Mike,

The charge time does not increase. A quick word of advice when using the 109's my chargers will charge the packs to different levels. one charger peaks at 20.95 volts and the other at 20.80volts. This is the chargers doing this. If you have a watt meter check the two packs after charging and see if they do this. If so what I would recommend would be after the charge is complete put the lower pack on the higher charger and let it run at 2 amps. We did this at the nats and it put almost 300 mah more into quiques pack.

Andrew