Not sure of your battery's capacity & C rating, but hopefully you have enough power to charge a 4S LiPo pack at a 1C charge rate. For a 5000mAh 4S LiPo pack charging at a 1C charge rate (charger set to 5 amps), you will need a charger with at least 84 watts of power.
If you have a 50 watt charger; capable of 10 amps charging current, and try to charge a 5000mAh 4S LiPo pack at 1C charge rate (charger set to 5 amps)... you'll see your charger peaking out at around 3 amps even though you have the charger set at 5 amps.
Some dual channel chargers will say they have 150 watts of power (75 watts per channel using AC input). Using same LiPo pack example as before... If you have a 75 watt charger; capable of 10 amps charging current, and try to charge a 5000mAh 4S LiPo pack at 1C charge rate (charger set to 5 amps)... you'll see your charger peaking out at around 4.4 amps even though you have the charger set at 5 amps.
Charging 4S LiPo batteries requires quite a bit more power than the "run of the mill" lower budget chargers out there even if you want to do 1C charge rates. Me... my normal charging practices are 2C charge rates. I can come home from work; throw a 4S, or 6S pack on the charger... 25~30 minutes later I'm ready to kick up dirt!
My one 6S pack is 7500mAh. At a 2C charge rate, I charge that pack at 15 amps... quite a bit of power needed (252 watts to be almost exact). That 252 watts is one of the "numbers" that I use when shopping for a charger that will meet my needs.