It's a secret

So...work on the rebuild progresses. The inverter is fixed in place and all of the 4/0 cable is routed; that would be just shy of 200 feet worth. The batteries are in place, sharing electrons through 22 cables hooking the house bank together and leading to the remote battery switches. No big red twist switches on this boat, just two little push buttons to bring the batteries on line. (Very much like the master switch in an aircraft electrical system.) There are two because the hot and ground circuits from the batteries to the inverter each consist of two runs of 4/0 cable connected in parallel; part of the reason there is nearly 200 feet worth. It isn't that there is that much current being carried, though with the air conditioning running the inverter will be pulling around 180 amps out of the batteries. No, the issue is that current has to run slightly more than 40 feet, the system couldn't take the current loss of a smaller cable. (Also, too much smaller and those puppies would glow like toaster wires under a full load.)

An additional issue is the lack of space in the bow of the boat for a battery to drive the bow thruster, so it is wired to the ship's batteries with its own run of 4/0 cable; the rest of the reason there is nearly 200 feet worth. All this wire running required adding 5 different conduits below the floor and through the starboard engine compartment. One of the runs, the only one needing room for all 6 4/0 cables, two 2 gauge cables for the windlass, and some 120 volt AC lines, is 4 inches in diameter. It is the biggest conduit I have ever seen in a boat, let alone installed myself.

Included in all this wiring is a network that lets the inverter / charger, information center, and two shunt / power sources to chat with each and give out information on every unit in the system. Since it will eventually be hooked up to a laptop for programming, it might also remind you of your anniversary, start the coffee in the morning, and plot a course to the moon. But, while routing all of this networking wiring, a problem popped up. The wiring , which is all pre-fabricated and supplied with the various units, simply would not plug into the inverter / charger. Weird, since that thing is the heart and soul of the entire system. Searching through the piles of boxes didn't unearth some missing patch cord, nor did a careful review of the manuals, installation instructions, and diagrams, (all of which are now very familiar territory) shed any light on the problem. The manuals specifically state that all of the networking is done through through standard, and identical, cables. Various diagrams showed the inverter / charger daisy chained in just like every other unit, all of which accepted the standard cables just fine.

After nearly and hour of puzzling through various attempts to figure out what I was doing wrong it seemed prudent to throw in the towel and call in some help. Which, in this case, meant calling in outside help since no one in the yard has any more experience with this system than I do. It is relatively new to the market, and I feared that the appropriate level of product support would prove difficult to unearth. Fortunately, it only took two phone calls to have an honest-to-goodness system tech on the other end of the line, one who instantly went to the heart of my problem.

“Do you have the inverter combi interface?”

“Sure,” I replied. “Well, we should since we ordered it as a complete system though, I don't recall seeing anything called an “inverter combi interface” or putting any such a thing into the boat. In fact, I don't recall seeing any reference to an inverter combi interface in any of the paperwork I have, nor does it appear in any of the diagrams.”

“I know,” came the reply. “It isn't referenced in the paperwork anywhere. You need to get one though, otherwise you can't wire the inverter combi into the network.”

Okay then...

Apparently the need for an inverter combi interface unit is a closely held secret, one shared only with the initiated who have the special decoder ring which leads to the proper phone number. Once connected to the inner circle one then has to invoke the proper spell by asking the right question. Only then one will be blessed with the knowledge of the “inverter combi interface unit” and thus reach the Nineveh of a functioning system that will remind one of anniversaries, start the coffee, and plot a course to the moon. Of course someone also has to write a check for just less than $300...not including shipping.

So, don't tell anyone that I told you.