Higher capacity (current output) alternator in itself is a non-issue, it is why car folks install one that can be the problem.
If the stock electricals are properly designed and all connections are good, everything should be fine and happy as delivered and have no problems..
Now, motivated car owner wants to add more powerful head lights, a set of fog/driving lights, really powerful electronic ignition system, big audio system and every other techno-electrical do-dadds in the car.. then there could be problems. In the case of the X..
The stock ignition switch and all related connections carry most of the current when the ignition is in the "run" position. Example, this switch is designed for 30 Amps.. Now, with all the techno-do-dadds added to the switched circuit, without proper relays, the ignition will now suffer trying to carry say 60 Amps. At it's rated 30 Amps, the switch contact resistance or loss at 30A as an example is 1 Amp or 12 watts (this is EXTREME and not typical unless something is very wrong with the switch, typically any more than 0.1% loss is excessive), Now with 60 Amps under load the switch losses grow to say 2 Amps and becomes a nice heater cooking way the insulation and as the temperature grows, so do the losses. In no time flat, we have a nice charred switch and possible related connections.
Our higher capacity alternator is happily putting out that extra power asked of it with the help of the battery.
Keep in mind that battery is able to put our several hundred amps of current in nothing flat. Or basically an arc welder in a box.
If the uprated alternator is a 4 wire modern deal, it will have a sense wire which is used to provide feed back to the alternator asking it to maintain set voltage regardless of the losses between the alternator and sense point (if properly installed). This further cooks the switch as the alternator will produce more power to compensate for the losses in the suffering ignitions switch.
The VAST majority of problems in electrical systems are due to poor connections. From bad to old corroded crimps to corroded connections, bad wire (corrosive liquids wicking up into the wire due to capillary action), loose connectors, corroded fuse connections, solder connections that have been exposed to high temperatures and caused the solder connection to re-crystallize resulting in no connection and more..
So, a higher capacity alternator is not a problem solver if the rest of the electrical system is in desperate need of attention and repair.
Me, I have plans for adding electrical widgets, which is one of the reasons that 80Amp Denso went in. The wiring also got upraded knowing the rest of the electrical system will need to handle the added power requirements.
Bernice
Im not sure I understand this. Please explain.
Originally Posted by
Rupunzell 
Oh, if one does increase the alternator capacity due to higher power lighting or etc.. and does not consider where this extra current goes, there will be problems..big problems.
Bernice
