Persistent Stray Current Leakage (~1V at Engine) – Need Advice!

[ravid007]

Hi everyone,

We're dealing with a frustrating electrical issue on our 2012 Bavaria Cruiser 36 and could really use some insights or outside-the-box suggestions from the community.

We've had a persistent stray current leakage for a while now, and it's severely accelerating anode/metal corrosion around the underwater gear. No matter what we test or disconnect, we cannot get the voltage reading at the engine down below 1.0V.

Here are a few key details and steps we've already taken to isolate the issue:

• Control Comparison: By chance, we have an identical Bavaria Cruiser 36 (same year, same specs, same options/equipment) berthed right next to us. When testing her in the exact same spot, her reading shows a normal 0.3V.
• Location Check: We tested our boat in a completely different marina to rule out shore/pier-induced stray currents or neighboring vessel issues. The reading on our boat remained unchanged at 1.0V.
  
• Isolation Testing: We've tried turning off individual DC breakers, isolating batteries, and disconnecting shore power, but we haven't been able to identify a single source bringing the potential down.
  

Given that the engine/Saildrive is reading 1V while our neighbor's identical setup sits at 0.3V, we're running out of ideas on where this current is bridging to the water.

Has anyone with a similar Bavaria setup experienced this? Are there any hidden ground bonding loops, battery charger/inverter leaks, bilge pump floating grounds, or Saildrive isolation issues specific to this model that we should inspect?

Any advice, suggestions, or troubleshooting steps would be hugely appreciated!

Thanks in advance!

[Yngmar]

Often its a forgotten/damaged saildrive cone washer: https://fybmarine.shop/volvo-penta-saildrive-cone-plastic-washer-part-number-850888

[SYJetzt]

Is your saildrive including the gearbox isolated from the engine...?