Cable selection on boat for 1000W motor

[bill01803]

Hi all, I was asked in the office last night what size cable would be required for a 12V 1000W windlass with a cable length of 14m. I know how to calculate but where do you find the tables for 12V volt drop etc?

 

[telectrix]

you're going to need one hell of a big cable. use resistance per metre from tables, multiply by 14, then V=IR, where I=83A

 

[Jim_e_Jib]

you're going to need one hell of a big cable. use resistance per metre from tables, multiply by 14, then V=IR, where I=83A

And a hefty power supply!

 

[snowhead]

I was going to say 1000w must be a misprint for 100w but then I found this;

Lofrans Kobra Windlass 12V 1000W - https://www.force4.co.uk/lofrans-kobra-windlass-12v-1000w-m.html

117 amps at 12volt.

You'll be needing 25mm minimum

Flexible tinned battery and starter cable, designed for use in marine and other harsh environments. - http://www.vehicle-wiring-products.eu/product.php/1031/tinned-battery-starter-cable

 

[Jim_e_Jib]

I was going to say 1000w must be a misprint for 100w but then I found this;

Lofrans Kobra Windlass 12V 1000W - https://www.force4.co.uk/lofrans-kobra-windlass-12v-1000w-m.html

117 amps at 12volt.

Yikes!

 

[snowhead]

Yikes!

Exactly.

There's a Calculator half way down this link;
Cable sizing and selection | 12 volt planet - https://www.12voltplanet.co.uk/cable-sizing-selection.html

 

[telectrix]

going to need at least 50mm cable. don'tforget, the warme the cable gets, the higher the resistance and hence increased VD.

 

[PEG]

Hi,it is a pretty standard install. Use 50mm high quality welding cable,and get someone to sort the runs and containment,correctly.
Long runs of multi-stranded flexible,can be very hygroscopic,and will need correct attention,at terminations.

Make sure the installer understands the word "hygroscopic"....as the yankee spell-check,has failed

 

[davesparks]

Hi all, I was asked in the office last night what size cable would be required for a 12V 1000W windlass with a cable length of 14m. I know how to calculate but where do you find the tables for 12V volt drop etc?

It's the same volt drop table as any other voltage, the resistance of the cable doesn't change.

 

[PEG]

Other details,i forgot to add,were it's duty ratings. It's not a bow-thruster,so it will have short duty-cycles (all in the MI) and 1000W is the maximum,so majority of use will be way below,at no-load operation.

Anchor winch,would be a whole different basket of whelks...

 

[telectrix]

just scrap the motors and employ pirate on a zero hours contract with a big capstan.

 

[MJPD29]

That will be a seriously expensive cable for all it is doing

 

[PEG]

Well,i suppose it's all relative....

It's forecast a change,to 10,and you need to do a rake of furling and unfurling,to get back to safe waters....

The cable,is an average length of site,MMA welding cable....

I wonder which job,is the one where you thought "Mmmm,i'm glad i spent that money..."

 

[pirate]

Just the job for me indeed...provided it's Capstan Full Strength!
However, just for clarification, is this an anchor windlass or a furler we're talking about? Clearly, the Lofrans linked to above is the former...