Offroad-Express

Just replaced my alternator on R50 Terrano with brand new item. Not genuine however. Dash lights and heaters dip in power when at idle. Voltage returns as revs lift. What is the problem here?

Dud alternator...

Bust out your multi meter and check the voltage and idle. As above possibly a dud. Rather than getting a repo you are often better off rebuilding your existing alternator.

Matt.

Probably normal, need to get a volt meter and check voltages
Alternator output depends on engine revs. So wont have much output at idle and with the lights and heater voltage will go down.
You need to check with a volt meter.

are all the wires hooked to the same spots,
some alternators need a signal wire to let them know when to start charging/regulating to 12volt

Check it with the engine warm. The after glow on these stays on for a while when first started and really draws some power. When warm the voltage should be 14-14.5 at about 1000 rpm with every thing turned on, if it cant do that its a dud.