Originally Posted by doba_s
What downsides have you seen with MINI battery ?
Well, since these lightweight batteries are physically smaller (and less powerful) than the stock 90Ah battery, you have to manage the power drain a little more carefully.
Your margin for error is now less than it was with the factory equipped battery. So you can't make foolish decisions that can get you into trouble.
That means you have to monitor your usage when the key is off, and make sure you don't leave anything on inside the car that can drain the battery.
Many plug-in accessories will do this, as will listening to the radio/CD etc. with the engine off.
Regardless of which size battery you choose, you must be vigilant in keeping a tight reign on your current consumption. (the part YOU can control)
The Mini battery allows you a more comfortable margin of error between the 90Ah stocker, and the lightweight 20-30 Ah aftermarket alternatives.