Excite me please ?

[wingcommander]

Just replaced an antiquated charge system with a less antiquated and simpler VSR . Simple setup ,starter batt and house bank. The original setup was alternator exciter wire connected to house bank common on isolator.
I am curious as to why it was not connected to the start battery common. I realise its still getting the required voltage Does it make any difference .

Thanks
Paul

 

[Sandy]

I just have one common on the boat, why do you have two?

 

[wingcommander]

Sorry , may my wrong terminology . I meen the battery side of the isolation switch + ve .
I am relating to common side of th switch , the other connection being switch open or switch closed.
Nothing at all to do with neutral/ earth / common.

Hope this makes sense. As is common sense Lol

 

[wingcommander]

Like this

Google Image Result for https://www.downlights.co.uk/media/FAQs/wiring-example-1-way-switch.jpg

 

[Alex_Blackwood]

Just replaced an antiquated charge system with a less antiquated and simpler VSR . Simple setup ,starter batt and house bank. The original setup was alternator exciter wire connected to house bank common on isolator.
I am curious as to why it was not connected to the start battery common. I realise its still getting the required voltage Does it make any difference .

Thanks
Paul

Are you sure it is not the sensing wire as opposed to excitation?

 

[wingcommander]

Are you sure it is not the sensing wire as opposed to excitation?

Awe,
Does that mean I need to change my thread title.
Its the wire that exits the alternator (circa 2.5mm csa) and runs directly to aforementioned switch. Not the charge lamp wire.

 

[wingcommander]

Google is my friend. Thanks Alex it is the sensing wire. Just curious as to why originally it was sensing off the house and not the starter

 

[Alex_Blackwood]

Google is my friend. Thanks Alex it is the sensing wire. Just curious as to why originally it was sensing off the house and not the starter

Once the engine battery was charged the alt. Would sense that and "Stop" charging so house would not get fully charged.
Should be OK as is but may be better connected to input of VSR. Not 100% on that. Perhaps Paul R. May qualify!

 

[VicS]

Google is my friend. Thanks Alex it is the sensing wire. Just curious as to why originally it was sensing off the house and not the starter

As Alex says it was previously connected to the house battery bank because that would probably have been the battery which was the more deeply discharged.
If the starter battery was sensed , and it recharged quickly the house bank would not be fully recharged or at least would be charged only slowly.

Now you must connect the sensing to the battery which is the 1st charged by the alternator/VSR combination... usually that is the starter battery . That is more or less the the same as Alex's suggestion to connect it to the VSR Input.

It would be useful if you posted a wiring diagram to show how you have connected ( or intend to connect ) the alternator output., VSR, isolating switches, batteries and sensing.

( You do not say if you still have the Bukh engine or if you have replaced it with a Beta. )

 

[wingcommander]

As Alex says it was previously connected to the house battery bank because that would probably have been the battery which was the more deeply discharged.
If the starter battery was sensed , and it recharged quickly the house bank would not be fully recharged or at least would be charged only slowly.

Now you must connect the sensing to the battery which is the 1st charged by the alternator/VSR combination... usually that is the starter battery . That is more or less the the same as Alex's suggestion to connect it to the VSR Input.

It would be useful if you posted a wiring diagram to show how you have connected ( or intend to connect ) the alternator output., VSR, isolating switches, batteries and sensing.

( You do not say if you still have the Bukh engine or if you have replaced it with a Beta. )

All connected via a typical two separate isolation switch setup , as yet no facility to combine , may add this switch later , will reposition the sense wire next visit. I can now understand why it was previously connected to the house battery. Bukh is performing admirably , treating her to a new set of shoes (RAB 2 designer models)

 

[Alex_Blackwood]

As Alex says it was previously connected to the house battery bank because that would probably have been the battery which was the more deeply discharged.
If the starter battery was sensed , and it recharged quickly the house bank would not be fully recharged or at least would be charged only slowly.

Now you must connect the sensing to the battery which is the 1st charged by the alternator/VSR combination... usually that is the starter battery . That is more or less the the same as Alex's suggestion to connect it to the VSR Input.

It would be useful if you posted a wiring diagram to show how you have connected ( or intend to connect ) the alternator output., VSR, isolating switches, batteries and sensing.

( You do not say if you still have the Bukh engine or if you have replaced it with a Beta. )

Yes, Just done a bit of revision on VSR's Sensing goes to engine battery, (VSR Input). I am not familiar with VSR's from a hands on perspective so like to err on the side of caution!