How to Prevent Marine Corrosion

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Corrosion CAUSE prevented, permanently

8-year guarantee, warranty and diagnostic support.

Marine electrolysis corrosion prevention with free support.  For a minimum of 8 years. No reason money-back guarantee.

Reading time to a point where we can take responsibility, one minute. Click here.

8-year free guarantee, warranty and (link) diagnosis support:  We will either prevent all the stray current that is the ONLY CAUSE of marine electrolysis corrosion or pay you back your purchase cost of SeaBis Master. How to Prevent Marine Corrosion must be complied with. Guarantee here.

Busy? There is no need to read any further.  

We will, step by step, guide you or another through prevention of the stray current that is the ONLY  CAUSE of 97 % of all corrosion.  Email;

Complete contact details here and password is 8.

Table of Contents

Suggested reading:

Marine Electrolysis Corrosion CAUSE Prevention here.

Marine Stray Current Prevention 100% here.

How to Prevent Marine Corrosion (stray current / electrolysis).

SeaBis Master must be used with How to Prevent Marine Corrosion instructions.

We will support you.  Email:

Printed How to Prevent Corrosion instructions with causes and their prevention, and a generic wiring diagram are included with SeaBis Master System. 

SeaBis Master System with How to Prevent Marine Corrosion instructions:

Briefly.  Connect SeaBis Master.  If other than Normal (green) LED is on, then switch off or disconnect wires until you get a Normal.  The last wire you switched off was the cause.  Reconnect the remainder.  See which has no power, and you will know the cause.

Free training and diagnostic support are provided with the purchase of each SeaBis Master for a minimum of 8 years: Email

  • Proof we are correct, (external reference) DC (batteries) causes corrosion, not AC (mains shore power): Wikipedia Note apparatus leads for DC are red and black. If in doubt, check with a licensed electrician before performing any work on your system.
Technical explanation (in plain language)

Use of our SeaBis Master System is essential in detection and preventing the source of stray current.  Stray current is 97% of all corrosion.  The SeaBis Master System identifies and prevents the CAUSE of stray current.  No additional coating/s, plating, moving parts or through hull or other penetration.  We prevent the CAUSE, permanently.

Rust (oxidisation with atmospheric stray current), stray current (electrolytic action on your own boat), marina corrosion (caused by migration of current from surrounding boats), galvanic corrosion (bimetallic corrosion) are all common terms.

Stray current commonly vastly accelerates rust. On a million to one ratio. So, prevent stray current first.

Galvanic corrosion is caused by two different metals being in near touching proximity in a conductor, such as water.  Galvanic is at least a thousand times slower than stray current corrosion.  Anodes, when stray current corrosion is prevented, will greatly reduce galvanic corrosion.  Anodes should then last 3 to 4 years.  If they don’t then stray current is probably the cause.

Stray Current Corrosion before SeaBis Master System and How to Prevent Marine Corrosion:

None are caused by Galvanic (different metals, nearly touching) corrosion.

After SeaBis Master System and How to Prevent Marine Corrosion.  One year submerged. No corrosion:

After SeaBis. Antifouling works as designed.
After SeaBis. A year submerged. Marine electrolysis corrosion prevention identifies then prevents the stray current that is the only CAUSE. Permanently. Antifouling works as designed.
After SeaBis. No stray currents. Antifouling works as designed.
After SeaBis. Underwater view. A year submerged. Marine electrolysis corrosion prevention stops ALL stray current. Antifouling works as designed.
We can’t stress it more:  Stray current corrosion is caused by wiring or equipment defects onboard your vessel.  Your own power is generating the stray current that is the ONLY cause of electrolysis corrosion.  Using your power.  At your expense. 

Corroding those boats and installations around you within at least 150 metres. Via air and water. 

Including electrocution of persons who touch the water.

Electrolysis corrosion is 97% of ALL CORROSION.  The SeaBis Master System prevents electrolysis corrosion, CAUSE, permanently. 

“I witness stray current destroy propellers and boat hull in 10 days, many times every year”

The cause is stray current flowing from your vessel to the Earth.  Here is where our SeaBis Master System pays for itself, very quickly.  SeaBis Master System helps locate the source of stray current (the source of your corrosion).  Saving you many thousand dollars in ongoing or, possible emergency repairs.

Stray current thru electrolytic action creates corrosion. So, the original cause of this form of marine corrosion is your vessel creating its own stray current.  If you need additional clarification, please feel free to contact us. 


How to Prevent Marine Corrosion Instructions.

How to use the SeaBis Master:

This simplified method applies to 95% of vessels.

SeaBis Master will detect and indicate DC (batteries) stray current, battery caused corrosion.  SeaBis Master System will help you to correct the cause so your anodes will work as designed and last many years longer. So galvanic corrosion is reduced.

The SeaBis Master System identifies the source of your stray current.  It can then be prevented. Stray current – the electrical energy generated by your vessel that is causing your stray current corrosion.

Using our SeaBis Master with battery clips as a portable will detect permanent causes of stray current corrosion.  However, every boat or yacht will experience intermittent stray current within a year.  Caused by new or replacement equipment or wear and use. If not monitored by SeaBis this stray current corrosion will soon become visible.

Permanent installation will provide an ongoing detector for all causes, permanently.  Let SeaBis do its job! You will be rewarded with advanced warning of any stray current before it becomes corrosion.

Intermittent connection may cause stray current to go unnoticed and, reduce our Guarantee and Warranty from the normal 8 years to 10 days – the time it takes for monitored stray current corrosion to become visible.

We strongly recommend permanent installation of SeaBis Master! Then you will comply with ABYC Wiring Rules and How to Prevent Marine Corrosion. 

Then stray current cause is immediately detected and galvanic corrosion easy to control. The SeaBis Master will operate correctly at sea, dry dock or, on the hard (out of water slip).


How to Prevent Marine Corrosion Instructions.


Unplug all AC shore power.  That will make your diagnosis much simpler.  Later we will test the shore power when your entire boat or yacht is proven Normal by SeaBis Master.

First connect SeaBis Master to the battery bank being diagnosed (all battery banks must be tested by SeaBis Master).  Connect blue lead to battery negative (-), the brown lead to battery positive (+) and green & yellow wire – current sense to a clean unpainted engine body or hull metal.  Do not connect to AC (alternating current) shore power mains power supply or, your Inverter output – AC kills electronics.

*** If AC Only flashes more than 3 times, at one occasion, the cause MUST be corrected immediately. Failure to do so puts your electronics at risk and damages your batteries. If needed contact us:

All work on mains power, 110, 220, 240 volts, all mains power, must be done by a qualified A Class Electrician.  He must be onboard and issue a Certificate of Compliance.

SeaBis Master must be permanently installed and, our How to Prevent Marine Corrosion instructions fully complied with, for our 8-year Guarantee or Warranty to be valid.   If you are unsure on how to permanently install your new SeaBis Master a certified “MARINE” electrician is recommended.  

Failure to fully comply will limit our Guarantee and Warranty to 10 days.  That’s the time it takes for undetected stray current to cause corrosion you can see.  At 10 or more un-monitored days, while power is applied, the monitoring time will allow stray current corrosion to occur without warning.

Equipment you cannot turn off such as bilge pumps are addressed separately. This minimises the risk while you are not onboard. Contact us for more detail.


Diagnostic Procedure to locate specific equipment causing stray current corrosion:

The first step in eliminating stray current is to identify the cause by finding the electrical connections that are causing current to flow through metals in contact with damp or water causing stray current corrosion causing a Red LED (serious or critical) to light.  Always work to get a Normal (Green) LED first! 

When a Normal (Green) LED is lit there is no stray current and, we must first get to this stage.

We do this by disconnecting electrical connections which include those that allow unwanted current to flow until a Normal LED is obtained. 

As follows:

Disconnect shore power.  DO NOT disconnect main battery negative or positive feed to your boat’s distribution panel. 

Disconnect all black (-) wires, labelling and insulating them as you go – to prevent shorting, at the brass strip that joins all the battery negatives (-) together (label each them separately) until you get Normal.  The connection removed last was causing your DC stray current.  Leave that lead disconnected and label it “DC stray current”. 

Momentarily connect all others; one at a time, leaving disconnected all that show DC stray current. 

Permanently re-connect all those that do not cause stray current.

On completion you will have one or more negative (-) wires disconnected.  They are the ones causing stray current.

Now see what onboard has no power and you will know the cause (source) of your stray current. 

Follow our How to Prevent Marine Corrosion instruction’s to remove the cause.

Important: DO NOT disconnect a single battery terminal leaving the other battery terminal of the same battery or bank connected, you will likely cause an imbalance in the circuit and cause stray current.  Disconnect both battery terminals or neither.


1:  It is common for more than one fault to cause stray current (causes are connected “in parallel”).  If we call these faults A, B and C, with any connected we are showing a RED (Serious or Critical) LED then disconnecting only one or two of A, B and C and leaving one connected will not result in a Green (Normal) LED with stray current still flowing, and we will not know that we have already disconnected the two wires causing problems. 

All connections that allow a stray current to flow must be disconnected before a Normal LED lights.


Expanded instructions:

1:  If the battery negative LED light (right side) illuminates a decision as to time interval for repair can be made according to its indicated severity.

2:  If the battery positive, Caution, Serious or Critical (left side) LED illuminates then there is a DC stray current defect in the wiring of your electrical or, electronic equipment, the corresponding fuses are possibly bypassed by the fault, resulting in the wiring becoming the fuse therefore becoming a fire risk.  These faults must be repaired urgently. 

Partial battery disconnection can also cause this.  ***Especially if you disconnect the battery negative main supply for the circuit being tested***.

N.B. While the battery positive “Caution” illuminates its often a result of a far more important, corrosive intermittent defect.  Email me:


LED explanations:

Normal:  Stray current is at a very low level and can never cause corrosion.

N.B.  If both Normal alternately illuminate the stray current is changing direction because of excessive AC.  AC cannot cause corrosion.  However, it will damage batteries and electronics.  Observe AC Only.

Caution on battery negative (-):  A very small current is causing stray current corrosion.  The corrosion may be barely visible in one year. There is a risk a fault may become serious.

Caution on battery positive (+) is potentially dangerous: 

Particularly if you have 12 and 24 volts in the same system.  There is DC stray current flowing from battery positive (+) through the hull and / or the engine. 

Warning: The cause is failing insulation; carbon build up or moisture touching a battery positive terminal and hull and / or engine.

If cause is failing insulation, then the fuse may be bypassed so making the wiring the fuse and so a fire risk.

Stray current may be flowing in 2 directions, often intermittently making for far more serious corrosion.  Particularly if the AC Only and other than Normal flashes.

Serious:  Stray current is causing corrosion.  This corrosion will be visible within 6 months.

Critical:  The upper measurable limit of DC stray current is causing corrosion NOW!  The corrosion will be easily visible in 3 months.  Repair this problem immediately!

AC Only:  AC current exceeds a very liberal specification.  It will not cause corrosion but will at the very least half the life of your batteries and possibly damage your electronics.  It indicates a possible reversal of Active, Neutral or Earth.  That creates a risk to your life.

AC current reverses direction every one hundredth of a second so charges then discharges your battery every one hundredth of a second. The risk of electrocution is increased – get a Certified AC Electrician to talk to us and repair the cause without delay.

If you get inconsistent (intermittent) LED’s depending where you connect the current sense wire (green/yellow) the coating on the metal is causing resistance to current sensing detection circuit and needs to be filed off and cleaned free of all oil, grease, paint, deposit or corrosion to clean bare metal, then reconnected.

A Qualified Technician or Certified Electrician is rarely necessary.  Our SeaBis Master System Traffic Light design is easy to follow. 

However, we will talk you and / or your Technician or Electrician through diagnosis.  Our training course and diagnostic advice is supplied free to all SeaBis Master System purchasers.

How to Prevent Marine Corrosion:

**** Always work from a Normal – (Green) LED. ****


Extending all three (3) SeaBis Master wires:

All 3 wires can be extended up to 1,500 meters.  Use good quality water resistant crimp connectors, or solder wiring joints then insulate with “Silicone cored” Heat Shrink or Scotch 23 self-amalgamating rubber tape.

Reason:   No current drop or leakage to the air.  The air is a conductor when air or electrical connections are not absolutely dry.


Engine / Generator decision:

Is the engine or generator metal body connected to battery negative (-)? 

Can you see the (black) battery negative (-) connected to engine body? 

If so, disconnect it and confirm by connecting your SeaBis Master to the engine or generator battery with current sense (green/yellow) wire connected to the metal body.  You should get a Normal.  If not, then there is something else connected to battery negative to metal body.

Next step is to leave only the House (all none engine) batteries connected.  Now proceed with House Repairs.

House (none engine) repair:

*** Should the House batteries indicate other than Normal then to stop confusion, remove the battery positive and negative from the engine system prior to working on the House. 

It may be necessary to run temporary wiring from the battery negative (-) to the house. ***

1:  Connect your new SeaBis Master to the House battery bank and sense wire (green and yellow) to metal hull or engine.

2:  Visually check if battery negative (-) is connected to the (metal) hull.  Connecting battery negative (-) to hull will cause stray current. 

Correct the cause by disconnecting wires and equipment from the hull until your SeaBis Master indicates Normal then connect the disconnected wires directly to the battery negative (-) terminal.


This second method is absolute:

1:  Follow Diagnostic Procedure at the beginning but in PAIRS.


Shore Power / ICCP testing:

When the entire vessel DC system is proven Normal by your SeaBis Master:

To test AC shore power / ICCP, plug it in.  SeaBis will test shore power / ICCP.  Any change from Normal is caused by shore power / ICCP.


Engine or Generator – Are they Isolated / insulated correctly?

1:  When the House is totally and permanently Normal on your SeaBis Master, then complete the following for the Engine and / or Generator:Connect SeaBis Master to the engine battery and sense wire (green & yellow) to engine metal body.

2:  If SeaBis indicates Normal then the engine or generator is isolated – all equipment terminals are insulated from their metal body.  Excellent.  Keep engine or generator monitored by its own SeaBis Master, as moisture, carbon dust and failing insulation accumulate causing stray current.  Then your SeaBis Master will provide an immediate warning WHEN a fault develops.

3:  If SeaBis indicates other than Normal:  Visually check the engine body battery negative (-):

 If there is no insulator under the battery negative (-) at the body of the engine then the engine cannot be isolated.  Repeat this with the alternator and / or generator and senders (sensors).  Proceed to Engine Repair Instructions.

4:  Engine battery negative (-) connection:

In a recreational boat or yacht, we use a manual switch or automatic solenoid in series with the battery negative (-) to the engine or hull thus eliminating 97% of stray current.

Procedure follows:

Engine Repair Instructions.

Your first decision!

1:  Is the vessel for recreational use with engine ON cumulative hours less than 200 per year?

If yes, as are most, then a manual or automatic switch (solenoid / relay switch) in series with the battery negative (-) to the engine body), will correct 97% of DC stray current; 

Our calculations are based on 200 hours divided by 8400 hours in a year = 3%. Check starter motor RMS current (see Compliance Plate on Starter) does not exceed switch / contact rating.

2:  While the engine is not running and that switch is OFF, it will prevent all stray current caused by the engine. 

3:  While the engine is on or running and the switch is ON, your SeaBis Master will flash Critical as stray current flows – for 3% of the time. So, you will receive 3% of stray current. This is within calculated safe limits.

4:  The remainder of the vessel is left permanently connected so you can use the House equipment, without stray current corrosion as it is proven free of stray current using your SeaBis Master.

If engine ON hours exceed 200 per year, then we consider this Commercial use.

See Commercial use engines, below.  If you have difficulty contact me:

Automatic or manual switching of battery negative (-) and / or positive (+):

Automatic method uses a solenoid switch / or relay:

1:  Approved solenoids are available at SeaBis on our “Buy” page.

2:  The principle is to cease using the hull or engine body as a permanent connection and use the solenoid to switch battery negative (-).  The solenoid switch will provide battery negative (-) to the starter motor / alternator / generator / winch connection only when in actual use.  Stray current will occur only when the solenoid is ON (tech speak Closed) that is when that equipment is actually turned ON. (See acceptable measured limits earlier in this document)

3:  Multiple solenoids can be used to switch negative (-) and positive (+) and heavy loads from Start/Run/On switch. Select your systems applicable 12 or 24 volt solenoid model.

4:  Solenoids do not get forgotten so are the preferred (advised) method for non-commercial use of less than 200 CUMULATIVE circuit ON hours per year, so we consider this domestic pleasure use.


Manual Switch Method:

Take care:  If you forget to Open (switch off) just once then stray current corrosion will occur.  Your SeaBis Master, permanently installed, will flash red Critical.

The new switch RMS rating must be at least equal to or greater than the main battery positive (+) switch, usually 200 amps RMS. It is wired in series with the battery negative (-) lead. 

Some boaters prefer to use a Double Pole switch so both the battery negative (-) and positive (+) are OFF (Open Circuit) using only one switch.  There is a risk and a common cause of stray current, the switch gets forgotten


With new switch in OFF (tech speak Open) only the engine cooling water to the sea path remains. Your SeaBis Master will indicate Normal or Caution because the engine cooling water to engine body is an electrical earth ground. When broken at the engine, it only has a partial path to the sea. This path is prevented from becoming completed by the newly installed switch.

Caution is an extremely low level of stray current and is often caused by the engine cooling system.  There is a risk a fault may become serious.  In the absence of your SeaBis Master System, it is possible for the engine cooling system connection with the sea to cause Critical stray current corrosion.

With the new switch ON, the engine runs as normal.  Stray current flows and your SeaBis Master will flash Critical, but the effect of this stray current is minimised because the new switch is turned OFF at least 97% of the time.

Procedure to identify and repair the cause of stray current where engine ON hours exceed 200 per year – (Commercial use vessels)

The only difference is all causes of stray current, where design is the cause, are switched OFF.

Sensors, correctly insulated, available at:

A.S.A.P. Supplies in U.K. link: ASAP-UK sells Teddington senders (sensors) and switches proven correctly to insulate the battery negative (-) for the engine.   To get this thread exactly correct here is a link (click here) for the Thread Gauge from Fastener Retailer.

Starter Motors and Alternators can be insulated:

Can often be fitted with an insulator to battery negative (-), in the body, by an Automotive Re-winder. 

Insulating / waterproofing:

Use Scotch 23 Self Amalgamating rubber tape to waterproof all joins and crimps or use solder connections with silicon core heat shrink tubing (recommended even over heat shrinkable crimp connectors).

If you have any difficulty at any point, we will talk you through entire vessel full insulation.  Any difficulties contact me: email

How many SeaBis do I need?

ALL batteries and DC power, without a SeaBis Master, create undetected DC stray current that causes corrosion. Monitor them all!

1: One SeaBis Master will help you to correct all permanent causes of stray current. It may be fitted with battery clips and moved between battery banks. However, SeaBis monitors the battery bank it is connected to. So, it may not detect intermittent or new causes and stray current may occur, sometimes within 10 days.  Multiple battery banks may be switched in parallel by battery switches “Both” or “Emergency”.  Then SeaBis will monitor them all.

2: Multiple battery banks that cannot be switched in parallel (as one battery):

To comply with “How to Prevent Corrosion” and validate our guarantee and warranty a SeaBis Master must be permanently installed.


Every battery is a source of stray current – 24 hours a day, ALL year. So permanently installing one SeaBis Master per *independent battery bank / DC source (including regulators, reducers and DC generated from AC). Then you will comply with ABYC Wiring Rules, and SeaBis – How to Prevent Corrosion.

*Independent – All DC sources must be monitored by a SeaBis Master more than 97% of the time when power is applied – (see next paragraph) to correct 97% of all stray current causes. Allow your SeaBis Masters to do their jobs by permanently connecting to every source!

Time away from your vessel is excluded as we will take steps to ensure there is no stray current – see How to Prevent Corrosion.

3: Equipment you cannot turn off is treated separately. This absolutely minimises risk.

4: Remember: If you monitor any battery bank less than 97% of its total time, there is a vastly increased risk of stray current without your knowledge.

SeaBis is a sophisticated current meter – it can only monitor the circuit it is connected to. So, if you breach the 97% for more than 10 cumulative days in a year there is inadequate monitoring time to ensure stray current will be detected and you can correct the cause. Under these circumstances our guarantee and warranty are limited to 10 days, as that is the time it takes for stray current damage to be visible. Stray current will occur without your knowledge as your SeaBis Master will be monitoring elsewhere. Allow your SeaBis Master to do its job by permanently connecting to every source!

5: Obviously if you do not monitor a battery for longer than the time (10 cumulative days in a year) to prevent it from creating stray current corrosion the chance of corrosion occurring is vastly increased.

Some people insist on using only one SeaBis Master with battery clips as their only protection – they know the risk.

Sometimes they get away with it. Sometimes they pay massive repair costs. I witness repair costs at 95% of vessels value, twice a year. It is your choice, as are the consequences, you are the owner…

If you have a 12 and 24 volts system then ALL DC sources must each be permanently fitted with SeaBis Master – there will be 3 times the stray current capability.  Failure to comply will void your warranty and guarantee.

6: As always, we will support you. However, for our 8-year guarantee and warranty to remain valid, you must comply with our How to Prevent Corrosion, supplied with your new SeaBis Master. Then the causes of stray current will be effectively prevented. 

Generic Wiring Diagram is supplied with SeaBis Master System.

1:  To correct the cause of stray current; all metal – body of engine or hull or any metal that can get damp to wet – are insulated from battery negative (-) and positive (+).  Then your boat complies with ABYC Wiring Rules and How to Prevent Corrosion.

2:  At the battery, in series with battery negative (-), fit 200 amp RMS continuous rated solenoid / switch or relay.  All terminals must be insulated from the metal body. Solenoids are available on our SeaBis “Buy Now” page.

3:  It is absolutely imperative to use SeaBis, to ensure that all the remainder of the boat or yacht is proven to have no stray current, permanently.  SeaBis must indicate Normal permanently.

Allow your SeaBis Master to do its job:  The following full details must be complied with to make your Guarantee or Warranty effective:

Internationally recognised wiring rules are available at: ABYC Wiring Rules

SeaBis installation, full details:

1:  To ensure that every existing and future cause is indicated and corrected, one SeaBis Master must be permanently connected to every independent (non parallel) battery and source of DC.

Important facts:

1:  Fact: Blockers are very unlikely to provide any protection: Additionally, they increase the risk of electrocution.

Note that “Electrolysis / Stray Current” (Galvanic) Blocker only blocks the shore Earth.  It does not block the shore Neutral or Active or the far more common path – the sea.  That is not acceptable. 

Galvanic “isolators” (a little respect please) are commonly only a diode bridge, with value of $1.00.  It has no safety capacitor.  There is only one to our knowledge on the market that has a safety capacitor and UL rating and that is manufactured by Mercury Marine in the USA, its intent is to protect the boats AC system from shore return spikes, not corrosion.

Without the capacitor, most galvanic isolation regardless of cost, are one time protection when their diodes fuse closed during a fault.

The SeaBis Master System with How to Prevent Marine Corrosion is 100% successful.  That is why SeaBis has an 8-year money back guarantee and Blockers do not. 

2:  Fact:  Stray current from every DC source (battery / generator / reducer / regulator or mains sourced DC),without the SeaBis System, causes stray current corrosion to exist.  When there is no stray current, there can be no stray current corrosion. 

Current is the cause, not voltage!  Your SeaBis Master measures current.  The cause is prevented by following our instructions, completely.

3:  Fact:  AC (mains or shore power) cannot cause the (DC) stray current that causes stray current corrosion. It reverses direction every ½ Hertz or Cycle. 

So, IF it takes off a particle in first ½ Hertz if will put it back on in the second ½ Hertz. It is impossible for AC to cause DC stray current.  Some state there is DC in AC.  If that were so every AC appliance, World-wide, would try to draw an infinite current and incinerate.

4:  Permanently wire one SeaBis to every independent DC source.  Every independent DC source generates stray current that causes stray current corrosion.  Protracted use as a portable will cause repeat stray current corrosion.  See next item.

5:  There are alternatives to using one SeaBis per independent DC source.  They however do increase the risk of corrosion going unobserved.  They are battery switches, an Inter-switch or SeaBis being moved from battery bank to battery bank as a portable with risk of stray current corrosion returning undetected.

6:  If you chose to use your SeaBis Master as a portable or flexible (non-permanent connection) ensure you monitor all battery banks at an interval less than 10 days divided by number of battery banks.  So, two battery banks every 5 days.  Three battery banks every 3 days.

7:  Some Charge Controllers / Reducer / Regulator, sometimes intermittently, will prevent your SeaBis Master from seeing stray current caused by their output load.  The solution is either not to use them or use an additional SeaBis connected to their outputs.

8:  Very large surface area outboard legs attract stray current.  There is a solution. 

Contact me: email

9:  Many causes are only visible when equipment is fully operational.  One cause, missed during initial tests is more than enough to cause stray current.  Indicate all causes by permanently wiring your SeaBis Master.  Do not accept a temporary test.  You will regret doing so. Alternators often cause stray current at full power, yet are Normal otherwise.

10:  LED lights are a common cause.  Insulate their bases – use non-conductive mounting plates and / or non-metal screws or bolts.

Important:  If you use both 12 and 24 volts then two SeaBis Masters are essential.  The use of both 12- and 24-volts triples stray current. (12 plus 24 volts plus differential of 24 minus 12 volts)

Important:  Your SeaBis Master will indicate stray current caused by the Battery Bank / Reducer / Regulator SeaBis Master is connected to at that time.

SeaBis Master warranty and guarantee are effective only when one SeaBis Master is permanently installed to every independent battery bank and our full How to Prevent Marine Corrosion instructions are completed and your SeaBis Master indicates Normal at all times (we do allow for caution indications stated previously in this document).  A SeaBis Master must permanently monitor every battery bank and DC source to warn you of stray current.  Use of a SeaBis Master without permanent connection will result in stray current occurring without your knowledge.

Remember our free training.  I much prefer you contact me and we will correct all stray current. Any difficulties contact me: email

Life expectancy, guarantee and fuses.

You can expect many years of trouble-free performance from your SeaBis Master.  Design life is 20 years.  Your new SeaBis Master is very heavily protected.  To blow a fuse requires 100 times the normal maximum current and that current has to be largely AC as full reverse polarity protection is inbuilt.

 If you blow fuses the cause is AC and that is usually reversed mains supply Active / Neutral / Earth or a cheap inverter.  All work on Mains / shore or inverter Power must be carried out by a fully certified, licensed AC Electrician.

Guarantee and warranty. 

Podean Electronic Industries Pty Ltd (trading as SeaBis) guarantees and warranties to replace or repair any unit with a manufacturing defect for eight years from date of purchase.  How to Marine Prevent Corrosion must be complied with.

  • Use other than permanently connected will reduce the eight years to 10 days – the time for stray current corrosion to be visible and stray current WILL occur without your knowledge.  Ignoring AC Only light will result in damage to batteries, electronics and increased risk of electrocution and void guarantee and warranty.  As supply is World-wide, Owner to pay shipping to our office.

Fuses, replacement:

Are 200 Mill-Amp fast blow type M205 and can be replaced by opening the fuse holders in the base.  If you have difficulty then I will replace fuses and thoroughly test SeaBis. Free.

If needed, we will assist with advice based on 2,000+ vessels and 100% success.  While How to Prevent Marine Corrosion and the Traffic Light System makes it unnecessary, we can advise a Technician / Electrician at your request.  In the unlikely event you have to use a technician it costs much less than stray current corrosion and we will train him – free.

Glen Bishop,

Any difficulties then contact me: email Glen Bishop

Full contact details at: Password is 8.

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