Confused battery set up. Two batteries in parallel.

[Humblebee]

Normal set up. The engine start and the cabin light instruments all come from the same battery. You just have a choice which you use. I , 2 or both.

I've put in bold a bit I don't understand. Certainly, two batteries wired in parallel are in effect one large battery, but I always thought that this large battery - call it the domestic battery - was separate from another - the starter battery - unless the switch was in the both position. In other word, position 1 (let's say) connected the domestic battery to the domestics and starter, independent of the starter battery, position 2 connected the starter battery to domestics and starter, independent of the domestic battery, both connected starter and domestic batteries to starter and domestic circuits and off disconnected all batteries. Position Both, I think, should be used only for charging all batteries together, or, if necessary, giving extra oomph to the starter if the starter battery is low.
Can someone please keep me right? Ta.

 

[pvb]

And people keep saying 1-2-Both switches are simple.....

 

[peteK]

They are if you understand electrics the problem is most dont and therefore an automatic system is better.

 

[pvb]

They are if you understand electrics the problem is most dont and therefore an automatic system is better.

You'll be branded as a heretic!

 

[greeny]

Here we go again.
Anyone up for an anchor thread?

 

[RichardS]

I'm just here to answer questions, any questions, so bring 'em on.

Richard

 

[James_Calvert]

I'm just here to answer questions, any questions, so bring 'em on.

Richard

The OP has a Westerly Centaur.

I expect he'll be wanting some advice on headlining droop soon.

Ready for it?

 

[RichardS]

The OP has a Westerly Centaur.

I expect he'll be wanting some advice on headlining droop soon.

Ready for it?

I've owned several Land Rover / Range Rover models. When it comes to drawing pins, I've got a stock of all colours.

Richard

 

[RupertW]

I actually prefer 1 2 both switches for boats even though i am electrical engineer, They are fool proof if done correctly whereas other voltage select relays etc can give trouble. Aux batteries for mobile homes and vans can benefit from different arrangements.

The OP more ever has a 1 2 switch and merely needs to know how it works not what arcane peice of kit could replace it.

Any two battery system should be parallel on the negative but separate on positive so if the OP has paralleling on positive either there is a third battery or something very wrong, The OPs description of using match a correctly set up 1 2 switch with merely poor or flattish batteries, thus I suspect paralleling only in the both position

I like 1-2-B switches too because I’ve a degree in electrical engineering. It’s silly but fun having one, like having sails instead of an engine, and you can control your batteries much more precisely and idiosyncratically. But having a 1-2-B switch if you are not an electrical nerd is like having a Stuart Turner engine if you are not an engine nerd.

 

[James_Calvert]

I've owned several Land Rover / Range Rover models. When it comes to drawing pins, I've got a stock of all colours.

Richard

That's interesting. Seriously I have a 25 Yr old Volvo with the problem, currently held at bay with bits of bamboo.

Drawing pins? Do they come in grey?

 

[RichardS]

That's interesting. Seriously I have a 25 Yr old Volvo with the problem, currently held at bay with bits of bamboo.

Drawing pins? Do they come in grey?

You can get almost any colour on eBay although I'm not sure about grey. You could choose the nearest colour (dull white) or even paint them grey.

Obviously it has to be the same headlining that Land Rover use where the material is glued onto a hardboard-like backing panel and the glue gives up the ghost after 15 years.

Richard

 

[James_Calvert]

Yes it's like the Land Rover but about 23 years rather than 15...

To think I used to laugh at Westerly droop: having a Sadler which doesn't suffer.

 

[lw395]

First, I would suggest that Battery 2 might well have reached it's End Of Life, so needs replacing.

....

I see no evidence that it doesn't simply need charging.
Battery 1 dragged it up to 12.2V.

 

[lw395]

Here I would agree with any advice you gave about throwing away the 1-2-B switch. My guideline is that anybody who has to ask a question about a 1-2-B switch shouldn’t have one. Instead simple isolator switches and a VSR circuit should be fitted instead.

1-2-B switches are for electrical nerds only, and even then only if they are not absent minded ever.

Whatever system people have, they need to understand it.
Once upon a time, 1B2 switch systems were so simple that everyone knew where they stood.
These days, most people have a solar panel and there are variations.
With VSRs and isolator systems there are more variations and many possibilities for people to not know exactly how their boat is configured.
It's surprising that so many people get away with not knowing how their boats work really.

 

[ghostlymoron]

Good point.

They are only in parallel when the switch is at Both.

Otherwise one and/or the other is disconnected.

Not so. If they're connected together positive to positive you effectively have one battery whatever the position of the 1 2 B switch.
You need to trace your wiring so you know what's what only then can you make any changes. I'd recommend a VSR so you don't risk flattening both batteries (which WILL happen sooner or later)

 

[RupertW]

Whatever system people have, they need to understand it.
Once upon a time, 1B2 switch systems were so simple that everyone knew where they stood.
These days, most people have a solar panel and there are variations.
With VSRs and isolator systems there are more variations and many possibilities for people to not know exactly how their boat is configured.
It's surprising that so many people get away with not knowing how their boats work really.

I think for most people there is no need to understand an engine or your electrics or your plumbing - you just need systems as foolproof as possible, and a few fool rules to avoid problems. In other wordsrules that anyone knowledgeable can ignore but most will stay safe by adhering too. I’m not an engine person at all so am glad that engines are a lot more reliable and forgiving than they used to be. Mostly you just need a simple user manual for all boat systems (like on a charter boat) not a maintenance manual let alone be able to fix things.

So a natural hobbyist picks the systems they want to understand and ignores the rest. Electrics do it for me but I’ve reluctantly had to get good at plumbing, but gel coat fixing and winch maintenance have been avoided for a decade so far along with other preventative maintenance that other people wrongly think is essential. Anything which can be ignored for 10 years isn’t essential but could leave me with big bills in another 10 I suppose.

 

[PaulRainbow]

I think for most people there is no need to understand an engine or your electrics or your plumbing - you just need systems as foolproof as possible, and a few fool rules to avoid problems. In other wordsrules that anyone knowledgeable can ignore but most will stay safe by adhering too. I’m not an engine person at all so am glad that engines are a lot more reliable and forgiving than they used to be. Mostly you just need a simple user manual for all boat systems (like on a charter boat) not a maintenance manual let alone be able to fix things.

Sorry, you'll need to delete this post, it's far too sensible to be in a 1-2-B thread ?

But, as it's here and it's so sensible, i'll risk a reply.

There are those with 1-2-B switches who clearly love them and enjoy fiddling around with switches. They no doubt understand how they need to operate them and appreciate any risks that they would be subjected to if they misuse the switch. Some have apparently been using them for centuries without any problems

I work on a lot of boats and as i'm always kicking around marinas i meet a lot of owners. The vast majority of them are reasonably intelligent, at the very least. Many of them are in business of one sort or another and very succesful at what they do. Many are not mechanically or electrically orientated and such things are, to them, as alien as brain surgery and rocket science are to the rest of us. If i open the lid on the electics cupboard i can see, in a short time, what's going on amongst the rats nest of wiring that invariable resides therin. They just see a rats nest and their eyes glaze over.

The OP is a good example. With the greatest respect, he hasn't got a clue how his system works, or even how to properly describe what he thinks he sees. He's far from alone when it comes to electrics and i genuinely mean no disrespect to him, or anyone else that's confused by these things.

If he had two on/off switches, one marked "engine" and one marked "domestics", he would instantly know what they were and how they operated, they are intuituve to everyone above the age of about three. Everyone knows what a switch does, without explanation, three year olds know how to turn the lights on, or the X-Box.

Add a split charging system, suitable for the particular boat and it's other equipment/charging sources and he has nothing to do, but turn a switch or two on. He doesn't need to know, on a day to day basis, what's in the cupboard or what magical goings on happen there. He doesn't even need to know, on a day to day basis, what the "emergency" switch is for, or how it could be used, so long as he know to leave it off under normal circumstances. The operating manual can explain what to do in an emergency, although i find most people quickly grasp the concept of it being a "jump start" switch, for use in the event of a flat battery.

Your charter boat analogy is a good one. Most boat owners just want to use their boats, they are happy to learn which bits of string to pull, but have no interest in learning how things work, other than those things needed for normal operation.

I think there are times when too many people here think all boat owners live in PBO World. They don't.

 

[lw395]

I think for most people there is no need to understand an engine or your electrics or your plumbing - you just need systems as foolproof as possible, and a few fool rules to avoid problems. ....

When the smoke starts coming out, it's beyond 'useful' to know whether the battery isolator actually isolates the battery from ALL the wiring.
When a battery mysteriously goes flat at sea, somebody on board needs to know the system or at least have access to that knowledge.
Because boats are rarely standard, you can't even phone a mate who has the manual or look it up on the net.

There's less point understanding the finer points of the engine, beyond changing fuel filter and bleeding the system, because if it does go wrong, you just sail or anchor and you won't have the bits to fix much anyway.

The plumbing, well I seen enough go wrong on yachts to think people should know where all the seacocks are, what all the valves do and the basic layout.
I was once on a nice yacht, it had some complex retrofitted plumbing for a holding tank. There was a diagram attached, but the diagram was able to be interpreted more than one way. The YM aboard disagreed with my interpretation and got sprayed with shit for his sins.

A yacht is supposed to be capable of sailing the seas with a certain degree of self sufficiency. That means knowing how it works.
To a greater or lesser degree depending on how far from 'experts' you want to go.

 

[LadyInBed]

If he had two on/off switches, one marked "engine" and one marked "domestics", he would instantly know what they were and how they operated, they are intuituve to everyone above the age of about three. Everyone knows what a switch does, without explanation, three year olds know how to turn the lights on, or the X-Box.

Paul, aren't you jumping into your own hole here?
Two separate switches is IMO worse than a 1-2-B as after starting the engine the chances of switching the engine battery off before switching on the house is quite high. OK, you will say turn on the house before turning off the engine switch. Well isn't that the same as a 1-2-B with 1 and 2 labeled engine and house?

 

[pvb]

Two separate switches is IMO worse than a 1-2-B as after starting the engine the chances of switching the engine battery off before switching on the house is quite high. OK, you will say turn on the house before turning off the engine switch. Well isn't that the same as a 1-2-B with 1 and 2 labeled engine and house?

You haven't understood. With two separate on/off switches you just arrive at the boat, turn them both on, use the boat, then turn them both off when you go home. There's absolutely no need to fiddle with the switches. It's so much easier than a 1-2-Both switch, and there's no risk of accidentally flattening the engine battery.