If you’re looking for the ultimate battery that will just squeeze into a Mini battery box then you should just buy one of these. The cells inside are wound in a spiral shape, surrounded by absorbent glass matting to prevent the fluid from moving around, and the whole unit is completely sealed (you can mount them at any angle you like). With a whopping 815 amps at -18 degrees C and a more impressive 1000 amps at 0 degrees C, this thing cranked our engine with consummate ease.
The capacity is rated at 50Ah, but we put back in nearly 10 per cent more than that after our 10.5 volt stable discharge (meaning our battery had a higher capacity). The impressive thing about this battery aside from the power is that is recovered from each engine cranking burst very quickly indeed, coming back up to stable voltage much quicker than any other battery in test.
Optima Red Top RT S 4.2
Reviewed by: MINI Magazine
Summary: Expensive, but worth every penny.
Description: The capacity and overall results are beyond expected and label marked.