if (b->charge_full < MIN_CAPACITY)
b->percentage = 0;
else {
int promille = (b->energy_now * 1000) / b->energy_full;
int promille = (b->charge_now * 1000) / b->charge_full;
b->percentage = (promille + 5) / 10; /* round properly */
}
if (b->percentage > 100)