Alternator wiring

[neilc]

Evening ,

 I have fitted a new alternator and realised that the plug was covered in oil , I ordered a new one ( when i look at it now ill probably clean the old one up and add new spades as the new one is a bit flimsy)

and removed the old plug , I have put the new plug on , however the wires and coating  were very brittle and I had to cut off about 2cm to get the new connectors on , it works , however im not that happy with it. i know where all the wires go and what they do , however can I just order a 17 AMP thick wire and 2 smaller wires (approx 1 metre) and just send the same 2 to the starter solenoid and the other to the charger light or even splice them in to give me more wire length or isnt it that simple?

Also can someone please advise how thick all the wires need to be , a new harness is £40 , seems a bit steep for 3 metres of wire and a few spades (as i say i already have the old plug cleaned up)

Thanks

 

Edited May 12, 2020 by neilc

[Arjan]

Yes - any correct grade cable will do.

However, depending on what you want to achieve, you may want to go for a correct colour etc. ""set".

We use 25 mm2 for the alternator to battery as the charge cable. However, we do not do original etc.

The rest (charge light & tacho) is 2 mm2.

 

[secondjeremy]

https://www.vehiclewiringproducts.co.uk/

Loads of information on site and even more in catalogue - which can be downloaded - see near bottom of column on left.

Convention seems to be that wiring shouldn't be loaded at more than 1/2 its rated capacity - ie 20 amp load needs 40amp cable.

 

 

[Snagger]

17a cable is nowhere near heavy enough.

[Arjan]

Alternator is up to 100 amps.

Do the sums.

Be safe.

[neilc]

Hello again ,

Just looking at this , thick and thin brown wires go to the starter solenoid , a lot of people state they have theirs going directly to he starter motor itself , does it make any difference? , if it doesnt it would be a lot easier for me to take the wires to the starter rather than the solenoid .

[steve b]

yours is a petrol ? the starter cable is only live to the battery when cranking . Run it to either the battery +ve or the battery side of the starter main load relay

cheers

Steve b

[Snagger]

18 hours ago, neilc said:

Hello again ,

Just looking at this , thick and thin brown wires go to the starter solenoid , a lot of people state they have theirs going directly to he starter motor itself , does it make any difference? , if it doesnt it would be a lot easier for me to take the wires to the starter rather than the solenoid .

Series Land Rovers have solenoids separate from the starter motor, but 90,110 and Defender all have the solenoid incorporated into the starter motor.  The battery, dash power and alternator cables all attach to a terminal on the solenoid of the later units too, not the motor itself.  You must attach the alternator to the battery side of the solenoid, or it will not charge the battery with the solenoid open, and worse, will be sending it’s output directly to the starter with no way to disconnect it, trashing the starter and the flywheel gear.  It doesn’t really matter whether you route to the solenoid’s battery terminal or the battery itself - electrically, its the same - so do whichever is most practical.