Moody Blue
Captain
- Joined
- May 24, 2004
- Messages
- 3,136
Re: 1973 Mercury Thunderbolt 500 50hp no power and horrible fuel economy!
Nope that's not how a rectifier works. A rectifier merely converts the AC voltage from the stator, to DC voltage for the battery. It does not switch on or off and has no ability to alter the voltage. The higher the RPM of the motor, the higher the voltage to the battery will be. A regulator (commonly combined with a rectifier) will maintain a specified output (typically around 14V) as long as the input voltage to it is more than 14V, regardless of the motor RPM.
The high voltage will tend to boil off the water in the battery with extended running time so be sure to monitor the water level in the battery. The maintenance free type batteries are not recommended for use with these older motors but probably all of them on the water today use the maintenance free type.
I ended up installing an after-market regulator/rectifier because of the excessively high voltage. The onboard electronics don't like the voltage that high. I was measuring 17 volts at WOT on a fully charged battery.
It is not uncommon for the battery voltage to run up to 15 or 16 volts untill the rectifier shuts the charge down. thats the way they work. The rectifier will start charging again anytime that it see a drop in the voltage from running lights or any DC powered add on ACC.
Take it out and run it as if you own it. Its more fun that way. The new manual will come in handy more than you first thought.
Oldman570
Nope that's not how a rectifier works. A rectifier merely converts the AC voltage from the stator, to DC voltage for the battery. It does not switch on or off and has no ability to alter the voltage. The higher the RPM of the motor, the higher the voltage to the battery will be. A regulator (commonly combined with a rectifier) will maintain a specified output (typically around 14V) as long as the input voltage to it is more than 14V, regardless of the motor RPM.
The high voltage will tend to boil off the water in the battery with extended running time so be sure to monitor the water level in the battery. The maintenance free type batteries are not recommended for use with these older motors but probably all of them on the water today use the maintenance free type.
I ended up installing an after-market regulator/rectifier because of the excessively high voltage. The onboard electronics don't like the voltage that high. I was measuring 17 volts at WOT on a fully charged battery.