So I launched a refill on Energizer batteries maH 2300 and this time I was able to power the radio.
The charger is rather noisy because of the fan, the charger and the transformer is not plugged directly into an electrical outlet) is very cumbersome. So this is not a device that I will carry on trips.
Fast charge 1/4 hour) is a real plus if you're short stacks I think the part of Nintendo Wii that must stop because of empty batteries joysticks).