Ok I think there may be some misunderstanding here.
The board you've link to in the op is not a charging board. It's a charging protection circuit board. You do still need one but it's not going to charge your batteries. You'll need something like this.
http://www.batteryspace.com/smartcharge ... isted.aspx
An actual battery charger limits the current that is being input into the protection circuit, where as a DC 12v 3A power supply will just try to pump as much as it can into your poor batteries, in this case 3A. Lithium ion batteries take some delicate care to charge correctly. So your whole system will look like this.
Charger->protection circuit->battery cells->system
Now there are some more complications if you have the system running while your batteries are charging. Your charger will need to have enough amperage to power the load and charge the batteries at the same time. The problem with battery space smart chargers however is that they are meant to be standalone chargers and are not necessarily meant to be drawn from while charging, meaning either your system won't work or it will be bad for the charger.
Take a look here:
http://forums.modretro.com/viewtopic.php?f=36&t=14089
And the reason that nothing appears to be happening is that discharged 14.8v packs sit at about 12v, there will be no current flow between the power supply or the battery pack.