What circuits to connect to engine batteries

[boater123]

I am currently fitting out a sail away widebeam and have begun my first fit of electrics.
Is it correct to connect the; headlamp, nav lights, horn, water pump and bathroom bilge pump to the engine battery or is it best practice to connect them to the leisure batteries.

Any guidance would be appreciated.

 

Thanks

[WotEver]

Hi Boater,

 

Everything except the starter motor should go to the leisure batteries (via an isolator of course)

 

Tony

[Tony Brooks]

Is that an actual bathroom bilge pump or a shower pump. The reason I ask is because those shower pumps that use a bilge pump in a box are known for leaking and clogging. If you have a bilge under the shower to pump shower water from I fear it could lead to smells in hot weather.

 

My opinion only. The engine battery is separated from the domestics so that whatever happens to the doemstic bank you can always start the engine to recharge so you need to minimise the loads on the engine battery.

 

I wire the horn via the ignition switch so it can not be accidental blown when you are tied up with the engine off so that means fed from the engine battery.

 

The tunnel lamp could be treated in the same way but it may be pushing the switch contacts a bit. Maybe use a relay. This will prevent you leaving it on when the engine is off. I think mine works fine without a relay but time will tell.

 

Water pump and shower pump definitely form the doemstic bank.

 

Nav lights depends upon exactly what you mean. If it involves a riding/anchor light then I would use the domestic bank, otherwise I would probably use the engine battery because they should only be in use when the motor is running and charging and use the ignition switch to ensure they can not be left on with the engine off.

 

However the domestic bank will also be fine for everything as well.

 

Just my thoughts. Others will have different ideas.

 

If you do not yet have a domestic bank by all means temporally connect them to the engine battery for test purposes but make sure you leave the leads/tails long enough to change it later when you get the doemstic bank.

[boater123]

Thanks, that simplifies things.

[Paul C]

There's a case to be made for ONLY the starter motor.

 

There's a case to be made for starter motor + essential electrics to run the engine, which need a separate connection (eg fuel solenoid - although these tend to be "power to close" rather than "power to open" on boats; I can't think of anything else on a diesel but there might be something, like alternator excitation??? (it could probably self-excite though)).

 

There's a case to be made for the bilge pump - or having 2 bilge pumps, one connected to each battery bank - a floating boat with all flat batteries is better than a sunken boat with a good starter battery.

 

There's no case to be made for headlamp, nav lights etc because if they were left on and flattened the battery.....

 

Horn is moot - its used so little (and you know it is working...) that it doesn't really impact. Mind you, it may be possible for it to fail in a "drawing current" configuration, for example if it got wet? So I'd say no, don't connect to engine/start battery on that basis.

[peterboat]

Is that an actual bathroom bilge pump or a shower pump. The reason I ask is because those shower pumps that use a bilge pump in a box are known for leaking and clogging. If you have a bilge under the shower to pump shower water from I fear it could lead to smells in hot weather.

 

My opinion only. The engine battery is separated from the domestics so that whatever happens to the doemstic bank you can always start the engine to recharge so you need to minimise the loads on the engine battery.

 

I wire the horn via the ignition switch so it can not be accidental blown when you are tied up with the engine off so that means fed from the engine battery.

 

The tunnel lamp could be treated in the same way but it may be pushing the switch contacts a bit. Maybe use a relay. This will prevent you leaving it on when the engine is off. I think mine works fine without a relay but time will tell.

 

Water pump and shower pump definitely form the doemstic bank.

 

Nav lights depends upon exactly what you mean. If it involves a riding/anchor light then I would use the domestic bank, otherwise I would probably use the engine battery because they should only be in use when the motor is running and charging and use the ignition switch to ensure they can not be left on with the engine off.

 

However the domestic bank will also be fine for everything as well.

 

Just my thoughts. Others will have different ideas.

 

If you do not yet have a domestic bank by all means temporally connect them to the engine battery for test purposes but make sure you leave the leads/tails long enough to change it later when you get the doemstic bank.

I am with you Tony on this having seen flat batteries due to nav laghts and tunnel lights left on

[Chalky]

I've got the Starter motor, the tunnel light and the horns wired off the starter battery, everything else is off the domestic. There is a relay connected to the engine ignition switch so I can't leave the lights on.

[Arthur Brown]

IMO optimally everything should run off the house battery bank except; the starter and any necessary fuel priming pump. Some things such as the nav lights could possibly be run from the engine via a relay so that they can't be left on when the "ignition" switch is off. The starter battery is your only effective means of starting the engine, which is the only internal method of charging batteries independently. The starter battery should be protected against inadvertent discharge.

[WotEver]

IMO optimally everything should run off the house battery bank except; the starter and any necessary fuel priming pump. Some things such as the nav lights could possibly be run from the engine via a relay so that they can't be left on when the "ignition" switch is off. The starter battery is your only effective means of starting the engine, which is the only internal method of charging batteries independently. The starter battery should be protected against inadvertent discharge.

Agreed 100%.

[HappyDayz]

IMO optimally everything should run off the house battery bank except; the starter and any necessary fuel priming pump. "Some things such as the nav lights could possibly be run from the engine via a relay so that they can't be left on when the "ignition" switch is off,,". The starter battery is your only effective means of starting the engine, which is the only internal method of charging batteries independently. The starter battery should be protected against inadvertent discharge.

I've only tamely day boated on the River Lea @ Stanstead Abbots so far, but hopefully intend to go further, summer permitting, later this year. So far i've used a single 120 AH leisure battery and a solar trickle charger'. if we do get more adventurous i had it in mind to run a second battery likely via a relay or split charger caravan style.

 

You mention nav lights, which i think are not needed unless underway, engine is running and not a power issue, but what about the 'at anchor' white lights which may be needed to be on overnight, and the bilge pump?

 

Couple of years back i had a 1st ever BSC examination, we did not bother wiring the nav lights up being intended as canal day boat only, he said at busy times we may be delayed past our planned time of return, so as the lights were inplace he insisted they actually worked - but the said i could simply remve them and he woukd issue the certificate ?.

 

 

Alan

[Sir Nibble]

I would have said anything regarding navigation like nav lights, tunnel light, horn from the engine battery through ignition but since they are only required under way it doesn't matter what battery you connect them too since they are powered by neither, they are powered by the alternator. So logically I suppose everything on domestic except engine instruments and glow/start. An anchor light shouldn't come into it as that should be an oil lamp of course!

[ditchcrawler]

 

 

Couple of years back i had a 1st ever BSC examination, we did not bother wiring the nav lights up being intended as canal day boat only, he said at busy times we may be delayed past our planned time of return, so as the lights were inplace he insisted they actually worked - but the said i could simply remve them and he woukd issue the certificate .

 

 

Alan

I don't think Nav Lights even get a mention in the Boat safety scheme so I am not sure what he was saying. I would say that et least 70% of Narrowboats with navigation lights the lights do not comply with the Col Regs. When do you expect to anchor overnight in a river?

[Iain_S]

But definitely heater plugs to engine battery.

 

In our early days with Copperkins, we arrived to a flat cabin bank. Engine battery was OK, but we couldn't start the engine without wiring alterations, as the heater plug relay switched connection was on the cabin bank. A cabin bank will jump start a flat engine battery, but an engine battery won't "jump start" a (much larger capacity) cabin bank!

 

My rule is nothing that doesn't get switched by the "ignition" switch gets connected to the engine battery.

[Chalky]

I have 2 fuse boxes, 1 for each battery. The engine battery powers the tunnel light and the horn. Both are relay switched and are isolated when the ignition's off. A 5W solar panel also connects to this fuse box via a a charge controller. The second fuse box is connected to the domestic batteries and powers everything else.

I carry a spare jump lead so I can start off the domestics if necessary - I might change this to a contactor if I decide to bridge the alternators.

 

The bilge pump is connected to both fuse boxes via a home built controller. This draws power from the domestics and will run the pump from them till they're flat. It will then draw power from the engine battery. Potentially this could leave me with no ability to start the engine but I decided keeping the boat afloat was more important. (I might modify it to pulse the horn if it switched to the engine battery as an emergency warning)

[GUMPY]

Anything directly related to the engine comes of the engine battery.

Nav lites, headlights, horn, Bilge pump all come off the domestic bank but are relay controlled by the ignition.

[boat fan]

IMO optimally everything should run off the house battery bank except; the starter and any necessary fuel priming pump. Some things such as the nav lights could possibly be run from the engine via a relay so that they can't be left on when the "ignition" switch is off. The starter battery is your only effective means of starting the engine, which is the only internal method of charging batteries independently. The starter battery should be protected against inadvertent discharge.

 

 

That is usually conventional practice.

[Tony Brooks]

 

 

That is usually conventional practice.

 

Maybe by those who take things at face value as so many do. The statement about the engine battery being the ONLY means of starting falls into the same category. Read a few posts back and see that one can always jump start from the domestic bank in most cases.

 

As far a i know there is no official standard on this hence the original question.

[alan_fincher]

Couple of years back i had a 1st ever BSC examination, we did not bother wiring the nav lights up being intended as canal day boat only, he said at busy times we may be delayed past our planned time of return, so as the lights were inplace he insisted they actually worked - but the said i could simply remve them and he woukd issue the certificate.

 

Goodness knows where that came from, but I would seriously question the competance of the inspector used.

 

There is absolutely nothing like this contained in the BSS requirements.

[Tam & Di]

I am currently fitting out a sail away widebeam and have begun my first fit of electrics.

 

To my mind it depends on how seriously you expect to be cruising and to what extent you would be on rivers. Ideally you would have the capability of joining the batteries in parallel if necessary, or starting the engine from the domestic bank by a simple switch rather than having to find your jump leads and using those. On rivers you should certainly have the capability of running nav lights and any other navigational equipment (including pumps) from either bank so they always have a back-up power if it becomes necessary. All very OTT if you'll only be on canals though.

Edited July 10, 2016 by Tam & Di

[boat fan]

 

Tony Brooks, on 10 Jul 2016 - 5:01 PM, said:

 

Maybe by those who take things at face value as so many do. The statement about the engine battery being the ONLY means of starting falls into the same category. Read a few posts back and see that one can always jump start from the domestic bank in most cases.

 

As far a i know there is no official standard on this hence the original question.

 

Maybe this will make things a little clearer ?

Xantrex series regulator.

https://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=&url=http%3A%2F%2Fwww.xantrex.com%2Fpower-products%2Fpower-accessories%2Falternator-regulator.aspx&psig=AFQjCNEFgzdkC1we9upPXcYvKIWJUO2TzA&ust=1468232640953571

Edited July 10, 2016 by boat fan

[ditchcrawler]

I have 12 volt engine batteries and 24 volt house batteries, not everything is black and white.

[boat fan]

I have 12 volt engine batteries and 24 volt house batteries, not everything is black and white.

 

 

No , indeed it is not.

 

The original question may seem simple , but is very user specific.

 

And , of course , lot of assumptions.......

 

Good luck all.

Edited July 10, 2016 by boat fan

[Tony Brooks]

 

 

Maybe this will make things a little clearer ?

 

And how does that add anything to the OPs question - that is unless your are pushing Xantrex products?

 

As far as I can see its just a split charging device, the OP may have twin alternators or a different charge splitter. I would also question that diagram. I think those of us with training and experience may conclude the alternator is connected to the wrong battery bank but doing it the way allows the marketeers to make largely spurious clams about it charging the engine batteries before the domestics.

 

I could go into the details to explain it but to do so would take this way off topic and do nothing to help the OP.

Edited July 10, 2016 by Tony Brooks

[boat fan]

Nice try , have a good day.

[Tony Brooks]

I do not understand what you are trying to say. rather Late in the thread you wrote something that in my view needed challenging. You respond with what looked like an unrelated random wiring diagram you found. I pointed out it did not relay to the original question and that myself and probably others consider less than ideal. What was that tying to do other than keep things clear for the OP.

 

What are you trying to say?