Electrics. Where to start.

[truckcab79]

Starting to plan our new (to us) boat. A 36ft Springer that needs a new interior.  I’ll 

also replace all the electrics while it’s stripped. 
 

‘ALL’ the electrics won’t be much.  I figure that I’m starting from the following assumptions which might all be wrong. 
 

All lighting on 12v

 

Water pump for bilge 

 

water pump for sink and shower 

 

Radio. 12v or maybe just a rechargeable. 

TV. Probably won’t bother but 12v if we do. 

240v sockets.  Daft not to have a couple so let’s say two doubles.  Rarely anything plugged in. Tool chargers maybe, phones, iPad. 

 

Fridge on 12v presumably. B

Navigation lights. 
 

Couple of 12v and USB sockets maybe.  
 

Solar.  
 

 

So…. Where do I start. Out of interest while browsing Bimble I saw this.

 

https://www.bimblesolar.com/offgrid/complete-packages/250-500w-kits/300W-complete

 

 Would be good to know why this is / isn’t suitable for my needs as it’s seems very well priced for what looks like a fairly complete kit of parts.

 

Any advice or guide welcome.  See loads on YouTube but they seem a bit light on the detail I need.   
 

 

 

And where’s a good site for electrical equipment.  Car hobbies I’ve always used Vehicle Wiring Products  or TLC Direct for home but I’d imagine much of that is inappropriate for boat use.  

[Tracy D'arth]

Forget the nav lights, not required where you will be going with a 36' Springer.

[Morris]

3 minutes ago, Tracy D'arth said:

Forget the nav lights, not required where you will be going with a 36' Springer.

 

Are they not required on some navigations such as the Aire and Calder, or is that only if moving in low light conditions?

[PaulD]

Everybody will want to know if it is weekend boat or live aboard. If live aboard how will you charge the battery in winter ?

 

300w inverter and one battery is a bit basic.

 

Have you studied the BSS requirements ?

 

I fitted my electrics but it took many weeks. Went to vehicle wiring products for a lot of stuff - they are very good.

 

Good luck. 

[Jen-in-Wellies]

26 minutes ago, truckcab79 said:

All lighting on 12v Yes

 

Water pump for bilge Bilge pump for bilge. Oil and general yuck in the bilge will mess a typical boat potable water pump up. They also don't like being run dry.

 

water pump for sink and shower Yes

 

Radio. 12v or maybe just a rechargeable. Yes. These days, I have either a small FM radio with four rechargable AA's, or just stream the radio station over the interwebs to an ipad.

TV. Probably won’t bother but 12v if we do. Don't bother. Stream to a gadget.

240v sockets.  Daft not to have a couple so let’s say two doubles.  Rarely anything plugged in. Tool chargers maybe, phones, iPad. See if you can do without. Phones and ipads can be charged from 12V, or USB socket. Tool chargers maybe the only thing, but could be done from a very small inverter.

 

Fridge on 12v presumably. B Install close to the batteries if at all possible. Will be your biggest electric consumer by far. Voltage drop is the enemy of these, so large and expensive cross section cables needed for longer distances.

Navigation lights. Only if you are regularly cruising where they are needed. Tunnel light can be of its own batteries if you don't want to run wires to it.
 

Couple of 12v and USB sockets maybe.  Yes. Watch out for standby current drawn by the voltage converter in a 12V to USB socket.
 

Solar.  

 

[truckcab79]

7 minutes ago, PaulD said:

Everybody will want to know if it is weekend boat or live aboard. If live aboard how will you charge the battery in winter ?

 

300w inverter and one battery is a bit basic.

 

Have you studied the BSS requirements ?

 

I fitted my electrics but it took many weeks. Went to vehicle wiring products for a lot of stuff - they are very good.

 

Good luck. 

Cheers. No. Haven’t studied anything yet. Just going to bore you all rigid with questions but I will.  
 

It’s not a liveaboard.   Weekends and occasional holidays.  And we’re very low maintenance.  I want as little as possible on it really but as we’ll  be stripping it out it makes sense to run any cabling that I MIGHT want at the same time.  
 

As far as the inverter is concerned if 300 is too little what should I be looking at and is it a case of ‘that bundle is great value but swap the 300 for a 500 and buy two batteries and you’re good to go’.  
 

Sorry. All new to me this.   Trying to keep sort of to a budget by only buying what I need.  Don’t want to spend £5k on the electrics and then find I’ve bought a bundle that wouldn’t look out of place running an aircraft carrier and I only ever use capacity that I could have bought for a grand.  

9 minutes ago, Jen-in-Wellies said:

 

Thanks for this.  
 

 

And really daft question.  The 300 inverter says it has sockets. Does that mean it will power sockets or you use ones that are built into it. And if the latter, can you also do the former.   

Edited September 6, 2023 by truckcab79

[LadyG]

A 12v compressor fridge is pretty expensive, I have one, but I'd also consider a smaller top loader type fridge, no freezer, maybe on sliding shelf.  Big enough to chill a crate of beer.

A 240v fridge needs carefull matching with the inverter. Don't box them in tight, set up a draught, maybe from bilge.

Will you have an inverter charger?

Edited September 6, 2023 by LadyG

[Tony Brooks]

26 minutes ago, truckcab79 said:

As far as the inverter is concerned if 300 is too little what should I be looking at and is it a case of ‘that bundle is great value but swap the 300 for a 500 and buy two batteries and you’re good to go’.  

 

I think the fear was more to do with the size of the battery, rather than the inverter. Before you go too far, you need to list all your equipment and then do a power audit. That will give you an idea about how much battery capacity you need (double the power audit figure) and then most importantly of all work out how you are going to recharge the battery to all but 100% at least once a week. Be aware that the engine alternator will only provide an average f about 50% of its rated capacity over three to four hours, and after that the average drops until maybe 8 to 10 hours later you are only charging at a very few amps.

 

Far too many new boaters ignore the charging requirements and end up buying a lot of batteries before they learn. Read the Battery Primer pinned near the top in the Maintenance section.

[roland elsdon]

Loose the 240 .

We have no mains ring in 13 years

We have a small inverter that plugs into a 12 v socket. Thats it, if the cordless drill needs a charge we blow the dust off the inverter.

we have 6  usb sockets phones/ pad garmin devices.

 

[Bod]

Read and understand this part of the Smartgauge website.

http://www.smartgauge.co.uk/cable_type.html

It is regarding selecting the correct size wire to avoid Voltage-drop.

In the lenght of individual cables in your short boat the drop may not be too great, but will need to be accounted for.

The length of the boat may be 36 feet, but some cable runs out and back to the battery, could be in the region of 90 feet, all the up's and downs, turns to left and right all add lenght.

Volt-drop is basically the internal resistance to the volts passing through.

A cable carrying 240 volts loosing 5 volts over it's distance, is not a problem.

The same cable carrying 12 volts, loosing 5 volts is a major problem.  The cable needs up sizing to reduce the lose to 0.05 of a volt.

To size for volt-drop normally means the cable is well over specc'd for current capacity.

The author of the above web-site is an acknowledged expert in this field.

 

Bod.

[truckcab79]

6 minutes ago, Tony Brooks said:

 

I think the fear was more to do with the size of the battery, rather than the inverter. Before you go too far, you need to list all your equipment and then do a power audit. That will give you an idea about how much battery capacity you need (double the power audit figure) and then most importantly of all work out how you are going to recharge the battery to all but 100% at least once a week. Be aware that the engine alternator will only provide an average f about 50% of its rated capacity over three to four hours, and after that the average drops until maybe 8 to 10 hours later you are only charging at a very few amps.

 

Far too many new boaters ignore the charging requirements and end up buying a lot of batteries before they learn. Read the Battery Primer pinned near the top in the Maintenance section.

Cheers. Have already started logging my power audit info but just using estimated numbers for now as I haven’t actually bought anything as yet.  
 

We’ll be on a leisure mooring so no power.  Charging I’m assuming will be predominantly by solar.  I’ll have a suitcase generator for backup.  At least I’m buying one for the refit and will use it after if I need to.   

5 minutes ago, Bod said:

Read and understand this part of the Smartgauge website.

http://www.smartgauge.co.uk/cable_type.html

It is regarding selecting the correct size wire to avoid Voltage-drop.

In the lenght of individual cables in your short boat the drop may not be too great, but will need to be accounted for.

The length of the boat may be 36 feet, but some cable runs out and back to the battery, could be in the region of 90 feet, all the up's and downs, turns to left and right all add lenght.

Volt-drop is basically the internal resistance to the volts passing through.

A cable carrying 240 volts loosing 5 volts over it's distance, is not a problem.

The same cable carrying 12 volts, loosing 5 volts is a major problem.  The cable needs up sizing to reduce the lose to 0.05 of a volt.

To size for volt-drop normally means the cable is well over specc'd for current capacity.

The author of the above web-site is an acknowledged expert in this field.

 

Bod.

Cheers for the link. 👍

9 minutes ago, roland elsdon said:

Loose the 240 .

We have no mains ring in 13 years

We have a small inverter that plugs into a 12 v socket. Thats it, if the cordless drill needs a charge we blow the dust off the inverter.

we have 6  usb sockets phones/ pad garmin devices.

 

Cheers.  I know I can definitely live without one. Just seems to make sense to put it in on day 1 just in case.  

58 minutes ago, Jen-in-Wellies said:

 

Yea.  Sorry. Didn’t really mean water pump in the same manner as clean water pump.  Bilge pump obviously.  

Have read that smart gauge info. Very useful and nice simple maths.  Bookmarked.  👍

 

Likewise BSS. Have skimmed. Mostly  common sense stuff and in the main very easy to comply with if you know before it’s too late.  
 

 

[MtB]

28 minutes ago, truckcab79 said:

Cheers.  I know I can definitely live without one. Just seems to make sense to put it in on day 1 just in case.

 

I'm inclined to disagree. Once you add 230Vac you enter in a whole new world of requirements. I just plug a 300W inverter into a cigar socket if I need mains, which is not very often. 

[Tony Brooks]

8 minutes ago, MtB said:

 

I'm inclined to disagree. Once you add 230Vac you enter in a whole new world of requirements. I just plug a 300W inverter into a cigar socket if I need mains, which is not very often. 

 

Me too, and on a boat in summer or winter the temperature can be such that battery powered equipment refuses to charge because it is either too hot or too cold.

 

To the OP, the electrical notes on my website may help as well. http://www.tb-training.co.uk

Edited September 6, 2023 by Tony Brooks

[truckcab79]

Thank you both.  
 

Is there a resource for suggested wiring layouts / circuits for a narrowboat?   As said, watched loads on YouTube but it’s not very instructional or maybe I haven’t found the right ones yet.  

[Alan de Enfield]

24 minutes ago, MtB said:

I just plug a 300W inverter into a cigar socket if I need mains, which is not very often. 

 

I tried that only once.

 

300w inverter will draw approx 30 amps, with a cigarette lighter socket only being rated at 10 amps I ended up with a load of molten plastic and nasty fumes.

 

There is a reason why they have 10 amp fuses !

[Tony Brooks]

10 minutes ago, truckcab79 said:

Thank you both.  
 

Is there a resource for suggested wiring layouts / circuits for a narrowboat?   As said, watched loads on YouTube but it’s not very instructional or maybe I haven’t found the right ones yet.  

 

See my last post, but it is very generic, and  you would have to use the info to make your own diagram.

[truckcab79]

18 minutes ago, Alan de Enfield said:

 

I tried that only once.

 

300w inverter will draw approx 30 amps, with a cigarette lighter socket only being rated at 10 amps I ended up with a load of molten plastic and nasty fumes.

 

There is a reason why they have 10 amp fuses !

Good point and surely for convenience a small 300w inverter with say one socket permanently wired would be better and neater?   

[Alan de Enfield]

3 minutes ago, truckcab79 said:

Good point and surely for convenience a small 300w inverter with say one socket permanently wired would be better and neater?   

 

And yes a 'proper' 12v plug & socket if not making it a permanent job.

[Jen-in-Wellies]

29 minutes ago, truckcab79 said:

Is there a resource for suggested wiring layouts / circuits for a narrowboat?

 

Battery +ve terminals > Big wire to Big Fuse > Master Switch > +ve Bus Bar.

-ve Bus Bar > big wire > Battery -ve terminals.

Then for each individual circuit:

+ve bus bar > Smaller fuse to suit smaller wire > switch > Gadget +ve > Gadget -ve > -ve Bus Bar

Repeat for each circuit. Lights, pumps, fridge etc.

Some circuits can bypass the big fuse and battery master switch and be wired directly to the battery, provided they are each protected by a fuse suited to the wire size, close to the battery positive.

[truckcab79]

15 minutes ago, Jen-in-Wellies said:

 

Battery +ve terminals > Big wire to Big Fuse > Master Switch > +ve Bus Bar.

-ve Bus Bar > big wire > Battery -ve terminals.

Then for each individual circuit:

+ve bus bar > Smaller fuse to suit smaller wire > switch > Gadget +ve > Gadget -ve > -ve Bus Bar

Repeat for each circuit. Lights, pumps, fridge etc.

Some circuits can bypass the big fuse and battery master switch and be wired directly to the battery, provided they are each protected by a fuse suited to the wire size, close to the battery positive.

Cheers.  Nice and simple. That’s what I like.   I’m quite happy I think with the 12v circuits. It’s only a small boat so for things like lighting I’ll probably go with individually switched units so I’m not worrying about having to accommodate separate light switches or anything that I don’t really need to keep it all nice and simple.  
 

In everyone’s experience are the 6 circuit distribution boards plenty or would you advise starting with 12.  Spares would be handy of course but from a space point of view if 6 is sufficient then I’ll limit myself to that when laying out circuits.  And if 12 then any advantage or disadvantage to 2 x 6 rather than 1 x12.  Other than cost.  12’s seem to be disproportionately more expensive to 6’s for some reason.  

[jonathanA]

you may already know this but cant see it mentioned so will put it here. unlike a car the boat hull/steelwork must NOT be used as the earth return or one leg of the electric supply to any device on the boat.  you must run a +ve and -ve (usually red & black) wire to each and every device.   

 

so for instance a horn at the front of the boat needs a +ve and -ve wire running to it, you cant just take one wire to the bolt holding the horn on to the boat. 

 

A useful book is the narrow boat builders guide by Graham Booth. 

 

[truckcab79]

I did know this but only because someone pointed it out to me on the forum.  Never knew before.  👍

 

Another one for you and I know the proper answer is probably ‘finish doing your power audit’, but in your collective experience for a 36ft leisure boat what capacity typically would I be looking for in terms of:

 

Batteries.  Quantity and capacity.
Solar

Inverter

 

 

 

Edited September 6, 2023 by truckcab79

[Jen-in-Wellies]

12 minutes ago, truckcab79 said:

In everyone’s experience are the 6 circuit distribution boards plenty or would you advise starting with 12.  Spares would be handy of course but from a space point of view if 6 is sufficient then I’ll limit myself to that when laying out circuits.  And if 12 then any advantage or disadvantage to 2 x 6 rather than 1 x12.  Other than cost.  12’s seem to be disproportionately more expensive to 6’s for some reason.  

I have used these distribution boards in the past, which I presume are the ones you are talking about, but wouldn't now. Now I would just use blade fuses, with them in a suitable holder, however many is needed for the number of circuits make sense. If the electrical system is made properly, a breaker tripping should be an almost unheard of event, so a fuse will be fine. I've not had a 12V breaker trip since wiring my boat. No idea if they actually would in a crisis.

 

[Alan de Enfield]

23 minutes ago, truckcab79 said:

I did know this but only because someone pointed it out to me on the forum.  Never knew before.  👍

 

Another one for you and I know the proper answer is probably ‘finish doing your power audit’, but in your collective experience for a 36ft leisure boat what capacity typically would I be looking for in terms of:

 

Batteries.  Quantity and capacity.
Solar

Inverter

 

 

 

 

 

Every one will come up with differing figures 

 

We are a long term leisure user (3 or 4 months at a time) and have :

 

6x 230Ah batteries.

1 x 170w Low-light solar panel.

1x 1800w Inverter.

 

12v Fridge

230v Freezer

Microwave

Twin Tub washing machine

Air Fryer

Gas Hob

Gas Oven

[truckcab79]

11 minutes ago, Jen-in-Wellies said:

I have used these distribution boards in the past, which I presume are the ones you are talking about, but wouldn't now. Now I would just use blade fuses, with them in a suitable holder, however many is needed for the number of circuits make sense. If the electrical system is made properly, a breaker tripping should be an almost unheard of event, so a fuse will be fine. I've not had a 12V breaker trip since wiring my boat. No idea if they actually would in a crisis.

 

Yep. Same principle. 6’s seem to be about £30-35 and 12’s literally 5 times the price but space is more my consideration than money.
 

I know I can label a fuse box but quite like the neatness of these I suppose as much as anything.    
 

1 minute ago, Alan de Enfield said:

 

 

Every one will come up with differing figures 

 

We are a long term leisure user (3 or 4 months at a time) and have :

 

6x 230Ah batteries.

1 x 170w Low-light solar panel.

1x 1800w Inverter.

 

12v Fridge

230v Freezer

Microwave

Twin Tub washing machine

Air Fryer

Gas Hob

Gas Oven

Wow.  Way more than I expected.  Must be a palace!   Having said that I have no intention of having a washing machine, freezer or microwave.  I’ve never even had a microwave at home let alone on the boat. 😂

 

Love my air-fryer but also won’t be having one on the boat.  
 

Apart from a small fridge (12v) and an oven (lpg)  I can’t actually think of any ‘appliance’ I need  on board.