Converter wiring upgrade.

[Jay2504]

After reading about moving the converter closer to the batteries for less voltage drop, I did a little testing. I ran the batteries down a little then plugged in the unit. Sure enough there was a .55 volt drop between the converter and the batteries. So I upgraded the wiring using what I had. The Ground lead was only about 24" before being screwed into the frame. So I just ran 1 #6 gauge wire from the frame to the converter. (White wire in the pics). On the positive side I had a much longer run so I ran 2 #6 wires from the battery shut off to the converter. (Green wires in the pics) . The result? Ran the same test, only a .28 volt drop. It also doesn't drop off amps as fast. I think I can bring the batteries back with less generator run time. Jay

[Jeff_and_Abby]

Very Nicely Done

"If" that ground / chassis connection is exposed, you could consider some real simple enclosure ... just to a degree of spash protection, doesn't need to be "waterproof" ... do include a drain hole to let moisture out the bottom. Even a sacrificed small food container / tupperware / etc. could work.

[Jay2504]

Thank you. Not a bad idea. The picture doesn't show it but that is on the inside of the frame away from road splash. Another note, on both tests I had a volt meter hooked up at the converter connection inside the camper. The DW watched another (calibrated the same) volt meter at the batteries. About 4 seconds after I switched on the converter my meter went to exactly 13.6 volts and stayed there. Her meter is the one that showed lower voltage. Given long enough the batteries might have gotten to 13.6 like the converter, but I only measured for about 5 minutes for each test. My conclusion: there are some gains to be had by either moving the converter closer to the batteries or running heaver wire like I did. Jay

[Jeff_and_Abby]

Sort of thinking out loud ... as the charge level of the battery increases, we will see the measured voltage at the battery terminals increase of course, AND we will also see the resistance that the battery presents to the converter increase ... Ohm's law tells us that V=IxR so either the current will decrease, likely the case if the converter is delivering a regulated voltage, or the voltage will creep up as you expect if the converter is only current limited or has seletected or "stepped" voltage outputs.

Two #6 wires in parallel effectively yeilds the same current capacity as a #3 conductor (never did get past that quirk in the wire gauge equations) and of course halves the series resistance and reduces the amount of voltage drop. In the end, you should see a real improvement in the amount of time to put a recharge on the battery. I'm guessing perhaps as good as 30% improvement (i.e. 49 hours instead of 70 hours) but that is really a "WAG."

Now ... if it were possible to tweak the voltage coming out of the converter, to account for the voltage drop to the battery ... but at this point we are looking at what, a quarter to maybe half a volt ??? The current limitations of the converter are still more a time issue if the battery is discharged below (charge voltage minus voltage drop.)

Bottom line, think you will see an improvement worthy of your efforts

- Jeff

[Jay2504]

I prefer a "SWAG" lol! Making the recharging time with the converter shorter is what I was going after. I made a mistake when I posted the wire size that I added. The original size is #6 which I kept in place. I added 2 #8 to the stock wire on the positive side and one #6 on the negative side from the converter to the frame. At the front of the frame the negative battery cable is 4/0 to the frame. On the positive side there is 4/0 to the cut off switch, then #4 from the cut off switch to the circuit breaker ( about 2 feet). In cooler weather when boondocking I try to just run the generator long enough to make her coffee. Jay

[Jeff_and_Abby]

"LOL" with 'ya !!!

"Coffee makes EVERYTHING Possible !!!"