Adding a hour meter - Hunter 30

[Skipper7E]

I want to add a hour meter on a 1989 Hunter 30. I thought that I could get power of the alternator once the key was turned on but the only power is the batter power and it is hot all the time.
Any thoughts on how to hook this up? Panel is a B type with a key switch and start button.

 

[Stu Jackson]

Use the key switch.

 

[Skipper7E]

Thanks Stu, I thought about that but it would be a real chore to pull it back to the navigation table. I was hoping for something on the engine but I may have to do that.

 

[Ralph Johnstone]

In the past, I have used an electronic relay off the low oil pressure alarm circuit to supply power to a 12V fan. Electronic relay, because it had a 2 mA draw. If the fan had been put across the circuit directly:

1. the oil alarm would always be activated because the fan would act as a ground.
2. the fan would not run because the alarm has too much resistance.

I know, "Big Deal" so much for my case. But here's my point: check out the amperage draw on your electronic hour meter when placed across your 12V battery using a multimeter. If it's only a few mA, you should be able to pull power from your oil pressure circuit without sounding the "low oil pressure" alarm.

I know you know this, but I'll mention it anyway: tap into the oil pressure circuit AHEAD of the pressure switch or you'll be on the ground side.

I can't find any info on the power required for an electronic hour meter. Let us know.

 

[Stu Jackson]

Thanks Stu, I thought about that but it would be a real chore to pull it back to the navigation table.

@Skipper7E Have you considered moving the meter? It's something you don't have to look at regularly anyway.

 

[Claude L.-Auger]

Locate the positive wire coming from the key where it gets in the engine room. It might be easier to splice into it there than running to the key switch. You can ground on the bus bar behind your electrical panel.

 

[DJAY]

I don't know about electronic meters as Ralph mentions but for an old fashioned Hobbs meter, I simply took power off the oil pressure switch and put mounted the meter in the engine compartment.

 

[Ralph Johnstone]

T

for an old fashioned Hobbs meter, I simply took power off the oil pressure switch and put mounted the meter in the engine compartment.

WOW !

If an old electro-mechanical hour meter load was that small, I would think the newer electronic hour meters will do the job with very little mA draw.

 

[jssailem]

Fortunately the power demand of a Hobbs meter is not a significant load when the engine is running, and when the engine is off it is nothing.. too cool...

 

[DJAY]

Probably got lucky but it works. I’m here learning from you guys... in awe of the knowledge you all share so graciously

 

[Ralph Johnstone]

Fortunately the power demand of a Hobbs meter is not a significant load when the engine is running

It's not how much current the meter draws, but a question of "will the amount affect the low oil pressure alarm" ?

Here's a piece of my drawing for the 12V exhaust fan for the engine compartment:

 

[Ralph Johnstone]

in awe of the knowledge you all share so graciously

Now, now, there's nothing gracious about it !

We trust the royalty cheque is in the mail .

 

[Skipper7E]

Thanks everyone for your feed back. I'm leaning towards the oil pressure idea. I mounted the meter in a hole that was in the motor housing. There was a fuel gauge that no longer worked and the hole was perfect.
I;ll let you know what I find...

 

[Benny17441]

Like others have said the hour meter is connected to the key switch. The logic behind this is that when you turn the key on is because you are going to start the engine and not to listen to that awful buzzer. It is also convenient to mount close to the control panel.

 

[senang]

I have a 2004 Yanmar 3JH4E with the simple Yanmar panel. There is a provision for an alarm light for “water in sail drive”. Since my boat came with shaft drive, I located the wiring for this in the engine compartment and used that wire for the hour meter.

 

[woofetc]

Here’s the setup on our hunter 33 - Hobbs meter connected to run switch

 

[Ron20324]

Aw, come on, Woof. All the rest looks so good, fix that insulation on that red wire/connecter.

 

[woofetc]

Aw, come on, Woof. All the rest looks so good, fix that insulation on that red wire/connecter.

Wasn’t me..

 

[jssailem]

Ron with the eagle eye for possible corrosion potentially shorting experience.

Acceptable Woof response. And you may never have noticed it. But now it is identified.

If it corrodes and shorts out the boat, or starts a small Fire , who is it on?

 

[woofetc]

Seriously, you gotta be kidding? You didn’t notice the multitude of exposed contacts by design. No I didn’t notice the tiny section of exposed 12v wire but I’m not going to lose any sleep over it..