Just completed a 2900nm tough passage - two little switches almost ruined my month: Bilge Float Switch and Volvo D3-110C auxiliary stop
Scott SV Tengah
We just completed a 2900nm passage from Hawaii to French Polynesia with pretty rough upwind/up current conditions for the first 10 days or so. Just a bit longer than the Atlantic crossing but much more difficult, with days on end at 38-40 degrees apparent, bashing into current and waves. The second half was a bit better, but two little failed switches almost ruined our trip.
1) The on-off switch for our bilge pump float tube failed. I presume it's the original - 13 years old. Internally, it corroded and while it has been working perfectly during our ownership until now, the resistance finally got high enough that it didn't activate the bilge pump when the water level rose in the gray water bilge. The quick connect tabs are not well sealed and I believe this is how moisture gets into the switch.
The secondary bilge water level alarm on my A54 is located to port of the gray water bilge. Because this was a hard upwind port tack, the gray water (and saltwater from the anchor well and bow deck locker) pooled to starboard and NEARLY SUBMERGED THE ALTERNATORS. I would guess another few hours or another shower or two and it would have been an expensive problem.
I would suggest everyone check their bilge switches for resistance in the "on" position. Ours was approaching 500 ohms. It's a bit of a custom job, so you may want to plan on having a backup made or purchase one from Amel.
I also intend to install a water sensor on the float tube itself, in case we ever find ourselves on another multi-day port tack upwind adventure with a dead switch or bilge pump.
2) We have been having intermittent electrical issues with our Volvo D3-110C where it would turn off randomly, generally with the helm display going blank. Further, the Volvo displayed voltage was always 0.1-0.3v less than what we measured at the engine-side battery cables and less than what was displayed on our Onan remote panel. I believe I have found the problem and I believe it's a design fault resulting from Volvo's adaptation of a car engine for marine use.
On the starboard side of the engine lid/cover is an "auxiliary stop button" that is normally closed and allows power to flow to the ECU. When you press this button, it opens the circuit and depowers the ECU, turning off the motor.
The problem is that this switch is not sealed and is in the path of the engine room intake fan. That means salty air is blown onto it and since it's not sealed, it will corrode internally over time. See attached photo. We had a motor that would die randomly and had major difficulty starting up as we were heading south from the doldrums into southerly winds. Not a great place to have an intermittent motor.
After finding the problem, I simply butt connected the two wires leading into the aux stop switch and if we can't find a SEALED replacement switch, we will likely leave it as such. The aux stop switch is redundant there because you can always remove the ECU blade fuse right next to this faulty switch.
I'd suggest owners of the D3-110 check resistance on their aux stop switch. Also examine the quick connect spade connectors - both of mine were corroded from the constant flow of salty air.
Hope this helps someone.
2007 A54 #69