Volvo Penta Active Corrosion Protection System

[CHI]

I have a twin sterndrive boat so have two of these systems to protect both drive legs.

A week ago the Led light on the starboard system was off. Checked power to unit, all ok. Checked 1 amp fuse from direct feed from battery also all ok. Visited boat the other day
only to find that port unit not working. Checked power to unit again with multi meter all ok. Removed fuse from bateery connections for both units. Port unit isolated but stbd unit still live? Assume volvo agent has for some reason bypassed fuse for stbd unit?
However has anyone ever had such a problem with this system i.e. units not working with power going to them. Maybe problem with reference or active anode device under water each side of drive legs?
Any thoughts much appreciated /forums/images/graemlins/mad.gif

 

[enterprise]

I have always wondered how these are wired, are they live all the time or issolated when the 12v circuits are turned off?

If off when 12v side is turned off then there's no protection other than the zincs, we always turn everything off except for the bilge pump which is wired through a fuse direct to the battries when we leave the boat, is this advisable or not, how are yours wired?

 

[CHI]

Correct to have your Bilge pumps wired via a fuse direct to batteries so that they are live when battery switches are off.

The same for the Active corrision system also but through a 1 Amp fuse only as small current draw on S/by mode. /forums/images/graemlins/ooo.gif

 

[VicS]

Been watching this all day but still no suggestions. I cant find out anything very much about the system but I deduce that it monitors the sacrificial system and enhances it via an impressed current from inert electrodes if and when necessary.

Is it possible that the sacrificial anodes have corroded to the point that they are no longer effective?

I note that the system is only suitable for use in salt water, Are you moored in a marina with a substantial fresh water inflow such that the system will not work either directly or because the sacrificial anodes, if zinc, have been rendered ineffective?

I am looking for something common to both installations on the basis that two units are unlikely to fail almost simultaneously and that you have eliminated any deficiency in the power supplies.

Any idea what the monitoring electrodes are?

 

[CHI]

Hi VicS. My boat is moored at Ocean Village , at the top of southampton water, just as you enter the Itchen river.As far as i know still a salt water area. There are no replaceable zinc parts on the reference or active electronic anodes.
I to find it very strange that one should fail and then a week later or so the second unit.

The control boxes within the engine room have four electrical connections. Positive.Negative, Reference anode,Active anode. Using a multi meter power is being supplied to the units.

Both devices were fitted at the same time Feb 2007 , and have been fine up to now. The boat has only been back in the water since june this year. Slight slime and growth at the waterline level but not substantial. I did wonder if fouling could be affecting the operation of the electronic anodes? Maybe a light clean over with my soft boat brush may help?

 

[VicS]

[ QUOTE ]
There are no replaceable zinc parts on the reference or active electronic anodes.

[/ QUOTE ] I meant the normal sacrificial anodes that are part of the sterndrives and would be there normally regardless of the ACP system but if they were OK in June then they are not likely to have wasted away this quickly unless you are suffering some severe level of galvanic corrosion. You have a galvanic isolator in your shore power earth connection?

Fouling of the reference electrodes might be the problem. Any guidance in the owners manual on cleaning them?

 

[neale]

[ QUOTE ]
A week ago the Led light on the starboard system was off.

[/ QUOTE ]

What about the green light?

From memory, the system is only working correctly when they are showing either:

1. A single green light

2. red and green lights together.

If you are only showing a red or are showing no lights at all, the system is not working correctly.

I have had occasions when mine has shown no lights at all and I assumed there was a problem. Next time I looked the lights were on and all seemed fine.

 

[CHI]

HI VicS and Neale
Usual zinc anodes on drive legs ok. I do have a galvanic isolator on the earth wire for the shore power input . Regretably the owners manual from Volvo Penta says nothing about cleaning.
Neale, when working the stbd unit showed green light only, port unit green and red which i understand means port unit supplying current to assist standard zinc anodes.

Firstly stbd unit stopped working ( no lights showing). A week or so port unit the same? Baffleing .

I have left power to units but as yet no luck

 

[CHI]

Have been to boat today and cleaned underwater electronic reference and active anodes. Still no lights showing, so can only assume units have failed as power is still going to units.
Strange they should fail within 7/10 days of each other?
I notice that the latest volvo access. leaflet shows a different type of ref/active anode. Maybe probs with original design?

Seem to remember Motor Boats Monthly were testing the very same units and going to report back later this year.

Anyone know of outcome?

 

[neale]

I guess that would be me then!!! I wrote about fitting them but not sure it will be easy to come back with a definitive result on how they work. After all, how much anode corrosion would I have suffered in the same year had the Active system not been fitted?

What I would say is that even after changing my Ally Props for stainless, the only anode to suffer significant wear was the one around the base of the props. This was down to about 50% after a year in the water. The other anodes were barely touched so I am happy that I am not suffering excessive galvanic corrosion, but how much this is down to the Active anode system is difficult to say.

As mentioned before, I have experienced times when no lights have been lit and then later I have had a light or two.

I am also on a drying mooring which means that although the props and traditional anodes are still in water at low tide, soft mud and pool of water, the active anodes are high and dry. In this state they always show no lights suggesting that if they are not able to detect a requirement to work, they won't. When the tide comes back in and they submerge, the lights come back on again. This is apart from a couple of occasions when they have remained out despite being submerged.

Could it be that something has changed in that 7-10 day period which negates the need for the Active system to be active? Could you try moving the boat to a different location? Have you unplugged shorepower wheras previously it was always plugged in? Has a neighbouring boat moved?

There are lots of variables so if it was me I would monitor over a couple of months and in different locations and if there was no sign of any lights in that time, investigate further.

There should be no problem if they are not working as they only supplement the zinc anodes and presumably you still have these doing their job.

Of course it is possible that yours have gone wrong, but two separate units breaking within 2 weeks of each other does seem a bit unlikely.

 

[CHI]

Hi Neale. Thanks for your reply.
The system has certainly looked after my anodes since being fitted. Before my anodes corroded to approx 50% within 4/5 months. Last year the boat was in for 8/9 months . The annodes were only approx 40% worn away.
Very pleased to see annode wear as this shows they are doing there job. The boat has only been in since june this year. The annodes that i can see on top of the cavatation plate on the DPH legs are only down by about 20/25%.
Nothing has changed around my boat,or the way i use shore power. However i take your point about monitoring over the next few weeks, as i find it very strange that they have both failed within a 10 day time span.

Many thanks again for yours and VicS input.