A127 Alternator wiring

Post by **roymck** » Mon Mar 04, 2019 8:56 am

Seen conflicting diagrams on A127 Alternator wiring . Is it ok to use the existing plug and just fit and forget or should you run a additional wire from the + post direct to the battery . Also as the Alternator may run at up to 70 Amps the Alternator plug has the spare terminal so is it a good idea to double up on the brown wire direct to the battery from there.

Post by **Oldconn** » Mon Mar 04, 2019 9:15 am

I don't think the spare + post is regulated - perhaps somebody could verify that. I have been running a 70amp A127 for about six months, just on the old plug as it was. No problems up to now, because the only time I had absolutely everything switched on for any length of time was in a blizzard on the autoroute, so I don't know if the wiring got hot or not. I wasn't going to stop to find out! Just one point of caution - if you don't use the spare + terminal, isolate it carefully to avoid an accidental short to earth when you have the bonnet up.

Post by **roymck** » Mon Mar 04, 2019 9:28 am

Yes I think your right it’s not regulated ,are you running 3 wires from the Alternator plug , one warning light wire and 2 wires to the battery or just one wire to the battery ?

Post by **AJL Electronics** » Mon Mar 04, 2019 9:30 am

The B+ stud on the back is in parallel with the plug and should be used if you want the full capabilities of the alternator. You can run a parallel feed from it without disturbing the original wiring.

Post by **scimjim** » Mon Mar 04, 2019 9:47 am

Technically, you need to calculate your maximum possible load and ensure your existing thick brown wire is big enough to carry that load.

Or, just run another wire from the second spade terminal to the battery

Post by **roymck** » Mon Mar 04, 2019 11:33 am

Quite right Jim , I intend to run an additional wire direct to the battery using the spare spade connector . Bought a new Alternator plug but wanted to crimp and solder to make sure I got a good connection and the new plug has aluminium tags just don’t think that will be as good , can’t beat cooper for terminals

Post by **Oldconn** » Mon Mar 04, 2019 8:16 pm

roymck wrote: ↑
Mon Mar 04, 2019 9:28 am
Yes I think your right it’s not regulated ,are you running 3 wires from the Alternator plug , one warning light wire and 2 wires to the battery or just one wire to the battery ?

I have two browns connected to the plug, plus the warning light wire. AJL reckonsthe B+is in parallel , so should not be a problem.