Hey guys hope all are well...... i just fitted a winch to ny defender and my question is because the negative
Cable from the control box was not long enough to reach my bettery box i have connected it to the main shasis grounding point on one of the engine mounts.. The winch works this way semmingly without a problem..... is it ok to leave it here or does it need extending to the battery?

Thanks

For something that draws that much power, I'd say running a separate earth back to the battery would be best, else you'll be increasing the resistance of the circuit unnecessarily.

Ok what you need to achieve is wire all the way to the battery capable of the max draw from the winch which could be in the 300a range. You could either run more adaquate cable to the same earth point from the main battery earth or run a whole new cable asking as the point is clean and has perfect contact.

What you have so far i suspect is a inadequate earth cable from the battery to chassis this will get hot as its most probably not rate high enough for dragging a motor through tons of porridge. I would run a new line or another line to the earth point.

Likewise the positive could equally be subject to the same problem if you have piled up the positive from the starter. No
Problem doing this IF your main lead from the battery to
The starter is up to the rating of the winch current if not then you will again be likely to cause a fire or melt the wiring and at very least not get the performance from the winch when you draw high current under load.

Point with noting a cut out switch is advised! Make sure it's rated seriously higher than the cable. Forget these 100a red key ones and
Even the fian comp cut out switches they're simply not up to it. Look at 500a continuous current mine is rates at 24v 400a continuous serious switch.

There are many winch installs That are poor a good install some thought and some
Time spent on install will outperform and be reliable for when you need it!

It amazes me even some supposedly winch challenge spec motors that have in seawater wire poor routing and cut out switches that limit current and burn out spend a fortune on updated motors and run cheap wire poorly that limits performance that chafes and will eventually catch fire.

Sort the above problems and you will be in the top few that have it sorted correctly when others have poor pulling power or smoking wires you can be sure yours is up to the job.

Hello mate cheers for the reply... some good detail there.... so what im gona do is just install new cable running from winch to battery direct... through an isolator obviously. lil confused on cable size though..... its a tmax 11000lbs winch and i just looked up manufacturers spec..... it claims that you only need to use 25mm cable but also says that at max load the motor can draw upto 400a.... i was looking at cable ratings and youd need 40mm cable to handle 300a on a 12vdc circuit..... so y is the manufacturer supplying and recomending such small cable size?

chris freestone said:

.... i was looking at cable ratings and youd need 40mm cable to handle 300a on a 12vdc circuit..... so y is the manufacturer supplying and recomending such small cable size?

Click to expand...

So that the cost of the cables does not put you off buying the winch! Smaller cable is OK for very intermittent light use but if you want to do some serious continuous heavy pulling then as Jai says you need some serious cabling.

Have a look at some of the welding cable thats available as it comes in long lengths, is reasonable on price, and is continuously rated at large currents. As its a fixed install you dont need to worry about the super flexible stuff.

Ok yeh that makes sense think i will be puttin in 40mm cable then...lukily i know a guy workin for an electrical wholesalers so i should get an alright deal... one last question this leads my mind to though is if im now gona upgrade all these cable sizes it means opening up the control as they all run from in there not woried about doing that but what about the current ratings for all the internal components ie the relays??? Are these gone be underated aswell?