Where is the best thing to connect?

[jayhanig]

I had a hour meter added to my boat to keep up with time on the engine for scheduled maintenance purposes. Unfortunately, I've noted that the gauge is apparently tied in with what I will call the general 12 volt bus. In other words, if the main battery switch in the engine compartment is on, then the hour meter is active... which will eventually run my battery down as well as artificially show many more hours on the engine than actually exist. If that battery switch is on in the back, then everything electrical works in the boat, lights, electronics, gauges read, etc.

The existing gauges in my instrument panel include oil pressure, trim, water temp, voltage, fuel, speedometer, tach and of course the hour meter. Where is the best place to power that hour meter gauge from that will only be hot when the engine is actually turned on?

 

[matt167]

Re: Where is the best thing to connect?

Alternator output. Same connection as an electric choke.

 

[Bondo]

Re: Where is the best thing to connect?

I had a hour meter added to my boat to keep up with time on the engine for scheduled maintenance purposes. Unfortunately, I've noted that the gauge is apparently tied in with what I will call the general 12 volt bus. In other words, if the main battery switch in the engine compartment is on, then the hour meter is active... which will eventually run my battery down as well as artificially show many more hours on the engine than actually exist. If that battery switch is on in the back, then everything electrical works in the boat, lights, electronics, gauges read, etc.

The existing gauges in my instrument panel include oil pressure, trim, water temp, voltage, fuel, speedometer, tach and of course the hour meter. Where is the best place to power that hour meter gauge from that will only be hot when the engine is actually turned on?

Ayuh,.... SoP is to tap into the Key's ignition power for an hour meter....

When the key is On, so is the meter....

 

[Georgesalmon]

Re: Where is the best thing to connect?

Yes, I agree. The key is not perfect but very close. When my key is on the engine is running almost all the time anyway. And its an easy hookup. The 12vdc that powers your other gauges is typically the purple wire from the ignition switch and that's where me and lots of other people power their hourmeter. You can get fancy and power it from the oil pressure switch or alternator or something else that only has power when the engine is actually running but its a lot of piddeling around because those connections are not typically already in the engine harness, IMHO.

Edit: Just reread your post and you say the gauges all work when the batt switch is on? That's not typical. Usually the gauges don't get power until the key is on. On most boat engines the purple wire is 12vdc when the engine key switch is on and that is where the gauges are powered. including the hourmeter.

 

[Auger01]

Re: Where is the best thing to connect?

Connect the hour meter to an oil pressure switch and it will only measure the time the engine is actually turning.

 

[Don S]

Re: Where is the best thing to connect?

Connect the hour meter to an oil pressure switch and it will only measure the time the engine is actually turning.

Why would you need that kind of accuracy? The meters are only good for knowing when maintenance is due.

 

[jayhanig]

Re: Where is the best thing to connect?

Edit: Just reread your post and you say the gauges all work when the batt switch is on? That's not typical. Usually the gauges don't get power until the key is on. On most boat engines the purple wire is 12vdc when the engine key switch is on and that is where the gauges are powered. including the hourmeter.

You are correct. I described it poorly. When the battery master is on, then the instrument lighting can be operated. The gauges themselves don't come alive until the key is turned... except for my hour meter... which is what I'm going to fix. The present setup is problematic.

 

[jayhanig]

Re: Where is the best thing to connect?

Why would you need that kind of accuracy? The meters are only good for knowing when maintenance is due.

I don't, really. But what I don't need is the meter reading just because the batter master switch is on. What started me looking is an extra 20-30 hours on the meter with no corresponding time on the engine and a dead battery for no obvious reason other than I'd moved the hour meter to the other side of the cockpit to make room for my trim gauge in my panel. Obviously, something that was originally right no longer was.

 

[Don S]

Re: Where is the best thing to connect?

I don't, really. But what I don't need is the meter reading just because the batter master switch is on.

You don't hook it to the battery switch side of the ignition switch, you hook it to the ignition side, the I terminal, it will have a purple wire on it.
Or just hook it to the purple wire on one of the instruments, they get power from the same place, and a lot easier to get to.

 

[Silvertip]

Re: Where is the best thing to connect?

If the hour meter is in the vicinity of the gauges, hook the power lead to the "I" terminal on any of the gauges. That is the terminal that powers each gauge and hence the hour meter. Doesn't matter which one you pick.