Quote:
Originally Posted by Bill
Good point. In one of our earlier TMs, I ran new, uninterrupted lengths of #10 wire from the alternator to the truck's 7-pin Bargman connector, and then from the TM half of the Bargman directly to the TM battery post. As I recall, #8 wire would not fit into the truck's Bargman connector, but #10 could be squeezed in. It helped quite a bit, though it was not a perfect solution.
I'm not sure when the truck's alternator would be putting out 14.8 VDC for any length of time. The alternator output voltage will be determined by the voltage of the truck battery. When you start the engine, the alternator may go to some high voltage for a few seconds to replace the charge used by engine starting, but then will settle back to the truck's proper float voltage, which will be around 13.8 VDC
This lower voltage makes your big-wire solution even more important, or course.
Bill
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Correct on all points and more to the point...... yes, when the alternator is putting out 13.8V the voltage drop is 1.2V (I measured it before and after my mod). After I installed the larger wire the voltage drop was less than 0.2V
If one was to use the larger wire size, the alternator/regulator would pick up the 'Line voltage". It doesn't know where that voltage is coming from. If the TM batteries are in a constant discharge mode from the 12V fridge circuit, that would reduce the line voltage and increase the charge rate from the alternator enough to keep both batteries fully charged.
I know this because I've done it (before I added solar) and it was quite successful on a 10-hour drive from Los Angeles to San Francisco area. I arrived with a cold fridge and fully charged TM batteries.