have run around like a mouse on a wheel. We were double reefed, no headsail and sailed it out. No motor came on that I am aware of.
This same J44 had the motor quit coming into the Beaufort, NC inlet in the dark on an outgoing tide. Probably because of how rough it was coming in. It happens. There were just two of us and we quickly and orderly got the smallest stainless steel anchor, cause you can't carry heavy stuff on a race boat, out of it's silly little locker, attached a nylon tape rode, got to be light, and slowed the boat a little as the skipper ran below and magically got the motor running again. The funniest part, to me, was handing me the nylon strapping material and told to quickly tie a bowline. In the dark, on a piece of nylon strapping and in a serious hurry. You want me to do what??? I did and he promptly threw the anchor overboard. Whelp, I hope I got it right! Not a story we wanted to tell the boat owner.
Maybe none of that is real life sailing, who am I to judge? I'm not here to convince anyone that an electric motor is the proper secondary propulsion for everyone and my apologies if that is coming across. Don't want an electric motor, don't get one. Don't want to deal with dangerous adverse conditions, stick closer to shore. Think LiFePo batteries are not for you, then don't get them. But repeating as fact something you read on the internet is no way to give people advice on a forum.
The OP literally asked about going electric and fair weather sailing on a lake. Who better to offer up thoughts on that than the two guys who literally have electric motors in their boats?
Was that even enough?
Chris