When you charge a pack at less than 1C, it simply takes longer to charge. A properly-working lipo charger will charge to full capacity no matter the charge rate.

Charging a 5000 mAh pack at charge rate of 3000 mA is 3000/5000 = 0.6C. Since a 1C charge takes a little over an hour, a 0.6C charge should take about 2 hours.

- Jeff