Wiring engine hours counter to alternator

[Ric]

I have the usual Volvo engine hours LCD problem, so have ordered a Curtis 701 counter which I would like to connect to my Volvo MD2020.

The 701 series have three connection wires - one to power the instrument, one to trigger counting, and of course the earth.

I'd like to wire the first so that when I switch on the engine circuit breaker, the instrument is on, and the second to the alternator so that hours are counted only when the engine is running.

Can anybody tell me which terminal I need to connect to on the alternator? Are there three terminals on an alternator that correspond to the instrument connections required - that would make installation very easy as I could run a single three-core wire to the alternator.

 

[VicS]

If you really want to connect it to the alternator,

The power for the contiuous display from the main + alternator output via a fuse
Negative from the negative terminal if there is one other wise the alternator case.

Signal since it works on DC or AC from the tacho (W) connection. ??????


If your engine has an insulated negative return take care not to compromise that ...... Depends on the Version ( ABCorD ITYWF) Refer to the engine wiring diagram in the owners manual.

Personally would wire it into the engine control panel

+ input to the panel and ign switch for the power for contiuous display

any where convenient to connect to the negative

Try the tacho signal input from W other wise cnnect to positive which is live when the ign switch is on. The existing is wired like that ITYWF and runs all the time the ign is switched on

Cant think why you want a contiuous display of engine hours.

 

[rogerthebodger]

Vic

I seem to remember that the W terminal only has an AC signal when the alternator is generating i.e. when the ign light is out. So at tick over the W terminal may not produce a signal to drive the hour meter.

This will depend on the ratio of alternator drive belt and one of my alternators is geared such as to generate at tick over but my other does not.

I drive my hour counter from the oil pressure switch but my hour meter is a different type

 

[superheat6k]

Assuming you want your run hours fairly accurate, otherwise you could simply connect it to the accessory on feed from the ignition.

The following avoids messing around with the alternator. You will need a simple 12vdc relay from Maplins or similar.

!2v feed from oil light circuit to the coil of the relay, with neg to other sie of coil (normally A1 & A2).

12v feed from the accessory feed via a pair of NC contact connections through the relay.

When the oil light is on the NC will be open, so the hour counter will only clock when the oil light is off and the ignition accessory is on, i.e. when the engine is running.

 

[VicS]

Vic

I seem to remember that the W terminal only has an AC signal when the alternator is generating i.e. when the ign light is out. So at tick over the W terminal may not produce a signal to drive the hour meter.

This will depend on the ratio of alternator drive belt and one of my alternators is geared such as to generate at tick over but my other does not.

I drive my hour counter from the oil pressure switch but my hour meter is a different type

You may be right although the tacho shows the engine revs when idling!

I only suggested it because the OP wanted to make all connections from the alternator and W was the only place I could think of for that connection.

As i indicated I'd wire it in parallel with the original. Will run all the while the ign is on but thats usually only when the engine is running

 

[Daydream believer]

I have an hour meter from RS following advice an earlier thread 2 years ago
I have a Volvo md 20 20
The hour meter uses 2 wires ( provision for 4)
The blue wire goes to the same terminal on the alternator as the large black wire
The red one goes to the terminal marked "D+"
The hour meter only works of the engine is running & does work on tickover
I have checked it several times & , for example, on a 15 hour run it is virtually dead on

 

[nigelmercier]

... Will run all the while the ign is on but thats usually only when the engine is running

Quite, that's what I've done.

To the OP, have you still got the LCD glass from the old counter? I need one to play with.

 

[Ric]

Quite, that's what I've done.

To the OP, have you still got the LCD glass from the old counter? I need one to play with.

I want to keep the old LCD as it does occasionally spring into life.

 

[Ric]

You may be right although the tacho shows the engine revs when idling!

I only suggested it because the OP wanted to make all connections from the alternator and W was the only place I could think of for that connection.

As i indicated I'd wire it in parallel with the original. Will run all the while the ign is on but thats usually only when the engine is running

I am not dead-set on wiring it to the alternator - just looking for a simple installation. As you suggest, it might be better to wire it up to the ignition. My ideal setup would be that the LCD illuminates when the engine battery master is on (so I can easily check the engine hours from the chart-table without having to switch the ignition on in the cockpit, and the display would also serve as a reminder to turn off the battery master when leaving the boat). I also want the new display to count the same hours as the original display, as the original does occasionally spring into life in winter.

So does anybody know whether the original counts hours when the motor is actually running? Or merely hours when the ignition is switched on? I can't check this at the moment as the original is not working at the moment.

 

[VicS]

I am not dead-set on wiring it to the alternator - just looking for a simple installation. As you suggest, it might be better to wire it up to the ignition. My ideal setup would be that the LCD illuminates when the engine battery master is on (so I can easily check the engine hours from the chart-table without having to switch the ignition on in the cockpit, and the display would also serve as a reminder to turn off the battery master when leaving the boat). I also want the new display to count the same hours as the original display, as the original does occasionally spring into life in winter.

So does anybody know whether the original counts hours when the motor is actually running? Or merely hours when the ignition is switched on? I can't check this at the moment as the original is not working at the moment.

ITYWF it counts hours when the ignition is switched on, regardless of whether or not the engine is running.

If you want it to agree with the existing one you you will have to set it to the current reading before you install it.

It would be nice to replace the existing display with a new display . Nobody has as yet published any scheme to do that although the method replacing the display with a complete new counter is well known.

 

[Daydream believer]

Are you sure it counts hours when the ignition only is on?
I don't think my one did
It would seem pointless doing so
Surely one wants running time as a check on fuel use , oil change time etc
Plus if one arrived at a destination & forgot to turn the ignition off then it would record the wrong hours
i am assuming the ignition is not used to turn the engine off, only the power
Mine is stopped on the decompression lever so the ignition would stay on
Recording ignition hours would put the hours up & if one wanted to sell the boat a high hour readout would put one at a disadvantage

 

[VicS]

Are you sure it counts hours when the ignition only is on?
I don't think my one did
It would seem pointless doing so
Surely one wants running time as a check on fuel use , oil change time etc
Plus if one arrived at a destination & forgot to turn the ignition off then it would record the wrong hours
i am assuming the ignition is not used to turn the engine off, only the power
Mine is stopped on the decompression lever so the ignition would stay on
Recording ignition hours would put the hours up & if one wanted to sell the boat a high hour readout would put one at a disadvantage

Reasonably certain. If the ignition was left switched on after stopping the engine wouldn't the alarm buzzer be sounding?

 

[nigelmercier]

... If the ignition was left switched on after stopping the engine wouldn't the alarm buzzer be sounding?

Indeed it would. However, the original hours counter stopped when there was no signal. Not really necessary IMO.

 

[Daydream believer]

Reasonably certain. If the ignition was left switched on after stopping the engine wouldn't the alarm buzzer be sounding?

Mine only buzzes for a short bleep when engine stops
I am pleased it does because I often turn the ignition on ready in certain situations ie shipping lane-if the buzzer was sounding i could not do that

 

[Ric]

I hazily remember that mine only counted hours when the motor was actually running, but it would be at least seven years ago when I experimented so I can't be sure any more. I am not sure from looking at the wiring diagrams either. It would be nice to know for sure. As there are some electronics experts here I have attached the wiring diagrams from the manual here - perhaps somebody could work it out from that?

 

[VicS]

No the forum does not allow clickable images from outside sources.

Upload them as directly attachments then you'll get clickable thumbnails or better still save thenm to Photobucket and post them as fullsize images

In any case if these are the wiring diagrams from the owners manual they do not show if the counter runs all the while the ignition is on or if it only runs while the engine is running

If you remember that it only runs while the engine is running then that is probably correct and my assumption is wrong

Owners manuals on http://www.volvopenta.com/volvopent...lication_search/pages/publication_search.aspx

 

[Ric]

Thanks Vic for explaining how to upload stuff again - here they are as attachments:

View attachment 44280

View attachment 44279

Would you have any suggestions as to the best place to wire in the hours meter? The existing rpm/hours counter appears to have two inputs, S+ and S-, but I am not sure what these mean. S+ seems to be connected (via 16 pin terminal block) to the W terminal of the alternator, so would this be the tacho input? In which case, would S- be for the hours counter? Unfortunately I don't understand what S- is attached to.

 

[VicS]

Thanks Vic for explaining how to upload stuff again - here they are as attachments:



Would you have any suggestions as to the best place to wire in the hours meter? The existing rpm/hours counter appears to have two inputs, S+ and S-, but I am not sure what these mean. S+ seems to be connected (via 16 pin terminal block) to the W terminal of the alternator, so would this be the tacho input? In which case, would S- be for the hours counter? Unfortunately I don't understand what S- is attached to.

No I dont understand why only one of the two tacho inputs appears to wired to anything either.

Personally Id wire the hour counter to the + and - terminals of the tacho or some other convenient points on the switched R/BL and SB wiring and not worry about the fact that it will accumulate a few extra seconds over the actual running time. Surely you don't time your service intervals with that degree of precision.

 

[nigelmercier]

... It would be nice to know for sure...

I can confirm with full certainty that the VDO Oceanline tachometer with engine hours counter does not increment the hours unless there is an tachometer input signal. I know this because I specifically checked it on my workbench.

I suspect other VDO models are the same, for other brands I have no idea.

 

[Ric]

Nigel,

Thanks for that - it would appear therefore that the signal for the engine hours counter comes from the terminal marked S+ in the instrument wiring diagram, which is connected to terminal W of the alternator. Thus I can connect the replacement hours counter to the alternator, which would be an easier installation given the layout of my boat. An earlier poster reported that he had successfully connected directly to the alternator, so this would appear consistent. I'll try it out today.