Battery Relocation for R56 Exhaust Installation
For two cars, we installed an R56 exhaust. To accomplish this, the battery tray needed to be removed or shortened. On both MINIs, we relocated the battery behind the passenger seat and added an inline fuse for safety.
We were able to reuse the existing battery cable, cutting it to the appropriate length. This particular installation is for the @R53HomeBrew MINI, which initially used a UPS battery – the RITAR RT12240.
Battery Specifications
- Dimensions: 182.5mm (D) × 78.5mm (W) × 170mm (H, measured to terminal top)
- Weight: 7000g (±4% tolerance)
- Voltage: 12V DC
- Capacity: 24AH
- Float Voltage Range: 13.7 to 13.9 VDC
- Equalisation Charge Voltage: 14.6 to 14.8 VDC
- Max Charge Current: 6A (recommended)
- Max Discharge Current: 240A (burst; CCA is higher)
Proof of Concept
Installation Process
The mounting frame was secured using riv-nuts. Important safety note: Be extremely careful not to drill into the fuel tank behind the mounting location. I learned this the hard way when my backing plate dropped without me realizing – definitely not a fun experience! Once mounted, the battery was connected to a kill switch at the front of the car.
Real-World Results
As the car neared completion, I started experiencing starting issues that pointed to battery problems. Interestingly, @r53budgetbuild hasn’t had any issues with his UPS battery setup – three years on, his car still fires up first time, every time.
I eventually switched to an Odyssey race battery, which completely solved my problems. Curiously, the UPS battery that failed in my car worked perfectly in @r53budgetbuild’s MINI during final testing. I can’t explain why – it makes no logical sense.
