Update and report: First, we finally found someone—Wendy—at Xantrex who took an interest in my problem. It turns out there was an available firmware update that would allow the programming of the bulk voltage down to acceptable levels. Problem? I had to send the unit—already installed—back to Xantrex! No good. But Wendy comes through and says that the Xantrex Combox allows user programming and firmware updates. So I found a good deal at Hodges Marine on a ComBox and got everything hooked up. I’m actually glad I got this because the Combox allows for a wireless router (my son had an unused Apple Airport Express) to be hooked up and I can now with a $39 Android tablet from Walmart monitor all Xantrex devices and reset them from anywhere in the fifth wheel. No more bending over. So we reset everything and all works great now. So let’s go on a trip. We went into the Colorado high country with one of my sons and his family and were six days completely off grid. A good test. We had good Colorado sun most of the time and my three solar panels that total 945 watts had no trouble filling my battery to 24.8 volts. Having the residential fridge and furnace running (every night was near freezing) we would every day drop down to around 21.6 volts. So the average cycle was 24.8 down to 21.6 volts. With anything close to this, which is keeping things between 90 and 40% of my Tesla’s capacity, the battery will last longer than myself or the trailer. Also because there’s no need for ventilating the battery I can have it in my heated basement so I don’t have to worry about the Tesla going to 32 degrees and charging, which would ruin the battery. Another very nice attribute of the Tesla is how fast it charges. Just to try it, I hooked up my Honda 2000 (rejetted for high altitude) and it rapidly charged the battery at a rate of around 40 amps at 24 volts. No more dropping off of amps as it nears full. I can reprogram the battery to be used from 25.2 volts down to 18 volts, giving me much more useable power but to cycle it that far will wear it out much faster. I might only have 700 cycles or so charging at that rate as opposed to probably ten times that doing it the way I am. Anyway, I’m extremely pleased. I’ve shaved 479 lbs off my pin weight, which, for the first time ever, actually puts my Alpenlite below the official rear axle rating of my truck. I took out all four heavy FLA batteries and the Onan generator. So I’m lighter. I can seemingly run forever in the Colorado high country and have a virtually maintenance free battery.
