Boat wiring - will this work?

[Balbas]

I'm getting threaders with the wiring on my boat. Put in by the previous owner, some of it is really well done, quite a lot is a rats nest. And it's all been done using non tinned wire and I'm getting bad connections alles uber der platz. Sometimes the engine starts really well, other times it's reluctant, and sometimes it doesn't want to know at all. There's nothing wrong with the engine, if I run jump cables to it, it'll go every time.

So I need to rewire the boat. Apologies for the (quite literally) on the back of an envelope diagram, but if I wired it as per the image* would it work? Is there anything I haven't considered? I assume that if I shut both battery switches I would have the effect of 'both' on the current 1-Both-2-Off switch?

*No I didn't go to art school and yes my wiring will be neater than my diagram drawing...

 

[simonfraser]

well, how much detail are we going to get into ....
1) you don't want your engine battery to be connected to anything else, its just for starting

 

[Balbas]

well, how much detail are we going to get into ....
1) you don't want your engine battery to be connected to anything else, its just for starting

get into as much detail as you like, I'm more than happy to learn. This boat, my first 'proper' boat (the wayfarer doesn't have a battery!) is currently wired so that everything works off both banks.

Wired by the previous owner, so I don't have an ego about it if its all wrong!!!

 

[lw395]

well, how much detail are we going to get into ....
1) you don't want your engine battery to be connected to anything else, its just for starting

That is my first thought, but then you need some means of connecting the alternator output to both batteries...

So, what's fundamentally needed perhaps is that the engine battery is not connected to anything else, 'except when the engine is running' or 'unless the batteries are charging'

This can be done with the switches pictured, as with a correctly programmed 1B2 switch operator. But some system of automating that with a VSR, fet switch, diode pack etc is more foolproof? If you're going to rely purely on manual switching, why not use a 1B2 switch as at least it's understood by lots of old timers?

In terms of cabling, my preference would be that the engine battery grounds directly to the starter motor or engine.

Re the bad connections and untinned cable. Unles the cable is actually corroding away along its lengh, the bad connections are probably due to poor crimping. And if battery cable is corroding that much, it's getting too wet too often.

 

[PaulRainbow]

I'm getting threaders with the wiring on my boat. Put in by the previous owner, some of it is really well done, quite a lot is a rats nest. And it's all been done using non tinned wire and I'm getting bad connections alles uber der platz. Sometimes the engine starts really well, other times it's reluctant, and sometimes it doesn't want to know at all. There's nothing wrong with the engine, if I run jump cables to it, it'll go every time.

So I need to rewire the boat. Apologies for the (quite literally) on the back of an envelope diagram, but if I wired it as per the image* would it work? Is there anything I haven't considered? I assume that if I shut both battery switches I would have the effect of 'both' on the current 1-Both-2-Off switch?

*No I didn't go to art school and yes my wiring will be neater than my diagram drawing...

This might be better ;

 

[Balbas]

That is my first thought, but then you need some means of connecting the alternator output to both batteries...

So, what's fundamentally needed perhaps is that the engine battery is not connected to anything else, 'except when the engine is running' or 'unless the batteries are charging'

This can be done with the switches pictured, as with a correctly programmed 1B2 switch operator. But some system of automating that with a VSR, fet switch, diode pack etc is more foolproof? If you're going to rely purely on manual switching, why not use a 1B2 switch as at least it's understood by lots of old timers?

To be honest, I was intending to keep it simple (and cheap!) but replace the (universally hated?) 1-B-2 switch. I'd be more than happy to keep it, but as I'm re-running the main cabling, now would be the time to change it. OK then, any suggestions for a good VSR and suggestions for isolators that are recommended?

In terms of cabling, my preference would be that the engine battery grounds directly to the starter motor or engine.

I suggested this in a previous thread - I was going to do exactly that, but I seem to remember that I was told it was unnecessary.

Re the bad connections and untinned cable. Unles the cable is actually corroding away along its lengh, the bad connections are probably due to poor crimping. And if battery cable is corroding that much, it's getting too wet too often.

Well to be honest I'm guessing as to what my issue is, although it's definitely bad connections. The boat had sat for 3 years prior to me getting her and had leaky windows and a full bilge so...

This might be better ;

That is a lot better, thank you.

 

[lw395]

To be honest, I was intending to keep it simple (and cheap!) but replace the (universally hated?) 1-B-2 switch. I'd be more than happy to keep it, but as I'm re-running the main cabling, now would be the time to change it. OK then, any suggestions for a good VSR and suggestions for isolators that are recommended?


I suggested this in a previous thread - I was going to do exactly that, but I seem to remember that I was told it was unnecessary.
Well to be honest I'm guessing as to what my issue is, although it's definitely bad connections. The boat had sat for 3 years prior to me getting her and had leaky windows and a full bilge so...

....

In the bigger cable sizes I wouldn't get too excited about tinned or not.

VSR is not that expensive, but it's all cash that could be spent on beer or sails. I don't like to tell others how to spend their cash.

Having had a boat where the elctrics got a tad complex due to repeated piecemeal additions, one of my criteria for a 'good' system is that it's simple enough (to use) that I can lend my boat to someone who isn't an electrical engineer with just a few simple instructions. I feel your orignal diagram may fail that test, and a VSR or B2B charger might help.

Paul's diagram is good, but you might want an alternator with that? One can debate exactly where it should be connected. Directlly to the house battery has some merits.

 

[dunkelly]

why is it that the 1b2 switches are not a good solution anymore , is it just that technology has overtaken them or is there something inherently wrong with them ? serious question from an ole timer

 

[Balbas]

In the bigger cable sizes I wouldn't get too excited about tinned or not.

VSR is not that expensive, but it's all cash that could be spent on beer or sails. I don't like to tell others how to spend their cash.

Having had a boat where the elctrics got a tad complex due to repeated piecemeal additions, one of my criteria for a 'good' system is that it's simple enough (to use) that I can lend my boat to someone who isn't an electrical engineer with just a few simple instructions. I feel your orignal diagram may fail that test, and a VSR or B2B charger might help.

Paul's diagram is good, but you might want an alternator with that? One can debate exactly where it should be connected. Directlly to the house battery has some merits.

Right then, so if I ran some of this https://www.12voltplanet.co.uk/CABSCBATXFLX50PNT.html

With some of these https://www.12voltplanet.co.uk/copper-tube-terminal-50mm-max-cable.html

To some of these https://www.12voltplanet.co.uk/positive-power-distribution-post-large-base-8mm.html

Used my current 1-B-2 switch but added one of these https://www.12voltplanet.co.uk/voltage-sensitive-relay-12v-140a.html

Then I would have a sensible, functioning system? If that's the case, I'll order the bits tonight and spend a day this weekend getting it squared away.

 

[PaulRainbow]

Paul's diagram is good, but you might want an alternator with that? One can debate exactly where it should be connected. Directlly to the house battery has some merits.

It's on the engine, that particular diagram is pretty basic and assumes the alternator is connected to the starter, hence only one battery sized cable to the engine. Pretty sure that's how the OPs is at the moment, i'd leave it there, if the VSR failed the engine battery still gets charged.

 

[lw395]

If going the VSR route, I think it's more coherent to lose the 1B2 switch.

Then you can connect theengine battery to the engine. The house battery to everything else. Two isolators which can be 'on' whenever you're aboard and everything happens automatically.

A third switch for jump starting from the house battery.


Of course this requires buying 3 battery isolator switches and filling the damned great hole where the 1B2 used to be.

I'm not familiar with the particular VSR you show.

 

[Balbas]

It's on the engine, that particular diagram is pretty basic and assumes the alternator is connected to the starter, hence only one battery sized cable to the engine Pretty sure that's how the OPs is at the moment at the moment, i'd leave it there, if the VSR failed the engine battery still gets charged.

That's a point actually - the starter motor obviously has a great big fat + cable going to it. But there is also a fat(ish) cable going from the same + terminal on the starter to the back of the alternator. Presumably this is the path the charge takes to get from the alternator into the battery?

Never really thought about it before.

 

[lw395]

It's on the engine, that particular diagram is pretty basic and assumes the alternator is connected to the starter, hence only one battery sized cable to the engine Pretty sure that's how the OPs is at the moment at the moment, i'd leave it there, if the VSR failed the engine battery still gets charged.

Yes, makes sense, just needs to be in there explicitly.

 

[PaulRainbow]

Right then, so if I ran some of this https://www.12voltplanet.co.uk/CABSCBATXFLX50PNT.html

With some of these https://www.12voltplanet.co.uk/copper-tube-terminal-50mm-max-cable.html

To some of these https://www.12voltplanet.co.uk/positive-power-distribution-post-large-base-8mm.html

Used my current 1-B-2 switch but added one of these https://www.12voltplanet.co.uk/voltage-sensitive-relay-12v-140a.html

Then I would have a sensible, functioning system? If that's the case, I'll order the bits tonight and spend a day this weekend getting it squared away.

Yes, but.......

If the cable is likely to be in a damp place, consider tinned, otherwise it's OK.

Not sure why you need the terminal posts, but if you do need them, those are fine.

A VSR is OK, but i'd fit a Victron one, only another £9. Connect it between the batteries as shown in my diagram, but note, if the connection to the domestic battery could possibly chafe and short, fit a fuse in that cable, close to the battery. Keep the cables short (VSR as close to batteries as possible and 10mm will be OK (the black wire can be 1.5mm) and fit 70a midi fuses.

Three of these would be better than the 1-2-B, wired as above, but if you're happy to keep the 1-2-B that's your call.

https://www.12voltplanet.co.uk/marine-battery-isolator-switch-2-positions.html

 

[PaulRainbow]

That's a point actually - the starter motor obviously has a great big fat + cable going to it. But there is also a fat(ish) cable going from the same + terminal on the starter to the back of the alternator. Presumably this is the path the charge takes to get from the alternator into the battery?

Never really thought about it before.

It is, i'd leave that as it is. The VSR will take care of charging the domestic battery.

 

[PaulRainbow]

Yes, makes sense, just needs to be in there explicitly.

If it was an installation where the alternator was wired separately, it would be.

 

[Balbas]

Thanks chaps. My boat always seems to be a *bit* damp, but then I'm after a reasonably quick fix at the moment, so may just do it with the normal wire and re-do it all again in say 5 years, or as I decide to add solar etc. Sounds wasteful, but the reality is I won't bother unless I start having problems again... And I may have sold the boat or had to re-engine her by then, so...

The reason for the terminal posts is because all of the wiring is a bit shoddy and it makes sense to run new battery cabling as far as I'm planning to, so if I put in the new posts at that stage, then I can swap over the remaining (domestic, electronics etc) wiring and just work through it all in slow time - but knowing that its all good as far as the posts.

Question on the VSR, you mention that it should be as close to the batteries as possible. Engine battery is under the starboard side berth and domestics are under the port side berth. Advice in that scenario? Don't say 'move the battery...'

 

[Balbas]

why is it that the 1b2 switches are not a good solution anymore , is it just that technology has overtaken them or is there something inherently wrong with them ? serious question from an ole timer

Sorry missed this. I'm told that they can be mis managed (and indeed I used to mis manage mine), leaving you with a flat starting battery and flat domestic battery. What I used to do was start on engine, but then immediately switch to both to charge domestic and engine up. But by doing that I was risking one bad battery bringing the lot down.

 

[prv]

What I used to do was start on engine, but then immediately switch to both to charge domestic and engine up. But by doing that I was risking one bad battery bringing the lot down.

Or, more to the point, forgetting to turn it back from "both" to "domestic" when you start sailing and stop the engine, and then running both batteries down together.

And, even if you have heavy-duty OCD and always sail alone and can be certain that the manual switch will always be operated correctly - why give yourself the extra chore? A VSR does exactly the same job all on its own and lets you stay on deck and enjoy the sailing. What's not to like?

Pete

 

[superheat6k]

Nothing at all wrong with 0-1-both-2-0 switches (IMHO of course), but you do need a brain it operate it properly (although similar I understand to the same brain required to operate the sails, navigate (without GPS !), engine start switch , etc., I recall, but sadly not so commonly available aboard boats nowadays apparently !).