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The audi has not turned a wheel for 4 weeks, but the battery is in tip-top condition, as it has a "smart charger" connected to it for 48 hours every 14 days. Modern cars with all the anti-theft devices and other stuff quickly run down a battery, .......
Whilst we are on the subject of batteries, any recommendations for a smart charger for AGM Start/Stop batteries. Mine doesn't go far now so I'm thinking it should get a little charge now and again. I was looking at the Halfords Smart Plus but no idea if it's any good or not. I have two of the standard battery chargers but they're no good for AGM type I believe.
Reference the AA and batteries, I drove over 300 miles in one go in the Omega, parked up, went to move it twenty minutes later and it was completely dead. Well, 8V actually, but may as well have been dead. The AA turned up, did the checks for parasitic drain and fitted a new battery. He was a pleasant guy who was only too happy to check for battery drain, so a thumbs up from me. 
The Halfords branded Smart 100/200 etc are *desperately* unreliable. I had about 5 in 3 years. They are made by Ring. I replaced it with the Ring RSC612 that I got from Halfords (as I guess you have trade) which has been flawless. It defaults to non AGM (or Stop/Start in their parlance) every time you plug it in though.
As with all smart chargers, I don't bother with the various repair modes, as if you need to use those, your battery is shagged anyway.
Its pure croc clips only, no "comfort" leads like the Cteks....
...which brings me on to Cteks, I have had half a dozen of them, 3 for bikes and 3 for cars, all have been utterly useless. But the comfort leads are a real idea.