yes, you should be OK. The new Rx pack - with 1100 mAh capacity. Is it 4-cell 4.8 Volts? If so, then everything is OK. To fully charge it, you may need to leave it on charge for 24 hours. Read the mA output on your Futaba charger. It is probably 50 mA. Divide 1100 divided by 50 and you get 22 hours. Allow a little extra.