2009 2L alternator

[mummywagon]

My water pump seized recently and snapped the belt. I replaced the pump and belt and all was fine until I started it this morning and the Battery light came on. Noticed the interior light was on so turned it off and assumed it would be fine with a bit of a run. All the lights came on, power steering failed and the car eventually cut out. The alternator appeared to not be putting out any charge, so I replaced that today. I charged the Battery off my partner's car for a bit and it started and ran fine very briefly. It is now cutting out as soon as I stop (it was idling low at 300/400rpm). Do you think I just need to replace the Battery too? I'm worried it's all related to the belt snapping, although it might be completely unrelated. I just don't want to keep throwing parts at it!

Thanks to anyone still reading! Would love to hear some opinions, thanks.

[TonyHSD]

Something it’s not right here. Whoever diagnosed the water pump failure and the belt snap needs to double check again the new pump, the pulleys and any automatic tensioner if the car has one. The new alternator too. Have you used original parts or what brands if aftermarket? 
 

[mummywagon]

Hi Tony, thanks for your reply.

I did the work myself with aftermarket parts (Euro car parts). The water pump seems fine and the car is holding temperature fine. I've checked the new alternator and it's putting out 13.5-14V as it should. The belt is and was tight before and after the new alternator. It tensions off of the alternator adjuster.

We took the car for another drive last night and it was fine, I'm just not sure whether to trust it with a baby in the car 

[TonyHSD]

Ok,  If you worked on the car it’s fine but if unsure about anything best to re check all the work done. Has the rpm settled? 

[Bernard Foy]

I’m no expert but I believe that the car needs time running to relearn all the stuff re the warnings.

[avetoy]

The rpm will settle after some time by itself. There is a way to teach it too... can be found via google.