System Monitor replacement for mechanical engines

[Gallf1]

Panels installed, tested and functioning. I have a spare slot in the Engine System panel for future alarm.
There is a slight seam between the two panels where they touch so I may add a very carefully applied bead of Black Silicone.

 

[Pierpressure1]

I would like to thank everyone that contributed to this replacement option for the system monitor. My original unit was inoperable the last couple years and I felt like I was living dangerously not having it so I made it a priority to complete this mod over the winter.

Last week we took. the boat out for a shake down cruise after the 1000 hour service was completed by a local shop. The hard pipe coming off the top of the fresh water pump became dislodged and the engine had a catastrophic loss of coolant. My new alarm worked to alert me and I was able to shut the engine off before any damage was done. The new alarm is so loud there is no way to miss it.

 

[ZZ13]

I’m 20 months into this solution. A couple days ago I had one of the four 10 amp relays go bad when I started the engine in 38 degree weather. NO output is now stuck permanently closed. I had several spares so I swapped a new one in and all is good. Will continue the longevity testing. If failures continue then I’ll replace with 30amp Bosch relays. Hopefully just a fluke failure.

 

[ZZ13]

Finally got around to replacing my “prototype” with something a bit better looking. Cut a plastic cutting board down to size and added 10amp breakers to each power input, since the relays are only rated for 10amps.

 

[Skybolt]

... If failures continue then I’ll replace with 30amp Bosch relays. Hopefully just a fluke failure.

The problem there is no level shifting and the senders can't drive a relay. That's why those relay boards are so perfect. Also they belong in a project box to protect against being hit with water.

But if the NO side was fused, what were you driving with it? I only use them to drive digital inputs like the Actisense EMU-1 or a Maretron RIM100.

 

[ZZ13]

The problem there is no level shifting and the senders can't drive a relay. That's why those relay boards are so perfect. Also they belong in a project box to protect against being hit with water.

But if the NO side was fused, what were you driving with it? I only use them to drive digital inputs like the Actisense EMU-1 or a Maretron RIM100.

+12v on COM. Trigger is GND. Works well. The blown relay turned out to be from a starter fault that caused more than 10 amps to get pulled through the relay.

You are right. I should box it in. Right now it’s in a closed compartment inside the boat. So not much chance if it getting wet. Maybe some humidity now and then. I’ll box it up soon….