Moving from 1,2,Both switch to VSR

[Refueler]

This topic seems to be endlessly discussed with no clear conclusion.

Sea Start tell me that they like the simple 1-2-1+2-OFF switch - a more complex solution makes faults harder to trace.

Incidentally,, I once had a wiring fault which took to output from the alternator - 30 A alternator on Yanmar 1GM10 - intermittent open circuit - the alternator still works, although you might not be so lucky.

I am told by guys who service alternators / starters etc. over here that some modern alternators have a 'safety' built in to avoid blowing diodes when someone switches off ... but they also say - DON'T rely on it !!

 

[LittleSister]

I think that it is pointless to have a 1-2-Both switch if you're going to have a VSR.

You want separate domestic and engine circuits, each with their own isolator switch, linked only by the VSR and an emergency manually operated link switch. (Note that the Cyrix VSR has an electrically operated 'emergency link' facility (i.e. operating the relay regardless of the voltage sensing), eliminating the need for a third high current capable switch.)

The trouble with the dual circuit plus switch is that although you can use it to parallel the batteries you cannot use it to run on one battery leaving a dead battery isolated .......... unless you physically disconnect the dead battery or have some other form of local isolation

I am reluctant to contradict someone as knowledgeable and helpful as VicS, but I believe he is mistaken if he is saying that the engine and domestic isolator switches in a VSR set up cannot isolate a dead battery. It depends on how the switches are wired. It think is true that the way the Blue Sea switches are wired as standard do not allow this (it is a particular beef of Paul Rainbow IIRC) , but they can easily be rewired.

 

[laika]

Are they all wired in the same regardless of boat?

As others have focused on the other parts of the question I'll just make a comment on the easy part.

"no"

Never assume what the 1-2-both switch does on a new-to-you boat. That it is wired "correctly" as described above is probably a fair assumption on a charter or school boat but not a private one. My 1-2-both had been re-wired to accommodate a split diode charger . It was subsequently re-wired to incorporate a VSR with the 1-2-both switch effectively just being a complicated on-off switch.

I definitely don't want to disagree with anyone regarding capabilities of the bluesea vsr but one thing high on my "to do" list is re-wiring for manual battery combination capability. The bluesea won't charge your house bank if it's below a certain voltage. Actually as I'm writing that and remembering the "how I know" story, perhaps I should also look into seeing if the AP's low voltage alarm can be raised to *above* that point. Mucking about with battery cables in channel chop is less fun than a simple switch.

 

[PaulRainbow]

I think that it is pointless to have a 1-2-Both switch if you're going to have a VSR.]/quote]

Adding a VSR to a 1-2-B installation does have some advantages. Connect the VSR across the batteries, either at the batteries or at the switch. This means that all batteries get charged when the engine is running, irrespective of the switch setting. No need to fiddle with the switch to get the batteries charged. Two choices ;

1. Start the engine on the starter battery, then turn to the domestic bank, straight away.
2. Use the "domestic" bank for everything, leaving the smaller, single battery, for emergencies.

Not my favourite setup, but it is better than the standard 1-2-B arrangement, but still inferior to separate switches. It does require a dual sensing VSR, if a unidirectional VSR was used the alternator output would need to be connected directly to the engine battery, in which case it should be fused. I'd fit a dual sensing VSR.

You want separate domestic and engine circuits, each with their own isolator switch, linked only by the VSR and an emergency manually operated link switch. (Note that the Cyrix VSR has an electrically operated 'emergency link' facility (i.e. operating the relay regardless of the voltage sensing), eliminating the need for a third high current capable switch.)

Was with you on the first sentence John, but..... The Victron "Start Assist" feature might start the engine if the battery was partially discharged, but other than that, i think it's a pointless gimmick, as much as i favour the Cyrix.

It can only carry the rated current of the VSR, usually 120a for the boats discussed here, so it would be unlikely to start an engine if the battery was flat and most certainly not if the battery had failed. So, you'd still need that third switch. The third switch can simply be turned on for a "jump start", or you can isolate a dead battery then turn on the emergency switch to allow everything to run from one battery/battery bank.

I am reluctant to contradict someone as knowledgeable and helpful as VicS, but I believe he is mistaken if he is saying that the engine and domestic isolator switches in a VSR set up cannot isolate a dead battery. It depends on how the switches are wired. It think is true that the way the Blue Sea switches are wired as standard do not allow this (it is a particular beef of Paul Rainbow IIRC) , but they can easily be rewired.

Some of the off the shelf switch clusters, notably BEP, are fitted with links that connect the emergency switch to the battery side of the two main switches. So, if (for example) the engine battery has failed, you turn the engine isolator off, this disconnects the engine battery from the engine circuits, safely isolating the battery. You now turn on the emergency switch, this connects the engine and domestic batteries together in parallel, most likely pulling the domestic batteries down, or if the fault is a shorted cell the engine battery is now being boiled by the domestic bank, expect a load bang if you create a spark near the batteries. Not only that, the engine circuits are still not connected to a power source.

If the links are connected to the load side of the switch, when you isolate the dead battery it's still safely taken out of circuit, but when you turn the emergency switch on, the domestic circuits and the engine circuits are connected in parallel, so everything works correctly.

 

[graham]

Charging two battery banks - Practical Boat Owner

 

[Arcady]

I fail to see how you're going to use a 1-2-Both switch as well as a VSR ...

Easy. On my last two boats the VSR handles the charging requirements, The domestic bank has a simple on/off switch and the 1-2-Both switch simply determines which battery Is used for engine starting. It has nothing to do with which batteries get charged. So far I’ve found this pretty foolproof ...

 

[PaulRainbow]

Wiring a VSR with the 1-2-B switch, note the VSR is dual sensing in both installations.

Three separate switches, with the VSR.

 

[VicS]

I am reluctant to contradict someone as knowledgeable and helpful as VicS, but I believe he is mistaken if he is saying that the engine and domestic isolator switches in a VSR set up cannot isolate a dead battery. It depends on how the switches are wired. It think is true that the way the Blue Sea switches are wired as standard do not allow this (it is a particular beef of Paul Rainbow IIRC) , but they can easily be rewired.

I think you misunderstand

The point I was trying make was purely about the Blue Sea "dual circuit" and " dual circuit plus " switches . Not about separate isolator switches and a VSR

The dual circuit switch switches both batteries on simultaneously.........(Saves the idle skipper having to operate two switches when it can be done with one)
"plus " version also has the facility to parallel the batteries.

They do not allow you to switch just one battery on and leave a failed battery isolated as can be done with 2 separate isolators and an emergency crossover switch, or with a 1,2 both switch for that matter


I think your last sentence refers to the BEP VSR/ switch clusters, not to the Blue Sea battery switches

 

[LittleSister]

I think you misunderstand

The point I was trying make was purely about the Blue Sea "dual circuit" and " dual circuit plus " switches . Not about separate isolator switches and a VSR

The dual circuit switch switches both batteries on simultaneously.........(Saves the idle skipper having to operate two switches when it can be done with one)
"plus " version also has the facility to parallel the batteries.

They do not allow you to switch just one battery on and leave a failed battery isolated as can be done with 2 separate isolators and an emergency crossover switch, or with a 1,2 both switch for that matter


I think your last sentence refers to the BEP VSR/ switch clusters, not to the Blue Sea battery switches

My apologies. (And yes you're right, I did confuse BEP with Blue Sea.)

 

[geem]

For us as liveaboards a VSR is not a good solution. We spend most of our time at anchor. Every night our domestic batteries are depleted such that they need charging each following day by solar. The bulk and absorption phase of domestic bank charging takes a total of approximately 6 hours until the batteries hit float. If we use a VSR the engine battery( that has had no discharge over night) gets a needless aggressive charge on a full battery. I cant believe this is good for my engine battery. Instead, the engine battery has a dedicated small solar panel that we set the MPPT regulator to a far less aggressive charge cycle, such that we are just floating the battery. This is optimum for long battery life.

 

[PCUK]

No need for a solenoid - a simple on/off switch does the job.

Yes, but we are talking about people who forget which position the switch is in so a solenoid makes it impossible to leave the batteries permanently connected.

 

[pvb]

Yes, but we are talking about people who forget which position the switch is in so a solenoid makes it impossible to leave the batteries permanently connected.

Further proof, if proof is needed, of the folly of having a 1-2-Both switch!

 

[halcyon]

They're in the business of fixing boats, not enjoying the use of boats. The biggest drawback of the 1-2-Both switch (apart from frying the alternator if you turn the switch off accidentally) is having to keep changing the switch setting, with the associated risk of leaving it on the wrong setting and flattening the start battery - which I suppose is where Sea Start get involved. Just having two simple on/off switches and a VSR (or low-loss splitter) makes for the easiest possible operation. Arrive at the boat, turn both switches on, use the boat, then turn both switches off when you leave the boat. No risk of a flat starting battery. No risk of a well-meaning crew member messing up the 1-2-Both switch setting.

What I find odd is that we discuss the same point time and time again, I only introduced a VSR 40 years ago, read the 1982 literature the reason then is the same today.

Brian

 

[geem]

What I find odd is that we discuss the same point time and time again, I only introduced a VSR 40 years ago, read the 1982 literature the reason then is the same today.

Brian

The point is they work for some people but not everybody sees them as an advantage. You are only looking at the issue from your own perspective. I bought one, installed it, then removed it as I saw it as a disadvantage. We don't all use our boats in the same way

 

[Graham376]

The point is they work for some people but not everybody sees them as an advantage. You are only looking at the issue from your own perspective. I bought one, installed it, then removed it as I saw it as a disadvantage. We don't all use our boats in the same way

1,2, both works fine for us for reasons you've given in #30. We don't have crew to worry about getting things wrong and the switch is less likely to fail than anything containing relays and/or software. I don't understand worries about engine battery charging and wonder if people put their car on charge if not used for a few days.

 

[Poey50]

The point is they work for some people but not everybody sees them as an advantage. You are only looking at the issue from your own perspective. I bought one, installed it, then removed it as I saw it as a disadvantage. We don't all use our boats in the same way

Another way to go instead of a VSR is an alternator to battery charger giving a boost charge to the house bank and an unboosted maintenance charge to the engine battery. I use that with separate house and engine switches and emergency linking switch. Very simple, and effective in getting the most out of my otherwise dumb alternator.

 

[BabaYaga]

For us as liveaboards a VSR is not a good solution. We spend most of our time at anchor. Every night our domestic batteries are depleted such that they need charging each following day by solar. The bulk and absorption phase of domestic bank charging takes a total of approximately 6 hours until the batteries hit float. If we use a VSR the engine battery( that has had no discharge over night) gets a needless aggressive charge on a full battery. I cant believe this is good for my engine battery. Instead, the engine battery has a dedicated small solar panel that we set the MPPT regulator to a far less aggressive charge cycle, such that we are just floating the battery. This is optimum for long battery life.

Good point and I think that the same mechanism is at work for many coastal marina hoppers, with the difference that the aggressive (and from the starter battery's point of view, totally unnecessary) charging is taking place during nighttime, through the mains charger.

 

[halcyon]

I am told by guys who service alternators / starters etc. over here that some modern alternators have a 'safety' built in to avoid blowing diodes when someone switches off ... but they also say - DON'T rely on it !!

They fitted a avalanche diodes ( zener diode ), or Lucas did, to alternators in the mid 1970's to protect rectifier diodes.

The 1, 2, both switch, all depends on the owner / operator as to what they prefer, in the old days builder's preferred a VSR as it reduced the chance of a owner operating error and complaint of flat batteries.

Brian

 

[Poey50]

Good point and I think that the same mechanism is at work for many coastal marina hoppers, with the difference that the aggressive (and from the starter battery's point of view, totally unnecessary) charging is taking place during nighttime, through the mains charger.

See my reply above on the A2B charger. My mains charger is then only connected to the house bank.

 

[halcyon]

For us as liveaboards a VSR is not a good solution. We spend most of our time at anchor. Every night our domestic batteries are depleted such that they need charging each following day by solar. The bulk and absorption phase of domestic bank charging takes a total of approximately 6 hours until the batteries hit float. If we use a VSR the engine battery( that has had no discharge over night) gets a needless aggressive charge on a full battery. I cant believe this is good for my engine battery. Instead, the engine battery has a dedicated small solar panel that we set the MPPT regulator to a far less aggressive charge cycle, such that we are just floating the battery. This is optimum for long battery life.

All depends on the VSR you fit, you can avoid your problem.

But as I say #38, it is what suits the owner.

Brian