I've been concerned about having back up for the engine electronic ignition. I've been accustomed to magneto simplicity and no reliance on an energy source. I decided to install a small EarthX 12v battery that I can switch to in the event of battery/alternator failure. I installed diodes and a switch that allows the battery to be charged by the alternator when not in use, but will isolate the battery to one ignition side from the rest of the electrical system when called on. The battery is mounted on a try just forward of the instrument panel. I plan to instal a connector to all me to periodically check the voltage, as well as connect a trickle charger specific for lithium batteries for winter storage.