System Monitor replacement for mechanical engines

ZZ13

ZZ13

Well-Known Member
Nov 25, 2009
5,322
Lady's Island, SC
Boat Info
2001 400 Sedan Bridge
Engines
Cummins 450 Diamond
When I bought the boat 8 years ago I dished out $800 for a new systems monitor DDU. Well a lightning EMP fried it a few weeks ago. I had no interest in another $800 purchase so I looked at alternatives. Since I have all mechanical engines with no Smartcraft and no Nmea2000, I went with the straightforward approach. I bought two $50 panels from Aqualarm. One for four bilge pumps and one for the four engine alarms I want (low oil and high temp on each engine). Here are the panels. They will be mounted side by side where the DDU was. Waiting on the engine panel to arrive.
5E28E052-EFD9-426B-B170-EEA619B4C384.jpeg
1DA9EF13-ABBB-42CA-A59E-101251505DAB.jpeg

Here is the Systems Monitor schematic for my boat that I used for the wiring:
97648E17-4233-4A97-AF14-FB498AA0F906.jpeg

Wiring the four bilge connections was straight forward. They go to +12v when active and the alarm panel triggers on sensing +12V. So I just cut the four wires off the connector and heat shrink butt connected them to a 16/4 cable that I chased to the bridge.

The engine alarm requires a relay for each wire to convert a ground signal (the engine sensors go to ground when active) to a +12v signal for the alarm panel. Here is the schematic I am using for that. I am awaiting the panel and the relays to arrive so that’s a future installation.
736BDB46-54BD-42E6-BCA5-337608E55B92.jpeg

i am not connecting the generator or transmission signals. My generator is a replacement and the installer did not add the dedicated system monitor oil switch, so nothing to wire up. And my boat does not have transmission temp switches installed so nothing to wire up there. And I am not wiring the shower sump pump. No value in that in my opinion. I’ll post a final picture when I get the second panel installed.
 
I'm doing something similar - Guess I'm just too old school.

Gotta re-do the faded dash panels with cutouts for old electronics anyway.

In addition to your plan I'll be adding:

  • trans oil temp gauges
  • generator oil pressure
  • generator water temperature
and also engine pyrometer & boost gauges.

emergency bilge pumps will be tied to an alarm and an indicator light

regular bilge pumps will be tied to a digital bilge pump counter

Maybe I missed something but that s failry accurate

RWS
 
I like the idea of having both analog gauges and idiot lights/audible alarms. Those panels you wired in look like the hot ticket.
 
@ZZ13 your idea of using relays is sound, I went that route as well to trigger my RIM100 (Digital System monitor) and also my EMU-1 alarms (Digital Engine converter).

Although relays work, they can be another failure point and if you reference the correct pos or neg the relays are not really needed. Not sure how the boards are wired. But if your going the replay route take a look at this: https://www.amazon.com/gp/product/B00LW2GA5Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I use these for my systems. I have them mounted in project boxes and made harnesses for the connections. They come in 2/4/8 relay packages. The best part about them are the are jumper configurable for a high or low trigger so they are perfect for this application.

Also make sure when you tie 327 & 32 together they are the same ground. Every ground on your boat should be all tied together at the source (batteries) and if they are not you can get different potentials for ground. Just a best practices point. I can not tell you how many times I have seen this be the source of electrical issues.

Good luck with the rest of your project, there is value in not having things all digital. But when done right digital has so much more potential and is expandable in many ways.
 
SKybolt said:
@ZZ13 your idea of using relays is sound, I went that route as well to trigger my RIM100 (Digital System monitor) and also my EMU-1 alarms (Digital Engine converter).

Although relays work, they can be another failure point and if you reference the correct pos or neg the relays are not really needed. Not sure how the boards are wired. But if your going the replay route take a look at this: https://www.amazon.com/gp/product/B00LW2GA5Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I use these for my systems. I have them mounted in project boxes and made harnesses for the connections. They come in 2/4/8 relay packages. The best part about them are the are jumper configurable for a high or low trigger so they are perfect for this application.

Also make sure when you tie 327 & 32 together they are the same ground. Every ground on your boat should be all tied together at the source (batteries) and if they are not you can get different potentials for ground. Just a best practices point. I can not tell you how many times I have seen this be the source of electrical issues.

Good luck with the rest of your project, there is value in not having things all digital. But when done right digital has so much more potential and is expandable in many ways.
Click to expand...
Let me see if I understand this. I can use the sender ground signal as the trigger, rather than +12v, by changing a jumper? And the output from that trigger will be the 12v needed to go to the alarm panel?
 
ZZ13 said:
Let me see if I understand this. I can use the sender ground signal as the trigger, rather than +12v, by changing a jumper? And the output from that trigger will be the 12v needed to go to the alarm panel?
Click to expand...

Yes, or what ever you wire in to the relay. The relay will still be a relay with a common that needs to be fed with +v or -v and then the NO side will go to the alarm panel PCB. The difference is that relay PCB has circuitry that allows for input level selection via jumpers. Works great and I have had it in operation for ~5 years so far. I also bought extra boards as backup's in case they don't sell them any longer. So I have an additional set all wired up ready to go if one dies. I use to check the SM regularly for proper operation, but it has never had an issue so far. Just jinxed myself, but it has been great.
 
Nater Potater said:
$10.59 for an 8 channel relay bank? Twenty years ago, that would have easily cost ten times that.

Bill, by merely moving the little black jumpers, you invert the input/output signals.
Click to expand...

Yep, exactly. A really awesome board and very well built. They have been selling them for a few years now as well. Great find and perfect for this application.
 
SKybolt said:
Yes, or what ever you wire in to the relay. The relay will still be a relay with a common that needs to be fed with +v or -v and then the NO side will go to the alarm panel PCB. The difference is that relay PCB has circuitry that allows for input level selection via jumpers. Works great and I have had it in operation for ~5 years so far. I also bought extra boards as backup's in case they don't sell them any longer. So I have an additional set all wired up ready to go if one dies. I use to check the SM regularly for proper operation, but it has never had an issue so far. Just jinxed myself, but it has been great.
Click to expand...
Got it. So the signal wire from the switch on the engine (which goes to ground when active) wires into the IN terminal?

Also what size wire will the connectors accept? I want to be able to stick two 16s in there so I can daisy chain the +12v to all four relay’s COM inputs.
 
Last edited:
ZZ13 said:
Got it. So the signal wire from the switch on the engine (which goes to ground when active) wires into the IN terminal?

Also what size wire will the connectors accept? I want to be able to stick two 16s in there so I can daisy chain the +12v to all four relay’s COM inputs.
Click to expand...

Yes the sender on the engine wires directly into the IN on the board.

To stay ABYC compliant you need to use at least 16ga wire, I wired mine with 14ga. All of the engine senders from the SM terminals I used yellow 14ga wire wrapped in a net style harness and used blue 14ga from the board to the RIM/EMU(s), in your case it would be the alarm panel(s). I also mounted the relay board in a "project" box with cable glands and deutsch connector's for easy removal. Amazon carries deutsch pigtails for easy assembly.

To daisy chain the common's you can use smaller gauge jumper wire. There is no current involved here and if the board is in a project box with the 16ga wire used for in/out then you are still ABYC compliant.
 
Thanks. At that price I will give them a tr
SKybolt said:
Yes the sender on the engine wires directly into the IN on the board.

To stay ABYC compliant you need to use at least 16ga wire, I wired mine with 14ga. All of the engine senders from the SM terminals I used yellow 14ga wire wrapped in a net style harness and used blue 14ga from the board to the RIM/EMU(s), in your case it would be the alarm panel(s). I also mounted the relay board in a "project" box with cable glands and deutsch connector's for easy removal. Amazon carries deutsch pigtails for easy assembly.

To daisy chain the common's you can use smaller gauge jumper wire. There is no current involved here and if the board is in a project box with the 16ga wire used for in/out then you are still ABYC compliant.
Click to expand...
Thanks. At that price I will give them a try. Ordering four two channel boards. One two channel for each engine and a spare for each engine.
 
The relays arrived. I tested it the way I want to use it and it works. With the jumper set to lo, COM is bridged to NO when IN goes to ground. Just what I want. It’s more of a hobbiest relay so the connectors are pretty small. Going to wire it all up to a terminal strip with 18-22 wires then connect the 16 gauge to the terminal strip.
 
ZZ13 said:
The relays arrived. I tested it the way I want to use it and it works. With the jumper set to lo, COM is bridged to NO when IN goes to ground. Just what I want. It’s more of a hobbiest relay so the connectors are pretty small. Going to wire it all up to a terminal strip with 18-22 wires then connect the 16 gauge to the terminal strip.
Click to expand...

Yeah, there made for the Arduino and PI applications, but I had no issues getting a single 14ga wire in the terminal. I did use solid jumper wire for the commons off of the power wire.
 
Njlarry said:
For old school has anyone used or looked into alarms be Borel engeneering?
Click to expand...

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Had BOREL EXHAUST ALARMS on my 10 meter for engines AND genny.

Purchased same for the 450 DA -

They're on the installation list along with

bilge alarms and

bilge counters

RWS
 
is the relay necessary?

In theory, why can't one simply run the wire direct ?

I did this as a test with the high water bilge - wired to a simple buzzer/alarm and it seems to work fine

Curious.....

RWS
 
Maybe A Dancer said:
is the relay necessary?

In theory, why can't one simply run the wire direct ?

I did this as a test with the high water bilge - wired to a simple buzzer/alarm and it seems to work fine

Curious.....

RWS
Click to expand...

He is using the relay board for the engine alarms which are a 12v negative (Ground) signal when active and float when not active. The relays are needed to give a 12v signal to the alarm panel.
 
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