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

[moomba]

A powerful windlass will draw a large amount of amps especially if under load or stuck, I would suggest bigger wire to compensate for that draw , also you would need a minimal 100 to 200 amp fuse at start of battery to minimise cooking the wire ,if not doing this your all mad , there fore your wire needs to be larger for the fuse to protect the circuit , when charging from 12 volts to 24 volts you do not need a powerful convertor as your not charging your battery bank at anything near the amps you need for the windlass to run , add to that any length of cable will suffer voltage drop so again you need to size the wire correctly, I read i think 3 copies back in a sailing magazine in regards to a windlass fire , poor cable management and not fused resulted in fire at main battery bank in boat they nearly lost everything , and asked why there circuit breaker did not work because there wire was not big enough for the current and the braker sized to large 99%, of all boat fires are electrical me I always er on the side of caution and size larger wire (no voltage drop) and fuse everywhere , my boat is 13 metres and 24 volts with a drop draw of 12 volts on separate panel with windlass of the main house with separate fuse and main bank fused at source

 

[john_morris_uk]

A powerful windlass will draw a large amount of amps especially if under load or stuck, I would suggest bigger wire to compensate for that draw , also you would need a minimal 100 to 200 amp fuse at start of battery to minimise cooking the wire ,if not doing this your all mad , there fore your wire needs to be larger for the fuse to protect the circuit , when charging from 12 volts to 24 volts you do not need a powerful convertor as your not charging your battery bank at anything near the amps you need for the windlass to run , add to that any length of cable will suffer voltage drop so again you need to size the wire correctly, I read i think 3 copies back in a sailing magazine in regards to a windlass fire , poor cable management and not fused resulted in fire at main battery bank in boat they nearly lost everything , and asked why there circuit breaker did not work because there wire was not big enough for the current and the braker sized to large 99%, of all boat fires are electrical me I always er on the side of caution and size larger wire (no voltage drop) and fuse everywhere , my boat is 13 metres and 24 volts with a drop draw of 12 volts on separate panel with windlass of the main house with separate fuse and main bank fused at source

Nothing to argue with over that except there’s no such thing as o voltage drop! I have a 100 amp breaker at the battery end of the cable run. It does trip out if the anchor snags and I press the windlass a bit... so I know it works.

The problem is that the OP asked about fitting a 24 v windlass to a 12v boat. Easy enough if your boat is already all 24 volt but I think that the conclusion for the OP is ‘don’t try and do it..’

 

[moomba]

there is no such thing as o voltage drop!

In reality the voltage does not drop immediately to zero; however, in the ideal case the resistance of the wires is ignored therefore a higher wire will result in near zero Resistance , or in laymen s terms nothing to worry about here mate.

 

[john_morris_uk]

there is no such thing as o voltage drop!

In reality the voltage does not drop immediately to zero; however, in the ideal case the resistance of the wires is ignored therefore a higher wire will result in near zero Resistance , or in laymen s terms nothing to worry about here mate.

I regret that in the high current demands of windlass motors, you can’t ignore the resistance of the wiring.

No idea what you mean by ‘not immediately dropping to zero’ in the context.

 

[moomba]

I am not going to argue this one any more but it is the law of physics and current running through a wire, if the wire is larger than the demand made on it from the resistor (windlass) then there will be no apparent drop of current as the wire handles the load
this is a a matter of fact, therefore To compensate for voltage drop larger cross-sectional sized cables may be used which offer less resistance / impedance to current flow. eventually the larger the cable size, will negate the loss to an amount not worthy of this conversation or for people wiring a windlass (how do you think they transfer electricity through pylons with no voltage drop)
for example i have used 30 amp tin cored wire on a whole rewire of my boat , not including main batteries or windlasses , so the largest draw on any one appliance is 15 amps from my electrical toilets , as I have long runs I calculated that 30 amps is suffice with the appropriate fuse to mitigate any voltage drop and a safe boat , hey guess what it works !
so the OP wanted to know if he could put a 24 volt windlass in a 12 volt system , of course you can the only negative which has been discussed above which is a fact is it will be 2 batteries on the bow which might be heavy for you, but who knows you could have a steel boat which would not feel the difference ,

 

[JohnGC]

I am not going to argue this one any more but it is the law of physics and current running through a wire, if the wire is larger than the demand made on it from the resistor (windlass) then there will be no apparent drop of current as the wire handles the load
this is a a matter of fact, therefore To compensate for voltage drop larger cross-sectional sized cables may be used which offer less resistance / impedance to current flow. eventually the larger the cable size, will negate the loss to an amount not worthy of this conversation or for people wiring a windlass (how do you think they transfer electricity through pylons with no voltage drop)
for example i have used 30 amp tin cored wire on a whole rewire of my boat , not including main batteries or windlasses , so the largest draw on any one appliance is 15 amps from my electrical toilets , as I have long runs I calculated that 30 amps is suffice with the appropriate fuse to mitigate any voltage drop and a safe boat , hey guess what it works !
so the OP wanted to know if he could put a 24 volt windlass in a 12 volt system , of course you can the only negative which has been discussed above which is a fact is it will be 2 batteries on the bow which might be heavy for you, but who knows you could have a steel boat which would not feel the difference ,

"They" don't.

In 2005 857.8 MW was lost to heating in the UK grid cables alone. That was about 2% of the power generated and supplied to the grid that year. The principles are exactly the same for 12V and 24V windlass wiring losses.

So far as I'm aware, the only cable with zero ohms is a super-conductor.

John

 

[Kukri]

The OP decided not to do it a couple of pages back.

Thanks, everyone, for a very interesting discussion.

 

[moomba]

yes were talking 2% this is a negligible loss to any electricity being transferred if were are talking about 4 volts on a 12 volt system on a boat that is 25% loss that is why we talk about no voltage loss when wiring a boat if you correctly wire your cables 3% is the margin you should be working in nothing on your boat will ever notice that drop but will if it was 25%
to pull hairs from a pigs arse there will always be a loss of energy somewhere but it is counted as 0 if it is negligible or we could be here all day talking fractions (so I apologise for misleading the nation there will be a negligible drop in volts if you use a larger cable but this is not exponential so the longer the run and the right cable sizing will always be the same drop of lets say 2% no risk of fire no loss of power no electronics playing up because they need a certain voltage

 

[pvb]

... me I always er on the side of caution and size larger wire (no voltage drop) and fuse everywhere ...

In reality the voltage does not drop immediately to zero; however, in the ideal case the resistance of the wires is ignored therefore a higher wire will result in near zero Resistance , or in laymen s terms nothing to worry about here mate.

I am not going to argue this one any more but it is the law of physics and current running through a wire, if the wire is larger than the demand made on it from the resistor (windlass) then there will be no apparent drop of current as the wire handles the load
this is a a matter of fact, therefore To compensate for voltage drop larger cross-sectional sized cables may be used which offer less resistance / impedance to current flow. eventually the larger the cable size, will negate the loss to an amount not worthy of this conversation or for people wiring a windlass (how do you think they transfer electricity through pylons with no voltage drop)
for example i have used 30 amp tin cored wire on a whole rewire of my boat , not including main batteries or windlasses , so the largest draw on any one appliance is 15 amps from my electrical toilets , as I have long runs I calculated that 30 amps is suffice with the appropriate fuse to mitigate any voltage drop and a safe boat , hey guess what it works !
so the OP wanted to know if he could put a 24 volt windlass in a 12 volt system , of course you can the only negative which has been discussed above which is a fact is it will be 2 batteries on the bow which might be heavy for you, but who knows you could have a steel boat which would not feel the difference ,

...so I apologise for misleading the nation there will be a negligible drop in volts if you use a larger cable but this is not exponential so the longer the run and the right cable sizing will always be the same drop of lets say 2% no risk of fire no loss of power no electronics playing up because they need a certain voltage

This is a lot of jumbled nonsense, with some small glimmer of understanding breaking through, but it's poor advice and could mislead forumites who don't know any better. Larger cables don't have "no voltage drop", they have less voltage drop. You can never ignore the resistance in a cable; you need to calculate the optimum cable size to give an acceptable voltage drop at the maximum current likely to be needed - and the acceptable voltage drop varies according to the type of equipment being used. You say you've used "30 amp tin cored wire", but I assume you mean tinned copper cable with a 30A nominal rating. This is around 2.5mm² cross-sectional area. If your 15A toilet is say 12 metres away from the battery, it would result in a voltage drop of around 2.9v - which some people would consider too much. This is a 24% drop at 12v (or 12% at 24v), still way more than the 2% you think you're achieving.

 

[JohnGC]

This is a lot of jumbled nonsense, with some small glimmer of understanding breaking through, but it's poor advice and could mislead forumites who don't know any better. Larger cables don't have "no voltage drop", they have less voltage drop. You can never ignore the resistance in a cable; you need to calculate the optimum cable size to give an acceptable voltage drop at the maximum current likely to be needed - and the acceptable voltage drop varies according to the type of equipment being used. You say you've used "30 amp tin cored wire", but I assume you mean tinned copper cable with a 30A nominal rating. This is around 2.5mm² cross-sectional area. If your 15A toilet is say 12 metres away from the battery, it would result in a voltage drop of around 2.9v - which some people would consider too much. This is a 24% drop at 12v (or 12% at 24v), still way more than the 2% you think you're achieving.

+1

Rules of thumb are useful but no substitute for proper understanding and calculations. It's only a table of cable resistance, knowledge of the system voltages and Ohms law that are needed.

 

[moomba]

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,
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 so lets look at the numbers
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

 

[moomba]

+1

Rules of thumb are useful but no substitute for proper understanding and calculations. It's only a table of cable resistance, knowledge of the system voltages and Ohms law that are needed.

what do you think i used to wire my boat a haynes manual!! i hope to goodness you have all checked your wiring again stating things that you have no clue to the actually facts.

 

[john_morris_uk]

I find Haynes manuals are full of facts.

 

[lw395]

A separate battery bank in the bow just to save on a bit of thick cable going forward just doesn't make much sense.

.....

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?

 

[moomba]

I find Haynes manuals are full of facts.

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

 

[john_morris_uk]

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 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.

 

[moomba]

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?

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

 

[JohnGC]

what do you think i used to wire my boat a haynes manual!! i hope to goodness you have all checked your wiring again stating things that you have no clue to the actually facts.

Which "facts" don't I have a clue about?

I have no idea what you used, how could I? I expect a Haynes Manual would use Ohms law either directly or in the form of a pre-calculated table; did you?

Either you didn't understand the physics you mentioned earlier, or you express your understanding badly in this thread. Neither is a crime, but when you do this on a subject in which I have 40 years professional experience I may choose to correct or contradict you. Sorry if you don't like it; but as RichardS often says, "this is the internet"

 

[moomba]

Sorry in no way am I out to criticise anyone, 40 years experience mean nothing as I do not know you or your level of work I cannot comment on that aspect of your writing. I took no offence to your writing we all have differences of opinion I have 48 years of experience does that make me a better person no I don't think so, so please don't get offended when I criticise you as we say its only the internet nothing personnel,
If you did not understand anything I said I would be more than happy to try and explain in plain english , as always typing can create a vibe that we are all angry and better , not the case

 

[JohnGC]

Sorry in no way am I out to criticise anyone, 40 years experience mean nothing as I do not know you or your level of work I cannot comment on that aspect of your writing. I took no offence to your writing we all have differences of opinion I have 48 years of experience does that make me a better person no I don't think so, so please don't get offended when I criticise you as we say its only the internet nothing personnel,
If you did not understand anything I said I would be more than happy to try and explain in plain english

Were trying to do something else previously? Seems unlikely. So what conclusion should I draw about your advice when some of it is wrong? Zero volt drop for example.

There are other comments in your posts which lead me to suspect you do have some understanding, but they are interspersed with others which either don't make sense or are wrong.

as always typing can create a vibe that we are all angry and better , not the case

Certainly it often does. I know my posts can sometimes be brief and that can be interpreted as abrasive which is not what I intend.