Windlass 12v wire - what size

[alisdair4]

I'm planning to fit a South Pacific Windlass to my Rival. I have chosen the VS 1000C . The recommended wire for the 12V supply is 13mm (sq). However, the cable run from the Batteries to the windlass are going to be quite long - around 7m I think. Is there any merit in increasing the diameter of the wire to reduce a drop in current? If so, by how much?

Thanks.

Alisdair

 

[Maree]

I'm sure someone will be along in a minute with the full calcs, but from memory your 1000 watt windlass will need about a 50mm2 cable to stay within a 3% voltage drop for a 7 metre cable run (I'm assuming 14m there and back) ....

 

[jeanpaulcopie]

I'm planning to fit a South Pacific Windlass to my Rival. I have chosen the VS 1000C . The recommended wire for the 12V supply is 13mm (sq). However, the cable run from the Batteries to the windlass are going to be quite long - around 7m I think. Is there any merit in increasing the diameter of the wire to reduce a drop in current? If so, by how much?

Thanks.

Alisdair

Having read your message, I understand that your windlass powers 1000 watts. If this is correct, I suggest you fit a 35mm² cable. The length to consider is the length from the batteries to the windlass AND BACK. In your case that would be 14 metres. You should also fit a 100 amp circuit breaker/fuse on the positive lead as a safety in case of overload (and have a spare!).I'm no professional but have completely fitted out a boat and the figures I give were given to me by professionnels in France where I live.

 

[afterpegassus]

Fitted a 1000w lLofrans last year. Manufacturers literature specified 35mm for my run in a 32'. This was achieved in a very cost effective manner with welding cable and care taken to seal the crimps.

 

[Scotty_Tradewind]

friend fitted windlass to Nic 38 recentLy
sent me this in case it's of any use in this discussion to anyone either now or in the future.........
"I went through the battery debate and in the end found it cheaper to run 20 sq mm wire from the existing batteries to the windlass even though I had to buy 18m of the stuff. It was available in red and black. I found it cheaper to buy it all in black (in quantity) and put red insulating tape at either end of the positive. When I bought the windlass there was a table in the instructions showing the cross sectional area of the wire required for various lengths of run - obviously the longer the run the bigger the cross section. I was on the cusp of 20 and 25 sq mm and have had no trouble with the smaller wire.

The windlass is terrific. If you buy one make sure it has a rope drum as well as the gipsy. I usually pick up buoys with no tail by feeding warp through the metal eye on the buoy doing this opposite the cockpit where the freeboard is lowest and there are gates in the guardwires, then letting the boat fall back with the tide/wind. We did this twice recently in F8. To get a second warp through for safety once we were lying to the buoy proved impossible; the boat was too far back from the buoy and the whole thing too heavy in that wind. I just put the mooring warp round the rope drum, pulled the boat forward and lifted the buoy up to deck level with the windlass. Easy to feed the second rope through with no frantic leaning and stretching over the bow."

 

[pampas]

If I remember. its takes 19 amps. I ran cooker cable from one battery, ran under cabin sole, Yellow 10mm crimps and soldered. I know every body will say its a no-no. but if securely clipped, especialy near your control box.

 

[Chris_Robb]

If I remember. its takes 19 amps. I ran cooker cable from one battery, ran under cabin sole, Yellow 10mm crimps and soldered. I know every body will say its a no-no. but if securely clipped, especialy near your control box.

If you can fit yellow crimps on, then the wire is far to thin for the job. 19 amps at 240 Volts ..... is not the same at 12 volts.

 

[Boathook]

I'm planning to fit a South Pacific Windlass to my Rival. I have chosen the VS 1000C . The recommended wire for the 12V supply is 13mm (sq). However, the cable run from the Batteries to the windlass are going to be quite long - around 7m I think. Is there any merit in increasing the diameter of the wire to reduce a drop in current? If so, by how much?

Thanks.

Alisdair

A bit of software that I have gives 50mm square cable. This give just over a 3% voltage drop. Assumptions were 14m cable run (there and back) at 1000W. Either way put in the biggest cable, within reason that you can. Voltage drop is a killer on 12 volt systems. Also as mentioned use a decent fuse / circuit breaker.

 

[Cliveshep]

I'm planning to fit a South Pacific Windlass to my Rival. I have chosen the VS 1000C . The recommended wire for the 12V supply is 13mm (sq). However, the cable run from the Batteries to the windlass are going to be quite long - around 7m I think. Is there any merit in increasing the diameter of the wire to reduce a drop in current? If so, by how much?

Thanks.

Alisdair

Assuming length 26ft, amps 85, volts 12, for 2% voltage drop (preferred) you will need 53mm2 conductor (50mm). To change parameters, use the calculator here: http://www.stealth316.com/2-wire-resistance.htm

Like the man said, buy lugs and cable from an electrical wholesaler and hire, buy or borrow a ratchet crimper, some will also tell you to solder as well, seems a reasonable idea.

 

[savageseadog]

Percentages can be difficult to quantify in my opinion. In any 12V system the aim should be to lose no more than 0.5V or preferably 0.25V at the load. It's a direct calculation to ohms from the current and hence wire size.

Just expressing my opinion

 

[john_morris_uk]

If I remember. its takes 19 amps. I ran cooker cable from one battery, ran under cabin sole, Yellow 10mm crimps and soldered. I know every body will say its a no-no. but if securely clipped, especialy near your control box.

Its not just a question of whether the copper has sufficient cross section. The reason that domestic cooker cable is not recommended is that eventually the copper will work harden and break. Boats vibrate and more rather more than houses do. The recommended wire is tinned multi strand, but at the overall copper cross section that is required for a windlass the prices are eye-watering.

Our windlass is fed with large diameter multistrand welding cable (which I inherited) and my suggestion to people who go down the non tinned multistrand route is to put some vaseline round the terminal/wire ends to try and keep the copper from oxidising.

 

[Rafiki]

cable size for windlass

I fitted an electric windlass 18m ago. I can't rememeber what the watts were therefore want get involved in that debate. but a few prcatical points;

1) Be careful you buy enough - I only just did! Working your way round teh boat to hide the cable makes the run 10-20% longer than you might expect.
2) Over on ebay you will find suppliers of welding equipment including cables - v much cheaper than marine of course
3) They also sell re-useable bolt on cable lugs - excellent. They are a bit more bulky that crimp on but much easier for DIY

Oh well I will tell you anyway - I used 25 sq mm cable. This fell well within the range specified in the windlass instructions and was relatively easy to handle etc. What surprised me was that the windlass came with a couple of metres of cable already of a much smaller size to be connected to the relay so I figured there was no point in overdoing the rest of the run back to the battery.

Regards

 

[Scotty_Tradewind]

electricity Volts, Amps, Watts, Ohms

W=V x A

V=Wdivided by A

V=A x O ????
am I right??

 

[Chris_Robb]

quote What surprised me was that the windlass came with a couple of metres of cable already of a much smaller size to be connected to the relay so I figured there was no point in overdoing the rest of the run back to the battery.

The windlass would only have had a short lenght. Just because this bit is under spec, it is still imperative to put the correct size in the rest.

25sq mm sound light - I used that size for a battery to battery charger with only 10 amps to connect the engine battery with the bow thruster/winch battery.

Worth noting that there are 2 tyoes of cable - soft and hard. The soft cable is much more flexible and easier to feed through the boat. Furneaux Riddel in Portsmouth stock this.

 

[Scotty_Tradewind]

quote What surprised me was that the windlass came with a couple of metres of cable already of a much smaller size to be connected to the relay so I figured there was no point in overdoing the rest of the run back to the battery.

At school I remember these basics..... am I right?
Very important to get as big or bigger cable size as req'd. Think of electricity running down the inside of a cable...... the larger the area/volume it has to travel along the easier it finds it, a bit like water down a pipe.
The smaller the area/volume then it struggles and you get heat and a poorer response/movement in the apperatus due to a volt drop.
Resistance wires in an element for a fan heater are coils of thin wire which will not disintegrate when they get hot. They glow due to the fact that electricity is forcing its way along the coils..... the down side is that it takes a high current to push it along which means it costs more in terms of battery charge.

 

[Rafiki]

thick vs this

Yes we know thicker is better but I still don't see why you would want to have thick for 7metres followed by significantly thinner for two metres.

 

[Networks]

Peter and Clive are on the right course. I get it to a 53mm cable. You MUST put your protection device, fuse or CB, I would suggest a CB (make sure it is DC rated) for when you stall the motor as your anchor hits the bow roller, at least you can reset it then.
The calcs are: V=IxR from this you can transpose Vdrop/I = R (max resistance for a given volatge drop). I=W/V, all of course for a DC system.

 

[Scotty_Tradewind]

Yes we know thicker is better but I still don't see why you would want to have thick for 7metres followed by significantly thinner for two metres.

agreed

 

[Fenlander]

An alternative method is to fit a seperate battery near to the windlass connected to the rest of the wiring via a diode, which then raises another question should it be a starter battery or a cyclic battery?

 

[pampas]

If you can fit yellow crimps on, then the wire is far to thin for the job. 19 amps at 240 Volts ..... is not the same at 12 volts.

The cooker cable is rated at 60 amps continuose, and if my voltmeter is correct the volt drop is so small that I could not measure it at the control panel, length of run about 18 feet.