PD or Iota for my upgrade?
I'm thinking about a converter and battery upgrade. The batteries will be wet cell lead acid 6 volt Possible T-105s or the 230AH, EGC2 from Sam's club. I'll probably go for four. (Does nayone have...
Forum Discussion
Salvo wrote:
Nothing strange is happening to the cable, battery or meter. It's the converter!!!
If those are true DC voltages and currents, I just don't see how it can be the converter. If you apply a high enough DC voltage to a battery, DC current will flow into the battery. That's just basic electronics. It doesn't matter what converter is providing the voltage. There's no way for the converter to limit DC current without lowering DC voltage applied to the battery. If you have two identical batteries and connect two different converter/chargers to them, you'll get the same current flow into the batteries if the converters are holding the same voltage.
I'm not disputing that the tests were made in good faith and reported accurately. I'm wondering what assumption we're making that isn't true. Clearly the converter can supply at least 44A. It does that at around 13.5 volts in the chart. Clearly it can supply more voltage than that, the voltage rises over time. So I'm wondering if I'm seeing something other than DC currents and voltages. There are certain overvoltage, overcurrent and overtemp limits on the output, but the effect of all of those should be to lower the output voltage to lower the output current.
The sudden dropoff of current from 44A to 23A looks like the converter changing modes, but the way the PD converter works (and all the others I've looked at) is that each mode has a different output voltage. That's the way the converter controls output current. It's the only way it can control output current. But the chart doesn't show any sudden voltage change associated with the sudden current change.
To me that either means we aren't measuring current and voltage correctly, or the battery load is changing. If it's the latter, we'd see the same performance for all converters. I'd love to do the test suggested by Wayne, which would answer that, but I've only got the PD9280.
Still, this is bugging me enough to make it worthwhile to do some testing for my own peace of mind. I finished most of my TriMetric installation last night, and if I can convince my wife to skip the weekly camping trip in the RV, I'll see if I can get some baseline numbers on my PD to see if they look at all like those charts.
