What you're experiencing is perfectly normal. The charger is tapering down the amps and balancing the cells. The duration of this will largely depend on the health and quality of the pack. I have noticed I have one shorty pack that is getting long in the tooth and will typically take longer to balance charge than my other packs. The icharger's are excellent. I use a 306b and have charged at rates up to the maximum 30 amps for my model. Don't be afraid to charge at higher rates if you have a capable power supply.