Mahindra 3525 Battery Charge Light

[LFP57]

I just purchased a brand new Kubota, a few days ago, a very good friend of mine needed some fast cash to purchase a new house and offered me his 2007 Mahindra 3525, three implements and a trailer for a very good price. Now I have two tractors, what I would like to know is, when starting this Mahindra, the battery charge light comes on and his words were: "you need to raise the rpm's to excite the alternator" and when you do, the light does go out. The charging system is working when it's running, so, is this normal for this tractor?