8 replies to this topic

[CFB0800]

My 1989 mini alternator has given up, I'm looking for a replacement and have narrowed it down with the Haynes manual to "Lucas A127/45 or A127/55"

I'm unsure of the amp I need, can I simply replace it with the larger one and it will make no odds? Or do I have to put in a new battery and electronic systems to upgrade to the 55 amp?

[freaker]

no will be fine.

run the 55 amp one.

freaker

[CFB0800]

I've just looked its the 45 but I can just swap for a 55 and everything will still run fine?

[freaker]

yes no problem

freaker

[Elliskwleisk]

Is it also a simple swap if you put an 80 amp one in?

[nev_payne]

Yes- but if you're going with a higher current, best to chack the basic charging wiring circuit is in good condition - braded earth cables and battery +ve to solenoid inparticular. Bit of a waste otherwise.

[Dan]

No, if you are going to fit a much higher power alternator than the wiring was designed for like that (the 75A or more types I mean) you should increase the size of the cables from the alternator to the starter solenoid. This is the only part of the system that will need improvement.

[nev_payne]

Just going by what I was told back along, no intent of misinforming.

[tiger99]

Well, at 55A the wiring is still ok, just, so I don't think there was any disinformation, but at 75A you very definitely do need to upgrade the wiring, the thick brown wires from the alternator to the battery terminal on the starter solenoid only. 55A is adequate for most cars anyway.