The detail of participants of Badr is written in Maghazi ibn Ishaq and Maghazi Musa ibn Uqba. Hafiz ibn Hajar Asqalani and the author of Al-Bidaya O Al-Nihaya have fixed the number of Badri sahaba accordingly. The detail can be seen in Siraat Ibn Hisham.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband