www.iFourWinns.com

Isn't it always the case that AFTER you take delivery of your new boat is when you see little gremlins here and there.

I have a "fault" condition on one of my galvonic isolators. On my electrical panel - it shows a g. isolator status of "norma" with a green light or "fault" with a red light. Well - one of mine shows red while the other shows green (one for each shore power system. I have a system one and a heat/ac one).

Any idea what causes a fault condition and/or how to go about resolving the issue?

What the heck is a galvonic isolator anyways? I know it has to do something with stray electrical current or something like that - but that's it?

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2008 318 Vista -SOLD, but I am still around!
All Night Long, Seattle WA

Are both legs of your service connected to shore power? If you only have one leg connected and are showing a fault in the one that is not connected this is OK and there is not a problem. The isolator works only on an active shore power circuit. If you are showing a fault on an active circuit there is an issue.

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Previously:
2008 V358/Volvo 5.7 GXi Inboards

Rather than try to quickly explain it, I found the following, thorough primer on galvanic isolation and corrosion on Boat U.S. which is a worthwhile read for any boater, particularly if you have experienced corrosion issues. Re-emphasizing what I said in my last post though, if shore power is not connected it will read as a fault as galvanic isolators only function (and are only needed) when shore power is connected. 'Guest' manufactures the G.A.'s used on Four Winns cruisers (at least in the case of 2008). There are support documents on the Guest site here.


Corrosion and Galvanic Isolators
From Boat U.S. http://www.boatus.com/seaworthy/galvanic/default.asp

Let’s say you dutifully put anodes on your outdrives in early spring, which, in years past, has always been sufficient to protect the outdrives from galvanic corrosion for an entire season. But midway through the season, the anodes are mysteriously gone; dangling screws are the only indication they were ever there. The outdrive is no longer being protected. What happened?

The likely answer has to do with shore power. Galvanic corrosion occurs whenever two dissimilar metals are immersed in electrolyte and the metals are connected by direct contact or by an external wire. In the case above, the external wire was the shore power cord.

The rules governing galvanic corrosion are exactly the same regardless of whether they’re in direct contact or connected by the shore power ground wire. There won’t be corrosion if all of the underwater fittings on all of the boats are made with the same metal — bronze, for example. If, however, there is an imbalance of metals among the boats, which is likely, then galvanic corrosion starts dissolving the least noble metal.

For example: several large cruisers are plugged into shore power on the same pier as an inboard center console with an aluminum outdrive. The cruisers all have bronze and stainless steel fittings under the water (rudder, shafts, props) and no anodes. If there is an anode on the center console’s outdrive, the anode will begin to quickly waste away. As the anode is dissolved, the least noble metal on any of the connected boats — in this case, the center console’s outdrive — will begin corroding.

Another possible situation: Several boats with aluminum outdrives are plugged into AC power on the same pier. Some are protected with anodes and some aren’t. Initially, outdrives that aren’t protected will be protected by the other boats’ anodes. Conversely, the protected boats will find their anodes are dissolving quicker. All it takes is one boat that isn’t protected to affect other boats that have less noble underwater fittings. As the anodes are worn down, all of the boats’ outdrives will be vulnerable to galvanic corrosion.

The source of the corrosion isn’t always apparent and there is no instant fix, short of constantly replacing your boat’s anodes. If you unplug the shore power cord, you (and the boat) won’t have the benefit of AC appliances like battery chargers and refrigeration. Another quick fix — interrupting the circuit by cutting the green grounding wire on your boat — means the AC electrical system will no longer be grounded and anyone in the water near your boat runs the considerable risk of being electrocuted by stray AC current. Even a few milliamps of AC electricity in the water can paralyze a swimmer’s muscles, causing him or her to drown.

The most common way to reliably and safely interrupt the circuit is to install a galvanic isolator. Galvanic isolators attach to the green grounding wire to limit galvanic current flow (up to about 1.2 volts) between neighboring boats while also allowing dangerous AC current to safely pass through to the ground on shore. The most efficient galvanic isolators have a capacitor, which allow the isolator to continue to block galvanic DC current flow even if there is a small AC current leakage on the ground wire.

Protection can also be provided, typically on larger boats and aluminum boats, with an isolation transformer. The latter is much more expensive but will also protect the boat’s AC system from shoreside power surges.

Isolators are rated in two sizes: 30- amp and 50-amp. A boat with a 30-amp cable needs a 30-amp isolator. A boat with a 50-amp cable needs a 50-amp isolator. If a boat has two shore power inputs, it needs separate 30-amp isolators for each input.

Just when all of this galvanic corrosion business starts to make sense, there may be instances involving corrosion that defy logic, such as when a more noble metal becomes severely corroded, leaving a less noble metal unharmed. This is likely the effect of stray current corrosion, which can drive normally cathodic metals to become anodic.

_________________
Previously:
2008 V358/Volvo 5.7 GXi Inboards

Thanks Sierra.

I did track down that the 318 has Guest units on board -- They are Guest 2433's to be precise.

I also found this documentation on them: http://spirit.the-millers.org/Guest-2433-P.pdf

It looks like the solid red light means a failure somewhere in the unit. I'm going to validate that the shore power isn't affecting this - then I guess it'll be replaced under warranty. These are not fused nor can they be reset.

Fortunately, the other unit is working fine and shows Green -- there is also an activity (blinking) if the unit detects a large amount of current and what not.

I feel safe as long as I can get this fixed in the next couple of weeks.

I didn't realize it's a passive system -- ie, there's nothing I can do to turn it on/off or anything.

The boat has power to it from the shore power system -- it still reads the corect AC volate on the panel even when I shut off the heat/ac panel completely.

Hopefully it's just a unit that busted... we'll see.

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2008 318 Vista -SOLD, but I am still around!
All Night Long, Seattle WA

At least you can see the light panel on your GI unit. The one on my '03 V298 is mounted on the port sidewall of the engine compartment almost above floor level and the lights are pointing up the hull side into the dead space (this would be located under or behind the wet bar). The only way I can catch a glimpse of the indicator lights is with a mirror on a stick. The harnesses to it are pretty tight and secure so remounting it would be problematic at best, requiring much rewiring. Anyone else have this issue?

By the way, CC, Really nice pics and narrative on the other thread re: your recent launch. I'm thoroughly jealous as I look out the window at nearly 4 feet of Lake Michigan that has been crystalized and redeposited on my deck at the house!

Happy Boating!