If the charger you have will only do a 1000 mAh, That is 1 AMP charge rate and the 1800 can be charged at 1.8 amps.
Your charger will take over 2 hrs to charge. You can charge stright through the out put wire's with no problem. The small connector's can be used to just check balance if you think it is needed. If you charge both packs at same time that is 3600 mAh and could be charged at 3.8 amps and would take about 4 hrs with your charger.
Milton