Installing buzzer on ignition circuit?

[neil1967]

On my Oyster 4108 instrument panel there is a 12v warning light to indicate when the 'ignition' is switched on. The light goes out when I heat the engine and remains out once the engine (Perkins 4108) is running. I understand that as well as being a warning that the ignition is on (and the engine not running), the light also serves as a load to stimulate the alternator into action. When stopping the engine the light comes back on to remind you to turn the ignition off. The light is not terribly bright and it is easy to miss. On other yachts I have sailed on there has been a buzzer either in place of, or in addition to, the light, which makes it very clear that the engine isn't running but the ignition is on. So, can I just wire a 12v buzzer in parallel to the ignition warning light, or indeed just replace the light in toto? The buzzers I have seen (ASAP supplies) do not have a tech spec in terms of resistance or load, so is it just a case of trying it out?ThanksNeil

 

[earlybird]

I think that you can put a buzzer across the lamp supply.
If it's any help, the buzzer on my Beta panel is a Kingstate KPEG251. Farnell sell them, but I bought one off Ebay when my original failed, ~£4.
Since the max. current is specified as 5mA, the buzzer alone might not excite the alternator, so keep the lamp, or a resistor.
Edit; Just looked at ASAP, they offer the MB12, which seems fairly widely available on-line, the spec. that I found suggests 15mA @12v, so might be a better bet.

 

[emmalina]

Strange as you only have the one light I have 2 One to excite the alternator and a buzzer/light for the engine oil pressure sensor that doubles as a ignition light.

 

[VicS]

On my Oyster 4108 instrument panel there is a 12v warning light to indicate when the 'ignition' is switched on. The light goes out when I heat the engine and remains out once the engine (Perkins 4108) is running. I understand that as well as being a warning that the ignition is on (and the engine not running), the light also serves as a load to stimulate the alternator into action. When stopping the engine the light comes back on to remind you to turn the ignition off. The light is not terribly bright and it is easy to miss. On other yachts I have sailed on there has been a buzzer either in place of, or in addition to, the light, which makes it very clear that the engine isn't running but the ignition is on. So, can I just wire a 12v buzzer in parallel to the ignition warning light, or indeed just replace the light in toto? The buzzers I have seen (ASAP supplies) do not have a tech spec in terms of resistance or load, so is it just a case of trying it out?ThanksNeil

If you have a low oil pressure warning light it will avoid any complications if you wire the buzzer in parallel with that.

If will also then serve asaan audible warning of loss of oil pressure.

 

[neil1967]

The engine has an oil pressure sensor and gauge and does not have an oil pressure warning light. Not sure if there is also an oil pressure switch fitted - I doubt it, but I will check.

 

[PaulRainbow]

The engine has an oil pressure sensor and gauge and does not have an oil pressure warning light. Not sure if there is also an oil pressure switch fitted - I doubt it, but I will check.

Just wire a buzzer in parallel to the ign light, that's how it's usually done on simple setups like the Perkins.

 

[PaulRainbow]

Strange as you only have the one light I have 2 One to excite the alternator and a buzzer/light for the engine oil pressure sensor that doubles as a ignition light.

You have an alternator lamp (commonly referred to as an ignition lamp) and a low oil pressure warning lamp. The alternator lamp comes on if the alternator is not charging and the oil light comes on if the oil pressure is lost. Both will come on if the engine is not running, for obvious reasons, and the buzzer can be wired to either. In fact, you could have buzzers wired to both.

 

[VicS]

You have an alternator lamp (commonly referred to as an ignition lamp) and a low oil pressure warning lamp. The alternator lamp comes on if the alternator is not charging and the oil light comes on if the oil pressure is lost. Both will come on if the engine is not running, for obvious reasons, and the buzzer can be wired to either. In fact, you could have buzzers wired to both.

Or as is commonly done one buzzer and diodes to connect it to two or more warning lights.

 

[PaulRainbow]

Or as is commonly done one buzzer and diodes to connect it to two or more warning lights.

Yes, either is perfectly acceptable, separate buzzers might be an easier DIY install for someone who has little electrical knowledge.

 

[VicS]

Yes, either is perfectly acceptable, separate buzzers might be an easier DIY install for someone who has little electrical knowledge.

The OP says Electronics is one of his interests so hopefully wiring in a "buzzer" with a couple of diodes will not present any great difficulties.

Puzzled though why I have failed to find a wiring diagram for his engine!

 

[PaulRainbow]

The OP says Electronics is one of his interests so hopefully wiring in a "buzzer" with a couple of diodes will not present any great difficulties.

Puzzled though why I have failed to find a wiring diagram for his engine!

With 12v buzzers at 99p, delivered, i wouldn't mess around fitting diodes.

There will be about a million different boats fitted with the 4108. It's a very basic engine and is not likely to have been fitted with any of the stupid electronic panels Volvo dreamt up.

Default oil warning for the engine in its automotive habitat would just be an oil light. Typical marine installation is likely to be an electric gauge. No reason not to fit a combined sensor to do both, or to tee off the gallery and fit separate sensors, should anyone desire an oil light and/or buzzer.

To answer the OPs original question, again, just fit a 99p Ebay buzzer in parallel with the lamp. Doesn't need to be any more difficult than that.

 

[neil1967]

Thanks all - I think I'm up to wiring in a buzzer

 

[PaulRainbow]

Thanks all - I think I'm up to wiring in a buzzer

Didn't doubt it Neil, my point was, for 99p why make it more complicated and most likely more expensive by using diodes, rather than a second buzzer :encouragement: