Originally Posted by
Roelof
2 things can be the cause.
1) a bad balance, balancing cells can take a while if they are far off from each other.
2) you are usenin a simple 50 or 60 watt charger. Charging 6A with 12.6v needs 73 watt of power, chargers with a lower power rating will lower the current.
To further this, If your charger only has 50W of power, it will limit the charge current to around 3.8A (13.2v x 3.8A = 50W) for a 3S lipo, which translate to roughly around 78min charge time which somewhat matches what you are experiencing now. You will need a charger with more output power (Watt, not current) so you can charge at a higher current and shorter charge times.