Hello;

I am here from the Xjs forum, hope I can get some help here…..I have an AJ16 powered car and my alternator went out. I bought a new alternator, but it’s a 200AMP alternator. I really did not realize until I received it that it was 200 amp. The car has an extra cooling fan and a aftermarket radio and has been running with these additions on the stock 120 amp alternator for years. I am not adding anything new than when the car ran with the 120 stock alternator, so I am thinking the stock wiring should be fine since I will be pulling anymore than I was pulling before…

Will the factory cables be fine?

Thoughts greatly appreciated

 

Probably. Your thinking sounds right to me - aternator amperage doesn't really matter as long as it's over what your car draws with EVERYTHING running (its peak/maximum load), as current is 'pulled' rather than 'pushed' and electronics only pull the current they need. If you get a short then the system might dump a bit more current into it, but that's what fuses are for *shrug*

I'm mechanically and electrically experienced but I'm new to Jaguars so it's possible there's something specific to Jag that I'm not aware of (like maybe the computer checks alternator amperage through a digital handshake or codes or something like that).. but in general the above applies and I haven't yet seen an alternator that does silly stuff like handshakes.

 

Current has to be drawn, so the only way your alternator will output 200 amps is if you put 200 amps of load on it. As it sounds as if you are not changing anything else, the wiring etc should be fine.