Keeping the dinghy battery charged

[Roy M]

My 15 hp propane Lehr has an electric start with a LiFePO4 battery. I don't know the output of the alternator (or generator) as it's so new that many of the specs are still being drawn up. I'd like to be able to run some light-duty electronics off of it, or add another battery, as long as I don't fry the alternator/generator. Does anyone have some info here? I could also use a battery combiner, I suspect, but I still need to determine the rated output.

[HopCar]

The Lehr alternator puts out up to 8 amps.