Voltage for 30 HP

"I recently had a problem with

"I recently had a problem with my 30 HP Evinrude Electric start. The motor was not charging my battery, and I had a rectifier installed at a marina.
I am trying to find out what the voltage should be while the motor is running.
The voltage meter on my eagle fishfinder is showing 12.2 to 12.4. Is that the proper voltage??

Thanks for any advice.

Merv"

"The generator on this engine

"The generator on this engine is more a maintanance charger than a battery charger. There is no regulator (as original) just a diode rectifier. Any charging below 1500 rpm should not be expected, but depending on battery charge and type, it may climb up to 13,5-14 volts at full throtle. Do not do the mistake and install too big battery. A normal small car battery, 60Amp/hrs, cheapest type, may probably be the best."

What is the voltage with the e

What is the voltage with the engine off? If it is the same as when its running you are not charging.
A new battery will sometimes have more than 12 volts and will recharge itself as long as it is not drained to far down.
ie if it goes down to 11 volts it may come back to 12 volts after it has sat a few hours.
A battery will only do this for the first year at the most depending on how good a battery it is and how often and far it is run down.
It may be better to check the voltage with a test meter at the battery than using the fish finder to measure the voltage.
Check the voltage at the battery before you start the engine then recheck it again after starting it. If there are lights on the boat turn them on. The voltage should not be less than before you started the engine. If it is you are not charging.
The charging system should be able to keep 12 volts at the battery with the lights on at the factory idle setting.
If not long times spent idleing at night with the lights on would kill the battery and defeat one of the reasons for the charging system.