24 volt windlass on 12 volt boat? Anyone done this?

[pvb]

Unless my toilet was fused near source and then an other cable run to the main panel then to the battery so sorry your talking rubbish your using extreme examples to prove a useless point, on a 13 metre boat how is it possible to have a toilet 12 metres from a power source,

Quite easily, boat wiring usually doesn't go in straight lines.

the toilet is run to a separate fused panel 3 feet away 30 AMP CABLE and then from the fuse panel back to the main fused master (30 AMP CABLE) panel were it is feed from 300 amp core wire from the master battery , as the run is more than 6 feet from first fuse to master panel it is fused again to protect the run , all large runs need 2 fuses to protect either end

More misconceptions, you don't need fuses at each end, only at the battery end. Additional fuses serve no purpose and are a source of potential failure.

9 feet =2,74 metres on a 24 volt system like I said earlier you don't need to deal in fractions , so the voltage drop in negligible so please use facts not rumbles from your belly and pie in the sky thoughts

No, the voltage drop isn't negligible. Jabsco, for example, would recommend at least 4mm² cable for that run. I'm only a simple engineer, so I'm used to dealing in facts.

 

[pvb]

It's noticeable that a lot of production boats seem to have 'bow batteries' these days.
Usually 12V, the same as everything else on the boat.
Why do you think that is?
I wonder if the likes of Bavaria have actually done the design properly and have good logic behind their solution?

I think that in the case of Bavaria, they tend to use a standard pre-made wiring loom for each model of boat, and then if a buyer specifies a thruster they stick a 12v battery in the bow, with the cable already there to charge it. The alternative would be to have a custom-made loom for each individual boat.

 

[moomba]

Quite easily, boat wiring usually doesn't go in straight lines.



More misconceptions, you don't need fuses at each end, only at the battery end. Additional fuses serve no purpose and are a source of potential failure.



No, the voltage drop isn't negligible. Jabsco, for example, would recommend at least 4mm² cable for that run. I'm only a simple engineer, so I'm used to dealing in facts.

1. you use the least run as possible my boat is pretty straight
2,if you don't use fuses at each end then why do most electronics i.e vhf radio and my electric toilet have a fuse at the end and I fuse it at the beginning , you also need to protect long runs of cable yes the fuse at beginning will halt the current but if that fails what is protecting your cable as well as the appliances you are running nothing , so how can you say that this is wrong , this is called another level of safety . I know what I would like !!
3, if you work it out using the correct formula you will find the that drop in voltage is way less than the required 3% that is required in a DC system as DC is prone to larger voltage drop that AC current due to its low voltage therefore you should be looking at 3% or less on my calculation I get that V = IR I =V/R Ohms Law

VOLTS =24
AMPS = 15
CABLE SIZE 4MM
LENGHT OF CABLE 3 M

DROP IN VOLTS = 0.39

If your a good engineer you would know that 30 amp cable is around the 4mm mark I think 32amps is the right one you would also know OHMS LAW AND WORKED IT OUT and you would always fuse your electronics

please don,t put stuff up unless you either know your stuff or research it

You also mention Jabesco did you research their 24 volt toilet or 12 volt as I read it it say 8 amp max current for 24 volts the ones I have this is due to halfing the amps needed in a 24 volt system , why larger boats use 24 volts to reduce cable sizing
engineer yes electrician I don't think so

 

[pvb]

I wouldn’t hold your breath. The standard wiring for the shore power on the Bavaria 32’s & 34’s I’ve had the misfortune to work on is to charge the domestics only. Engine start battery was only charged when you were under engine.

I think you'll find they're a bit better in recent times. My Bavaria has a shore power charger with separate feeds to the start, domestic and thruster batteries.

 

[Lon nan Gruagach]

2,if you don't use fuses at each end then why do most electronics i.e vhf radio and my electric toilet have a fuse at the end and I fuse it at the beginning

Either a rhetorical question or and indication of not quite knowing how circuits are designed.
To answer, though....
The fuse at the start (power source end) of the cable is to disconnect the power if there is a situation that would make the cable dangerously hot.
The fuse at the end (equipment end) is almost always considered as part of the equipment and is intended disconnect the equipment if it draws more than the expected current, an indication that it has become faulty.

Note: The equipment manufacturers have absolutely no idea of the rating of the cable that provides its supply, and as such cannot and do not provide any protection for that cable.

 

[lw395]

I wouldn’t hold your breath. The standard wiring for the shore power on the Bavaria 32’s & 34’s I’ve had the misfortune to work on is to charge the domestics only. Engine start battery was only charged when you were under engine.

My car only charges its engine battery when the motor's running, so far so good.

 

[moomba]

Either a rhetorical question or and indication of not quite knowing how circuits are designed.
To answer, though....
The fuse at the start (power source end) of the cable is to disconnect the power if there is a situation that would make the cable dangerously hot.
The fuse at the end (equipment end) is almost always considered as part of the equipment and is intended disconnect the equipment if it draws more than the expected current, an indication that it has become faulty.

Note: The equipment manufacturers have absolutely no idea of the rating of the cable that provides its supply, and as such cannot and do not provide any protection for that cable.

OH please people think out of the box if you are using a breaker and then run a long length of wire to a specific piece of equipment then why would you not fuse that equipment(toilet, radar ,mfd, usb ports) , it does not always have to rate to the equipment but at least protect the long wire it is up to you , I cant believe we all think breakers or fuses at the beginning of a circuit are infallible and will always protect you , would you rather be in a car with 6 air bags or 1 this is a choice it is not required but I urge anyone rewiring or putting in new equipment think about your fuse set up it may save your boat. I don't do this to be right just to be safe , I have rewired a 42 ft boat this way pumps, lighting, equipment, etc the whole boat 10 new batteries 3 banks 2 electrical toilets all new nav lights usb ports in 4 cabins 8 fans etc etc , all fused each on its own circuit, overkill yes but I know its right , so another silly answer to me not understanding circuits if if was wrong it would not work !! as always 2 safety nets are better than one ,

 

[lw395]

It might be down to price of cable , production boats try to minimise costs through the boat so you will find their wires are right on the button in regards to no don't say it ,SORRY voltage drop

Yes, the cable to do a proper job of wiring a windlass can be pricey.
IMHO, it's a good idea to look at one particular boat/windlass requirement and do the sums. Generalisation is of limited value.
I don't have a personal dog in this contretemps, we have a mostly nylon anchor string and pull it up manually by hand. We favour the builders' gloves from Toolsation but others wil do the job, subject to proper engineering analysis.

If you do the full analysis, with a bow battery, there is a blance between sharing the load between bow/house/alternator, which suggests fat cables, and making the bow battery do the work, which implies thinner cable.
In between can be dangerous, if the bow battery is sick, the cabling can be overloaded.
When you get into the kW arena, 12V is basically a crap idea. But you are where you are, and 24V is not actually all that much better.

 

[bigwow]

only if you have a VW TYPE 2 camper or a ford escort mk 1 or 11

Or a U Boat
https://wordery.com/u-boat-manual-a...NQIzykLglNaIJNuJLROI4TjYMUkioc2QaAi2REALw_wcB

 

[pvb]

2,if you don't use fuses at each end then why do most electronics i.e vhf radio and my electric toilet have a fuse at the end and I fuse it at the beginning , you also need to protect long runs of cable yes the fuse at beginning will halt the current but if that fails what is protecting your cable as well as the appliances you are running nothing , so how can you say that this is wrong , this is called another level of safety . I know what I would like !!

Jabsco don't suggest putting a fuse at the toilet end of the cable.

3, if you work it out using the correct formula you will find the that drop in voltage is way less than the required 3% that is required in a DC system as DC is prone to larger voltage drop that AC current due to its low voltage therefore you should be looking at 3% or less on my calculation I get that V = IR I =V/R Ohms Law

VOLTS =24
AMPS = 15
CABLE SIZE 4MM
LENGHT OF CABLE 3 M

DROP IN VOLTS = 0.39

For 6 metres of 4mm² cable, the voltage drop would be closer to 0.45v.

If your a good engineer you would know that 30 amp cable is around the 4mm mark I

What you call "tin cored" cable is actually tinned copper cable, and when it has a nominal 30A current rating it's generally 2.5mm². A previous post mentioned the supplier 12 Volt Planet, so look at this link for starters - https://www.12voltplanet.co.uk/single-core-tinned-thin-wall-cable-2-5mm-29a.html

You also mention Jabesco did you research their 24 volt toilet or 12 volt as I read it it say 8 amp max current for 24 volts the ones I have this is due to halfing the amps needed in a 24 volt system , why larger boats use 24 volts to reduce cable sizing
engineer yes electrician I don't think so

Your installation is on the borderline between Jabsco's recommendations of 4mm² or 6mm², not the 2.5mm² you've used. You can see their electrical recommendations in their manuals, eg at www.xylemflowcontrol.com/files/58XX0_DF14&17_Toilet_Datasheet.pdf

please don,t put stuff up unless you either know your stuff or research it

People who've been here a bit longer than a fortnight know only too well that I do both.

 

[Lon nan Gruagach]

Or a U Boat
https://wordery.com/u-boat-manual-a...NQIzykLglNaIJNuJLROI4TjYMUkioc2QaAi2REALw_wcB

Mebby even a starship:

https://haynes.com/en-gb/microsites/enterprise/

 

[Lon nan Gruagach]

Note also that it is considered bad practice to have 2 breakers/fuses/protection devices of the same rating on one circuit. The ambiguity caused by not being able to easily determine the cause of the fault is significant.

 

[PaulRainbow]

Another PBO electrical thread full of utter nonsense lol

 

[moomba]

Jabsco don't suggest putting a fuse at the toilet end of the cable.



For 6 metres of 4mm² cable, the voltage drop would be closer to 0.45v.



What you call "tin cored" cable is actually tinned copper cable, and when it has a nominal 30A current rating it's generally 2.5mm². A previous post mentioned the supplier 12 Volt Planet, so look at this link for starters - https://www.12voltplanet.co.uk/single-core-tinned-thin-wall-cable-2-5mm-29a.html



Your installation is on the borderline between Jabsco's recommendations of 4mm² or 6mm², not the 2.5mm² you've used. You can see their electrical recommendations in their manuals, eg at www.xylemflowcontrol.com/files/58XX0_DF14&17_Toilet_Datasheet.pdf



People who've been here a bit longer than a fortnight know only too well that I do both.

Oh dear it is the wrong toilet never mind https://www.jabscoshop.com/marine/m...oilets/37010-4094-toilet-24v-regular-bowl.htm

8 amps max at source so 30 amp wire is more than enough (no were does it say not to fuse twice it does not say to do it but also not to do it again this is choice it will not affect your systems in way)
tinned core copper sorry for my dyslexia
you would have a short wire run to a fuse box with a fuse to protect the toilet macerator and the cable run back to the fuse panel this is instead of using long runs back to master control you can use the extra fuse box as a slave for extra lighting fans etc that you then dont need lots of wire to run back that is why we use one main wire for just one main feed back, this extra fuse is for protection as previous posted ' it is for extra security if you do not want it don't do it I want it as it adds a second degree of safety it is what you call redundancy in the system, 3 fuses one at each junction of the circuit 1 fuse at main battery bank, one fuse at distribution panel one fuse at small fuse box . that is also why we use Busbars to minimise wire keep it simply
0,45 v sorry I was 0,06 volt drop out but my answer was still the same less than 3%
30 amp wire is indeed in the american symptom 2.6mm so my apologies for that
Again I was not born a fortnight ago so what is your point here are you being a Superior snob person who likes to nip pick or can we stick to the main point that 3% voltage drop is what your looking for in a DC system please
In the name of the wee Man
key points
3% voltage drop in a DC system is what your aiming for less the better
voltage does not drop or gain exponentially it is a constant
make sure the right cable is used for the right job
fuse every time you take a junction i.e battery to main panel to slave fuse box
24 volt systems are half the amperage so a 20 amp toilet on a 12 volt will only need 10 amps on 24 volts so wire decreases but runs can get longer this is why on a larger boat and on MY BOAT we use slave fuse boxes and bus bars to minimise large bundles of cable runs
remember anyone can call them self an marine electrician , there is no coding or certificate they need to show you, and you can re wire your own boat , but only a qualified electrician can do your home , who do you trust. and why is having an extra fuse every bad a fuse is a protection of the circuit it never ever EVER stops that circuit working , I rather a 30 pence fuse blow that a very expensive toilet, mfd OR A BLOODY 150 POUNDS CAFERO FAN utter madness.

 

[moomba]

Note also that it is considered bad practice to have 2 breakers/fuses/protection devices of the same rating on one circuit. The ambiguity caused by not being able to easily determine the cause of the fault is significant.

no just look for the blown fuse rather simple really

 

[pvb]

Oh dear it is the wrong toilet never mind https://www.jabscoshop.com/marine/m...oilets/37010-4094-toilet-24v-regular-bowl.htm

Doesn't matter, I said it was an example of Jabsco's wiring instructions. Yours may be a cheaper model, but it'll have essentially the same current requirements. If your toilet is 3 metres away from the power source, it's right on the limit of Jabsco's 4mm² recommendation, but you're happy to use cable almost half as thick.

you would have a short wire run to a fuse box with a fuse to protect the toilet macerator and the cable run back to the fuse panel this is instead of using long runs back to master control you can use the extra fuse box as a slave for extra lighting fans etc that you then dont need lots of wire to run back

So not only do you undersize the cable for the toilet, you also load it with more current for other equipment! I don't think there's much point continuing to reason with you.

 

[PaulRainbow]

So not only do you undersize the cable for the toilet, you also load it with more current for other equipment! I don't think there's much point continuing to reason with you.

See post #53

 

[PaulRainbow]

no just look for the blown fuse rather simple really

You have obviously had a bit of a read up on wiring, but havn't grasped some of the basics, such as cable sizing, where you seem to have forgotten that you have to count the length of the negative cable too.

It's also perfectly valid to fit satellite fuse panels or bus bars, but not if you're wiring them with undersized cabling and inadequate fuses. You can run a cable from the isolator or a busbar to a secondary fuse panel/switch panel/ busbar, but the cable has to be rated for the total load, at the very least (better to go over to allow for some voltage drop and future expansion). You then have to protect that cable/fuse box etc, no need to worry about the individual circuits after the fuse panel at this point, so fit a fuse rated for the cable.

At the fuse board you fuse each circuit accordingly, minimum of the rated load, maximum of the cable rating. You do not fuse both ends. Only time you fuse both ends is if there is a power source at the other end. In the case of your toilet, you fuse for the motor rating, plus a little. The wiring should be rated more than the motor load, but the fuse has to be rated to protect the motor from things like a jammed macerator. If you were fitting something like a VHF that comes with an inline fuse, don't be fooled into thinking you have to leave that in place and fuse the supply end of the cable too, you absolutely do not. You remove the inline fuse and fit an appropriate fuse in the fuse panel.

 

[mikefleetwood]

Well, I enjoyed reading all that

 

[Kukri]

I think I will buy a copy of the Haynes manual for the Enterprise.