Li-ion 4 Cells battery pack - Motorcycle use - Lead acid replacement

Used to replace lead acid battery on my motorbike: Lighter, last longer, no auto discharge.

I recycle 4 laptop Li-ion cells from a old computer. Charge and discharge controller 4S/30A has been purchase on eBay for less than 2.5 Euros.

Remark: Does not work correctly as a 12v batttery replacement. 4 cells requires too high voltage to recharge. Prefer 3 cells charger.