1/2/Both switch bust?

richardabeattie

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Please don't shoot me for having a 1/2/B.

This morning I brought just one battery to the boat to start the engine to move out to my berth. I put it into one of the two battery spaces. The cables to the empty space were left disconnected. All went well and everything worked - but it all continued to work irrespective of whether the switch was turned to 1 or 2 or both. Surely either position 1 or 2 should have switched everything off?
 
Please don't shoot me for having a 1/2/B.

This morning I brought just one battery to the boat to start the engine to move out to my berth. I put it into one of the two battery spaces. The cables to the empty space were left disconnected. All went well and everything worked - but it all continued to work irrespective of whether the switch was turned to 1 or 2 or both. Surely either position 1 or 2 should have switched everything off?

Depends how it's wired. Conventionally you are right, but I have heard of people using the 1-2-B just to distribute the charge.
 
Please don't shoot me for having a 1/2/B.

This morning I brought just one battery to the boat to start the engine to move out to my berth. I put it into one of the two battery spaces. The cables to the empty space were left disconnected. All went well and everything worked - but it all continued to work irrespective of whether the switch was turned to 1 or 2 or both. Surely either position 1 or 2 should have switched everything off?

If it is supposed to select either, or both, of two batteries then something is wrong. Did it switch every thing off if turned to the off position ?

I dont suppose you know what would have happened if you'd put the battery in the other position
 
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What a brilliant opportunity to sort out the wiring and get rid of the 1-2-Both switch!

Perhaps an idea worth considering if the OP is considering significant modifications to the electrics otherwise just replacing the switch, if it is indeed defective, is all that is required. No need to fix what's not broken

Many people happily use a 1,2 both switch and do not share your bias against them.
 
Many people happily use a 1,2 both switch and do not share your bias against them.

"Bias" is a rather harsh word, isn't it? It has implications of unfairness, which isn't justified. 1-2-Both switches are old technology, a cheap solution which has lots of potential for mistakes, possibly leading to inability to start the engine. There are much better ways of switching batteries, which is why today's boat manufacturers generally avoid 1-2-Both switches.
 
Yes - switching to off turned everything off. I think I can live with it as it is.

No, you need to investigate the wiring. Your original post suggested that the switch isn't isolating the batteries correctly. You run the risk of ending up with a flat starter battery and a visit from the RAC.
 
Perhaps you're still trimming wicks on paraffin lamps?

That's why we have electric lights........ so we can see to do it properly. I expect JD uses a candle though.

The next thing you'll be suggesting is LEDs instead of tried and tested incandescent filament bulbs.
 
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This morning I brought just one battery to the boat to start the engine to move out to my berth. I put it into one of the two battery spaces. The cables to the empty space were left disconnected. All went well and everything worked - but it all continued to work irrespective of whether the switch was turned to 1 or 2 or both. Surely either position 1 or 2 should have switched everything off?
Sounds very odd, if the battery was in position 1 then everything should have worked with the switch in position 1 and vice versa.

Clearly a multimeter is needed to check stuff.

Personally, I am a huge fan of 1-both-2-off switches as they are simple, flexible and pretty bomb proof; it is the people who use them that are usually the problem.
 
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The next thing you'll be suggesting is LEDs instead of tried and tested incandescent filament bulbs.

Every light source on my boat is LED except the compass light (haven't found an LED one), the chart light (ditto) and the fluorescent tube over the galley (my fitting held the Boatlamps LED "tube" at a silly angle to I had to return it.
 
If you have two matching batteries, a very simple setup and don't mind messing around trying to remember which battery you should be charging, then 1-2-B switches work OK.

I have a single battery for starting my engine and 3 x 130ah batteries for domestics. Why would i want to select the single engine battery and run the whole boat from that ? I'm not alone, a great many cruising boats now have a lot of electrics, which require several batteries, the engine still only needs a single battery. Wiring such boats to a 1-2-B switch would be madness.
 
Every light source on my boat is LED except the compass light (haven't found an LED one), the chart light (ditto) and the fluorescent tube over the galley (my fitting held the Boatlamps LED "tube" at a silly angle to I had to return it.

My compass now has red "grain of rice" LEDs in it :encouragement:
 
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