A few weeks ago the starboard engine wouldn't start and it sounded like a weak battery. I at least learned how the boat manages paralleling the batteries without switches, which is probably improper use of that term. The port engine started and then after a few minutes I was able to start the starboard. This makes sense to me because there is a two alternator/three battery bank battery isolator on board. Once port started, that alternator was feeding enough extra juice to "jump" starboard. Figuring it was a bad battery (it is roughly 3 years old which is all I seem to get here in Florida), I took the battery out to have it tested. It tested good. While normally people would be happy with that result, for us boaters it means that something more expensive is working against us.
I re-installed the battery and tried to start starboard. Slow crank and no start. Start port, wait a bit, and starboard starts fine.
I noticed once the engines were started, the volts were only in the 11.0 range. I had about 13.8 without the engines running. What I found was that the battery isolator is open from A1 to all 3 banks. A1 is most likely starboard. So when the port engine is running, it is feeding all three battery banks, but when starboard is running its alternator can't feed anything.
Diode isolators being pretty old technology, I went in search of something different. DC-DC converters or Argofets seemed to be the way to go. I called the local Victron dealer who put me in touch with The Yacht Rigger. We had a great conversation about what happened and what I'd like to accomplish. He quickly steered me away from Argofets since the ultimate goal is to go full lithium without a generator.
The goals of the project:
1. Run all house loads while underway using the engines. I already need to have two powerful engines running so why have to also have the generator running?
2. Be able to remain comfortable overnight during August in Florida without running any engines.
3. Retain or improve on existing redundancies.
4. A phased approach that doesn't result in any wasted new components, provides as much benefit as early as possible, and minimizes upfront costs.
The initial thinking:
- DC-DC converters now to address the battery isolator issue.
- High output alternator(s).
- Victron LiFePO batteries for house bank.
- Two Victron Multiplus charger/inverters. My requirements would need either two small or one large Multiplus. Two smaller ones are easier to work with.
The Yacht Rigger will be sending me a plan next week with more details. Once this project is fully completed, the generator will essentially be redundant and can be removed. Optionally, we could look at using Quattro instead of Multiplus and keep the generator, but I don't think that really buys anything. Not having a generator would make that space available for either more storage or more batteries.
So far this year is shaping up to have a lot of projects.
We plan to keep the boat for a long time, so spending now will maximize how long we can enjoy the changes. I have no illusion that these projects can be evaluated on any return on investment other than personal enjoyment. My wife and I discussed that if we put this money into this boat then we are not looking to buy another one, even if one of our dream boats were to come available at a price we could afford. Carver was always one of my dream boats anyway. I sure would like to have diesels, but otherwise the 360 is about perfect for us.
If we can get to 20+ hours on the batteries that will be ideal.
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