Britpart alternator terminals

Hi,

Trying to install a new Britpart alternator to a Trialer with a 3.5 V8 RR engine. I have only two cables to connect........main battery cable and exciter cable. However, I can only see 1 of the terminals marked on the new alternator.......this is marked 'D+'. I assume the exciter cable goes to the D+, where does that battery cable connect to ?! Am I missing something, surely the terminals should be marked ? Thanks.

Don't know if this is of any help?
Alternator Rectifier Lucas A127 Type 3 Screw Terminals, Mobiletron Rl-21H 7426994732568 | eBay

There was me thinking D+ was dynamo related!

One the last alternator i bought it was obvious, but also, the nuts on the connection post were quite loose, barely finger tight

This is how mine is wired:

Thanks chaps, really helpful......all working now