The endpoints are correct and the batteries are new. Before I used 1400mah batteries and due to this problem I have bought two 1800mah batteries and it fails with both batteries.
I have tried to measure the consumption with an ammeter and the consumption at rest is around 0.15A and exerting force on the car I get to have peaks of 0.6A, so with a 1800mah battery the autonomy should be greater than 1,5 hours