PD or Iota for my upgrade?

Salvo wrote:
I don't believe these mods will keep the PD in constant current during boost mode. The main complaint of the PD is that it tapers current right after turn-on. A 60A PD can't charge at 60A.

You can review the performance tests from the graphs posted in this thread. It increases current to about 84A when initially turned on from 50% SOC over the first 1-1.5 hours, when powered with my generator at 113 VAC, then falls over the next 1-1.5 hours to 75A. I didn't do this test with mods when powered from my 105 VAC shore power line. I did do it without mods on 105 VAC shore power - results also posted - and it shows a taper. It isn't clear to me if the performance difference is solely due to AC differences or the mods plus AC.

However, WoodIsGood is looking to decrease current output, so this issue shouldn't affect him.

I would be very interested in any testing by others. I have the stuff needed to do testing, just not the time (plus the batteries are out for the winter).

I'm not convinced that the PD does initial tapering, even unmodified, if the voltage is at least 113 VAC, although I agree that higher voltage is better and there is tapering at 105 VAC, unmodified, as shown in my own testing. The only other testing I've seen that I'm convinced was done correctly used a straight resistive load, and measured the output. That is the best way to measure the effect of different AC voltages at input. That testing showed little or no tapering IIRC.

I suggest for those who want to make the mods, first document PD performance before making changes. Discharge batteries to 50% SOC (about 12.1V). Turn on PD and measure charging current and battery & converter voltage. For the first 5 min, take measurements every minute. The following 10 min, take measurements every 2 min. Then measure every 15 min. You can also assemble all meters in one location and take a video of the charge profile. Run the same test after making any mods.

I agree. I had two purposes in making the mods. The first was to control the boost voltage. That mod works perfectly. I may eventually add in automatic temperature compensation, but right now my manual output voltage control is enough.

The second was to deal with the perceived issue of current tapering that some posts spoke about. At 105 VAC I saw that issue myself. That is the voltage of my shore power extension cord when feeding the PD9280 at full throttle. Unfortunately, I didn't test at 113 VAC or my normal generator operating voltage of above 120 VAC.

I don't know if the mods had any effect on the current tapering issue, or if it was solely an AC voltage issue. Since I don't see it when charging with my gen, and don't care about fast charging if I have shore power connected, I haven't done the final testing needed to resolve the issue.

There have also been comments that the PD series has trouble with AC produced by inverter-type generators. I have no personal information about that, beyond what is posted above. I'd like to see proper testing of that issue as well, but since I don't have an inverter gen, I can't do such testing. I will eventually do AC voltage testing eventually, just to resolve that issue in my own mind.

I'd be very interested in any testing done by others.