High Output alternators?
How common is it to swap the standard alternator out for one with high output, like 140 amp? I would like to hear from someone who has, about what performance improvement you're seeing in terms of how...
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There are two other nuances to this problem. One is that the truck alternator is set up to sense the voltage on your engine start battery, and will cut the voltage back based on it's state of charge. Since it is always nearly 100 percent on a healthy battery, you will typically find the alternator running at 13.5V or so - healthy for it but not the fastest charge for your camper battery. There are no great ways around this - you can upsize the wiring to the camper (#6 wire is sufficient), that will drag the start battery down closer to the camper battery and make the alternator work a little harder. The best way to overcome this is with a 2nd alternator dedicated to the camper, and remote sensing the camper battery's voltage. Not undoable (common on boats) but complicated.
The second nuance is that while the alternator is rated at 135 amps (or whatever) this is the cold rating, a more or less fictitious number. When it is hot - and it will be very shortly if it is producing 135 amps - the output drops to about 60 percent of the cold rating.
In spite of all that, it is the charge acceptance of the lead acid chemistry that still gets in the way the most. Spend your money on solar arrays - cheaper than a fancy alternator, better for your batteries, and works even when the truck is shut off and the camper in storage.
The second nuance is that while the alternator is rated at 135 amps (or whatever) this is the cold rating, a more or less fictitious number. When it is hot - and it will be very shortly if it is producing 135 amps - the output drops to about 60 percent of the cold rating.
In spite of all that, it is the charge acceptance of the lead acid chemistry that still gets in the way the most. Spend your money on solar arrays - cheaper than a fancy alternator, better for your batteries, and works even when the truck is shut off and the camper in storage.
