I have now bought a Litium Ion battery 12V -4Ah (compare to 12Ah), weight 0,9 Kg. A batterybox is fabricated from a 0,63mm AL 6061 sheet. Rivet to firewall, and secured with a strap around. Battery wires AWG 4 used to connect battery and starter, AWG 8 used as ground wire to firewall.
