Most two-cycle outboard
engines, 9.9 hp and below, use simple pickup coils, one diode, and the rotating magnets on the engine
rotor to generate voltage. Regulating these "lighting coils" (which is what they were designed to do...drive running lights and not really charge batteries) require shunt regulators. Most solar
panel regulators are series regulators. If you use a series regulator on the output of a lighting
coil the diode may get destroyed by BEMF unless you wire in a small shunt load, like a 14V light bulb (O.K. a "12V" bulb that will survive up to 16V).
You may have to de-rate the output power rating of a solar
series regulator to use with the lighting
coil output due to the higher pulse currents delivered on a continuous power rating basis (like use a 100-plus Watt rated regulator on a 50W rated outboard coil).
I don't know about the 4-cycle 9.9 dc outputs, whether or not the manufacturers have actually put in the expense of a real alternator...any comments?