Apologies George
I can see the bigger picture now and hence agree with your comments. I'm familiar with the permanent charger connection option as that's what I have on my Roadster, part of the 4 amp Maypole charger kit and very similar to Ctek option.
I'm getting one of the small jump packs. I'm going to take off the clamp ons and replace them with the connector that also used on the charger. That way I can plug in the jump pack without having to take off the bonnet. As I'll be jumping what is a lawn mower battery I don't think I'll have a problem with the smaller wire size. We'll see :-)
Dutch, it's a great idea to have a permanent plug-in charger connection to benefit battery top up when car hasn't been used for a while. As George (Luddite) suggests though, please don't be tempted to adapt a jump start battery to these cables though.
Not sure what power your lawnmower battery has, but if it's to assist in any significant way an attempt to jump start your car with those one litre pots, current in the order of a hundred or more amps is going to burn up charger cables in short order!
From what you have told us the charge system is not working at all so if you need to move car a short distance to allow repair, would simply suggest charging up the battery fully with charger. Maybe take the jump start battery as a backup, but please only use as intended directly across battery.
