OEM CSL Battery (Mini Cooper) - 61218377139 - £102.07 Before discount
I run a Braille B2317RP - £128 + VAT
First one lasted a year and never seemed to hold charge. Sent off to Braille, tested and replaced me with new one.
Had new one 16 months and not missed a beat.
I use a Ctek xs3600 and its fine. Battery still going strong.
Battery Weights
OEM Battery - 15.6kg
Braille Lightweight - 7.7kg = 7.9kg Saving
You can run standard Battery brace but modify it. (see below)
This is mine with an aluminium brace I fabricated, whilst on the weight saving program.