Originally Posted By: 1 FMF
funny,
do you know how it works?
it's a diode, and with any diode when current goes through it there is a voltage drop. Typical silicon diodes have a 0.7 volt drop all the time. Germanium diodes have a 0.3 volt drop, and there's probably a handful of other materials that have various voltage drops. The purpose of a diode usually is to prevent the backflow of electrical current, the voltage drop is a negative side effect usually. in this case they are using that voltage drop, along the voltage sensing circuit i'm guessing (they say install on ALT fuse in fuse box). So because of the voltage drop of the diode the voltage regulator sees less system voltage and increases output to maintain what it wants system voltage to be.
the only upside i can see is if you had some off-road lights and you wanted them as bright as possible.
the cons on the other hand, you're burning more fuel having the alternator output at a higher voltage. Many late model cars have implemented variable charging where the engine computer commands the alternator output to be lower which takes less effort to spin the alternator and save fuel.
And a fully charged lead-acid battery is 12.65 volts +/- a little depending on temperature. So anything above 13.0 volts will charge and maintain the battery. In hot weather having system voltage over 13.8 volts will gas the battery and kill it!
And in making the alternator output higher voltage like this, you're making the alternator work harder all the time which creates more heat in the alternator and will cause the rectifier (also diodes) within the alternator to burn out.
it is the AGM type batteries that can use a 0.1 - 0.3 volts higher charge voltage, not necessarily "GM type sealed maintenance free battery". If that type of GM battery is AGM then ok, but I wouldn't go buy a $35 diode to increase system voltage for an AGM battery. An AGM is more tolerant to higher voltages, and does not gas like a wet cell battery, but will charge and be fine on normal voltages.
the sad thing is the diode that is being used in this alternator booster, is like 50 cents. I guess packaging it into a mini blade fuse up's the cost.
Good markup for a 1n4001, eh?