Re: what's up with this?
what your saying is the rectifier never knows when the battery is charged so it continues to put the full amps to it?? I have an old johnson...78...with all new electronics..and a walmart maxx marine...largest they had. My voltmeter reads 15 1/2 to 16 volts all the time...I would rather it drop down to about 14.5 or so at some point but it never does..I think mine is the 9 amp system so I wouldn't think I was pushing the battery to hard..but I could see the problem with a 35 amp system that never shut off. I really don't see though how it doesn't know. I figured most starting batteries were about the same...I know quality is different from brand to brand...but they aren't deep cycle, they are starting batteries pretty much like a normal automotive one. Just seems like it would not be the batteries fault as it would be the electronics.
Rectifiers don't turn on and off when the battery is fully charged, only regulators do. You can put a regulator on a 9 amp system. I have seen batteries explode on rectified systems because they never stop charging. If you have enough stuff running, the battery will never overcharge.
A rectifier is simply a set of diodes that converts the stators' AC voltage to DC voltage and does not sense battery voltage. It will charge indefinately.
A regulator is a rectifier with a voltage sensor in it. When the battery reaches a certain voltage, it shuts off the charge to the battery until the battery voltage drops to a pre-determined point and begins to charge again. Also, as the battery charges and reaches a certain voltage, the regulator will stop charging the battery.
If you have a battery that is not capable of reaching the voltage the regulator deems as fully chrged, the the regulator will continue to charge that battery.
We see this very often in boats with multiple batteries and using a battery isolator. the battery isolator will prevent voltage feedback to the regulator causing the regulatgor to continue charging,,,,,, but this is for another discussion......
No battery is created the same. Some batteries peak at 13 volts, some at 13.4 volts and some at 12.5 volts. The ones that peak lower are more susceptable to overcharging since the regulatoer considers (let's say) 13.4 volts as the cut-off. So a battery that is fully chaged at 12.5 volts will continue to be charged until it reaches 13.4 volts but never can by design, therefore get's over charged and resultantly explodes.
