Battery charge system error after replacing alternator

[BillyMillin]

Hi folks, this one is pretty self explanatory. The alternator collapsed on the car so I replaced it and now I get an intermittent "Service Battery Charge System" message on the dash. The plug is in the new alternator correctly and the other wire with the nut holding it on is on too, the belt is on correctly as well. In fact I took it for a drive last night and the lights were brighter than before and wipers were faster too, which tells me the battery wasn't getting a good charge off the old alternator. Any ideas?

[Vauxhall Owners Club]

It may be the battery charge sensing the old charge rate and needs resetting to sense the new charge rate.

You will need a scanner to reset the battery charge sensing