I also use a Ctek, bought from BHM complete with extra leads for a socket or ciggy lighter. Aeros need trickle charging when garaged as the clock and immobiliser drains the battery. The battery is a gel battery so when discharged can be difficult to regenerate ( use an old fashioned very slow trickle charger ) and they are very expensive to replace. The Ctek type charger will not charge if the battery has gone under 7.7 volts. I thought all Aeros came with a trickle charger as standard? I would recommend the Ctek and use via your '12v power outlet ' which is always live on the Aero. I also have a similar charger sold occasionally by LIDL at around £12.95, excellent value but only comes with crocodile clips neccessitating opening the bonnet. Maybe the likes of Maplins may have the bits to adapt.
