Hi everyone.

I don't drive my Audi very often, perhaps 50 miles a month, therefore my battery is always on discharge.

Although I have a smart charger, I can't always park behind my garden and leave it connected to a power plug (which is 20 metres away from where my car is). Also, I don't find it safe to leave it as anyone can cut the electric wire that runs to the car and I have no driveway to keep the car a bit safer.

I've got a spare car battery, that I can leave in the car connected to the terminals, whilst my main battery would be unplugged and on charge at home and when charged I would put it back in, repeating the process weekly or bi-weekly.

I'm looking to buy these extra terminals 110 Amp Car Battery Terminal Power Earth Cable Choose Colour Length Hole Size | eBay , and I would connect the terminals to the spare battery and those small ring terminals to the main terminals of my car, so when I disconnect the main battery the car would not lose the flow of the electricity.

It might sound a bit of a work to do this all the time, but would there be anything wrong if I were to do the charging this way e.g. Audi BEM errors or any possible faults that could occur if I were to connect a smaller battery by capacity, just so the car can be locked/unlocked?

Thanks