BEP VSR wiring

[davidej]

My boat (Beneteau 361) has a large house battery and a separate smaller motor start battery, each with a different isolator and a single negative isolator.

The mains and small solar panel only charge the house battery.

The VSR is wired as recommended for a single sensing, ie with the red going to the motor side of its isolator. But it is actually a dual sensing and the recommendation for this is for the red to go to the battery side of the motor isolator.

Will this make any difference to the ability of the alternator to charge the house battery when the motor is running ? After all, in this situation the isolator is closed so both sides are at the same voltage.

The only difference, as I see it, is that when the mains charger raises the house battery voltage sufficiently to trigger the VSR, the motor battery would not get charge unless its isolator was closed.

Anybody got any thoughts on this?

 

[BabaYaga]

The more direct the path between alternator and house bank is, the better, in my view. So leave the connection where it is.
(In fact I would connect the alternator directly to the house bank and feed the starter battery through the VSR, but most people seem to disagree on this).

 

[VicS]

My boat (Beneteau 361) has a large house battery and a separate smaller motor start battery, each with a different isolator and a single negative isolator.

The mains and small solar panel only charge the house battery.

The VSR is wired as recommended for a single sensing, ie with the red going to the motor side of its isolator. But it is actually a dual sensing and the recommendation for this is for the red to go to the battery side of the motor isolator.

Will this make any difference to the ability of the alternator to charge the house battery when the motor is running ? After all, in this situation the isolator is closed so both sides are at the same voltage.

The only difference, as I see it, is that when the mains charger raises the house battery voltage sufficiently to trigger the VSR, the motor battery would not get charge unless its isolator was closed.

Anybody got any thoughts on this?

Connect your VSR to the battery sides of the isolators. and its negative connection to the battery side of the negative isolator

Connect your mains charger and your solar charger to the battery side of the house battery isolator via suitable fuses .

The battery charger and the solar will then be able to charge the batteries even when all the isolators are open, giving priority to the house battery.

When the engine is running you will obviously have the engine battery isolator, and the negative isolator, closed. The alternator will then charge the starter battery as its first priority.


You might also like to include a switch in the VSR negative connection so that if you want to disable the VSR for any reason you can do so by opening that switch

 

[Heckler]

It would have been helpful if you had said exactly waht VSR you have. It would then be possible to refer to the installation instructions.

However:
Connect your VSR to the battery sides of the isolators. and its negative connection to the battery side of the negative isolator

Connect your mains charger and your solar charger to the battery side of the house battery isolator via suitable fuses .

The battery charger and the solar will then be able to charge the batteries even when all the isolators are open, giving priority to the house battery.

When the engine is running you will obviously have the engine battery isolator, and the negative isolator, closed. The alternator will then charge the starter battery as its first priority.


You might also like to include a switch in the VSR negative connection so that if you want to disable the VSR for any reason you can do so by opening that switch

Unless someone has fitted a vsr there isnt one fitted to Benes of that era. There is a strap fitted between the load side of the main positive switches so that when both are on then both batteries charge from the engine. The mains battery charger has connections to both battery sides of the switches so both should charge when on mains even though the isolators are off.
Stu

 

[VicS]

Unless someone has fitted a vsr there isnt one fitted to Benes of that era. There is a strap fitted between the load side of the main positive switches so that when both are on then both batteries charge from the engine. The mains battery charger has connections to both battery sides of the switches so both should charge when on mains even though the isolators are off.
Stu

He refers to a BEP VSR ! So presumably it must have been fitted by someone.

Not sure what the best way of connecting a dual output cahrger will be though.

Leave as at present connected to both batteries or, combine both outputs ( if permissible) and connect to the house battery only , allowing the vsr to connect the starter battery when the house battery is charged.

 

[davidej]

Unless someone has fitted a vsr there isnt one fitted to Benes of that era. There is a strap fitted between the load side of the main positive switches so that when both are on then both batteries charge from the engine. The mains battery charger has connections to both battery sides of the switches so both should charge when on mains even though the isolators are off.
Stu

Yup - I fitted it..
I have put another isolator in the strap which i can close when i need to as per the instructions that came with the V S R

 

[VicS]

Yup - I fitted it..
I have put another isolator in the strap which i can close when i need to as per the instructions that came with the V S R

I have now had a quick look at the instructions for the BEP VSR.

You don't need to use the ignition switch controlled feature. You want it to operate with the solar and mains battery charger presumably rather than only when the ignition is on. Therefore reconnect the red wire as originally supplied

 

[BabaYaga]

The battery charger and the solar will then be able to charge the batteries even when all the isolators are open, giving priority to the house battery.

This may be exactly what the OP desires, but from a general point of view I find it difficult to see the benefits of always feeding the starter battery, which is normally already fully charged. Maybe if the engine is very difficult to start or if the starter battery has other loads, besides the starter.
Recharging a large house bank by mains charger means it will sit for many hours at absorption voltage (14,4 V or so). In the long run this does no good for a small starter battery that is already fully charged.

 

[davidej]

Unless someone has fitted a vsr there isnt one fitted to Benes of that era. There is a strap fitted between the load side of the main positive switches so that when both are on then both batteries charge from the engine. The mains battery charger has connections to both battery sides of the switches so both should charge when on mains even though the isolators are off.
Stu

Yup - I fitted it.

I put an isolator in the strap which i can close when i need to- as per the instructions that came with the VSR

 

[Heckler]

Yup - I fitted it.

I put an isolator in the strap which i can close when i need to- as per the instructions that came with the VSR

Ah, ok. Having had two Benes with the same system, ie just the strap, I have never seen the need to change the system. I only switch the engine battery off if I am anchored, just as a fail safe. My house system was 440 amphrs, now 330 amp hrs after my battery cooking episode! The old ones were 9 years old!
Stu

 

[VicS]

Ah, ok. Having had two Benes with the same system, ie just the strap, I have never seen the need to change the system. I only switch the engine battery off if I am anchored, just as a fail safe. My house system was 440 amphrs, now 330 amp hrs after my battery cooking episode! The old ones were 9 years old!
Stu

People like to "upgrade" their systems .......... I did not say "improve" though!

 

[davidej]

The reason for starting this thread is that I don't think my alternator is charging the house battery properly, and I just can't diagnose the problem.

When I start the motor, the motor battery voltage immediately rises to about 14.0-14.1. The house battery voltage only rises to about 12.7 and then creeps up very slowly. If I close the isolator which I referred to in post #6 and which parallels up the two batteries, the house battery voltage also immediately rises to about 14.

I have checked the VSR (as far as I am able) by disconnecting the house battery connection and the voltage on it rises from zero to 14 when I start this motor. The red indicator light also comes on.

I have cleaned an vaselined the connections and moved the motor one from the motor side of its isolator to the battery side as recommended by Vic.

Could it possibly be that the VSR feeds the house battery via cables which came permanently attached of about 4 sq mm ( 140 amp model) while the paralling circuit is in about 60 sq mm cable?

If I cant sort this out I am back trying to remember to turn the paralling isolator on and off every time I start and stop the motor.

 

[davidej]

PS

As a comment to #10 and #11, I thought I was " improving " the system by paralling the two hi amp hr batteries for house duties and fitting a small one for the motor.

We would commonly only run the motor for about 10 mins to get off the mooring/ leave the marina and then do a 18-24 hr sail. Lights/ autopilot/ instruments would drain both batteries if (as occasionally happened ) I forgot to isolate one of them.

 

[Heckler]

People like to "upgrade" their systems .......... I did not say "improve" though!

Hee hee! sometimes simple is best.
Stu

 

[Heckler]

PS

As a comment to #10 and #11, I thought I was " improving " the system by paralling the two hi amp hr batteries for house duties and fitting a small one for the motor.

We would commonly only run the motor for about 10 mins to get off the mooring/ leave the marina and then do a 18-24 hr sail. Lights/ autopilot/ instruments would drain both batteries if (as occasionally happened ) I forgot to isolate one of them.

Ok, the widget is causing you grief, take it off, put back to Bene std then fit a solar panel to keep the start battery topped whilst you are away. A question that has to be asked is why are you worrying about the start battery? If it is in good condition, one start wont be flattening it and if you only have two house batteries, they wont last you long enough to go on an 18-24 hr sail with the fridge, autopilot, radio and instruments on without charging. My 381 is almost identical in electrical terms and needs my 256 watts of solar panel to keep my 3 or 4 110amp batteries in good fettle on passage.
We used to be on a pile mooring in Pwllheli, a 56 watt solar panel was more than adequate to keep the batteries topped up.
Stu

 

[Heckler]

The reason for starting this thread is that I don't think my alternator is charging the house battery properly, and I just can't diagnose the problem.

When I start the motor, the motor battery voltage immediately rises to about 14.0-14.1. The house battery voltage only rises to about 12.7 and then creeps up very slowly. If I close the isolator which I referred to in post #6 and which parallels up the two batteries, the house battery voltage also immediately rises to about 14.

I have checked the VSR (as far as I am able) by disconnecting the house battery connection and the voltage on it rises from zero to 14 when I start this motor. The red indicator light also comes on.

I have cleaned an vaselined the connections and moved the motor one from the motor side of its isolator to the battery side as recommended by Vic.

Could it possibly be that the VSR feeds the house battery via cables which came permanently attached of about 4 sq mm ( 140 amp model) while the paralling circuit is in about 60 sq mm cable?

If I cant sort this out I am back trying to remember to turn the paralling isolator on and off every time I start and stop the motor.

The paralleling link is big because it could take the whole load of starting, the vsr only has to carry charging or equalising current.
S

 

[Heckler]

The reason for starting this thread is that I don't think my alternator is charging the house battery properly, and I just can't diagnose the problem.

When I start the motor, the motor battery voltage immediately rises to about 14.0-14.1. The house battery voltage only rises to about 12.7 and then creeps up very slowly. If I close the isolator which I referred to in post #6 and which parallels up the two batteries, the house battery voltage also immediately rises to about 14.

I have checked the VSR (as far as I am able) by disconnecting the house battery connection and the voltage on it rises from zero to 14 when I start this motor. The red indicator light also comes on.

I have cleaned an vaselined the connections and moved the motor one from the motor side of its isolator to the battery side as recommended by Vic.

Could it possibly be that the VSR feeds the house battery via cables which came permanently attached of about 4 sq mm ( 140 amp model) while the paralling circuit is in about 60 sq mm cable?

If I cant sort this out I am back trying to remember to turn the paralling isolator on and off every time I start and stop the motor.

Am slowly getting my head around this. Where and how are you checking the voltage? To charge both banks you need both isolators switched on. It sounds as if you are starting and running on just the starter battery and not switching the house bank on? If so that will explain why you are getting different voltages. The house is at resting disconnected almost fully charged state, the start is at connected charging state. You are expecting the VSR to equalize and it , or not quickly enough. When you switch both banks on together the link I referred to equalises the charge and you see charge voltage applied to both banks! The batteries arent actually at 14 plus volts, that is just the surface charging voltage. If the house bank is showing 12.7v at rest then they are there or thereabouts fully charged. It takes forever to fully charge a nearly full battery and so because you are seeing a voltage which equals charging state you are expecting to see the same on the house which aint going to happen because of the above. Maybe the widget is doing its job!
Stu

 

[VicS]

My boat (Beneteau 361) has a large house battery and a separate smaller motor start battery, each with a different isolator and a single negative isolator.

The mains and small solar panel only charge the house battery.

The VSR is wired as recommended for a single sensing, ie with the red going to the motor side of its isolator. But it is actually a dual sensing and the recommendation for this is for the red to go to the battery side of the motor isolator.

Will this make any difference to the ability of the alternator to charge the house battery when the motor is running ? After all, in this situation the isolator is closed so both sides are at the same voltage.

The only difference, as I see it, is that when the mains charger raises the house battery voltage sufficiently to trigger the VSR, the motor battery would not get charge unless its isolator was closed.

Anybody got any thoughts on this?

Looking at this again I realise that you have wired it to different set of instructions to those which I downloaded


Wired with the red going to the switched side of the engine battery isolator means that it will only operate when the isolator is closed. The output from the solar and mains charging systems will only charge the house battery while the engine battery isolator is open although it will also charge the engine battery when the isolator is closed.

The alternator will of course charge both battery banks when the engine is running

If you change the connection to the battery side of the isolator it will operate regardless of the setting of the isolator. The mains and solar systems will always charge both battery banks. even if the engine battery isolator is closed. The alternator likewise, of course.

It would however be useful if you posted a link to the instructions you have/ are following. Then we'ed know we are singing to the same songsheet.

 

[pvb]

It would however be useful if you posted a link to the instructions you have/ are following. Then we'ed know we are singing to the same songsheet.

I'll second that! It would be good to know which model of BEP VSR the OP has. I was bewildered by his mention of the "cables which came permanently attached of about 4 sq mm ( 140 amp model)". Also useful to know whether he bought it new or whether it's an eBay bargain.

 

[Heckler]

Looking at this again I realise that you have wired it to different set of instructions to those which I downloaded


Wired with the red going to the switched side of the engine battery isolator means that it will only operate when the isolator is closed. The output from the solar and mains charging systems will only charge the house battery while the engine battery isolator is open although it will also charge the engine battery when the isolator is closed.

The alternator will of course charge both battery banks when the engine is running

If you change the connection to the battery side of the isolator it will operate regardless of the setting of the isolator. The mains and solar systems will always charge both battery banks. even if the engine battery isolator is closed. The alternator likewise, of course.

It would however be useful if you posted a link to the instructions you have/ are following. Then we'ed know we are singing to the same songsheet.

Have just checked my boat wiring diag which will be the same as the 361. The mains charger goes to both the battery sides of the the isolator, so when the mains is connected both banks charge even if they are switched off. The alternator goes to one of the banks on the OTHER side of the isolators ie the switched side. The link I refer to is on that side, SO both isolators have to be switched on to charge both banks from the alternator. If he, as I suspect, is keeping one of the isolators open then that bank will not be charging from the alternator giving the different voltages reported. That also means that if he has the VSR on the "wrong side" then depending on the isolator positions then he will be getting strange results.
Stu