To have or not have a Hydro generator?
That's a very tricky question, and the answer is that "it depends...".
The short answer is:
- If you are planning on doing night passages fairly often, and hate to run the engine to charge. Then yes, absolutely, get one.
- If you are OK with running the engine to charge 20 minutes every 12 hours. Then you don't need it.
The longer answer:
The Hydro makes it possible to sail around the clock without running the engine for charging. We love that. Look at the picture below, showing the energy we got from our three energy sources (apart from the engine) during our last passage from Turkey to Malta (5 days). At this time of year, the hydro gives more than solar on passage. Different in the height of summer. As you see, our consumption during passage is around 360Ah per day (which include cooking with electricity). This is more than we use at anchor, which is around 200Ah a day. This is because we run all instrumentation, radar 24/7 and navigation lights at night.
Having said all this. I'm not sure hydro is necessary, even though we would replace it if it broke. We've found that we run the engine more often than we think on passage. For instance, as a safety measure and for convenience, we always run the engine when we reef or shake out a reef. We have the leisure furl boom (love it, but that's another discussion), and being short handed it's so easy to put the autopilot on "wind" and have the boat being in irons while Anette and I can concentrate on the sails 100%. This makes us run the engine 10 minutes occasionally. 10 minutes with 2 alternators giving 200A, gives us 33Ah every time to do that.
So, once again. We do not regret getting one, and would replace it if it breaks. But it's nerdy, fairly expensive and needs to be installed and maintained. The break-even point of the investment is too far out to be measured, and having it as a backup for the engine alternator is a weak justification since we have two alternators. So almost impossible to justify from a safety or cost perspective. But very cool, fun and we enjoy seeing the contribution from it.