PD or Iota for my upgrade?

Salvo wrote:
We'll be anxiously waiting for those test plots.

Here we go:


The test results were done with the generator supplying AC power. Both cases (mod and not mod) were done with the same 50% DOD. I lowered the gen voltage before starting the test to 119VAC unloaded. I normally run closer to 126 VAC unloaded. It dropped to 117VAC immediately on loading. It wasn't always a constant voltage. I saw the gen drop to about 113VAC.

When the output reached about 14.0 volts I wondered how low I could drop the input voltage and still get 80A. As long as the input ACV was at or above 113VAC it would hold 80A at 14VDC output. I did a similar test at 13.6 where it's specced. It met its specs of 80A at 13.6 volts as long as the input was at or above 111VAC. You can see me playing with the input voltage after an hour of charging - the output current held steady as I lowered the gen voltage, then I'd reach a limit and it would start to drop. I used various methods to change the gen voltage - loading it up with another AC load would drop the voltage, or I could adjust the throttle.

So to summarize, this test (the mod numbers) was done with the AC voltage from my Onan 4.0CCK ranging from 117VAC to 113VAC and it had my 3 mods - the target for boost was 14.8, the current limit was lowered from 80A to 60A and the current sensor was lowered to counteract the current limit change so 80A looked like 60A.

Note that the not modified numbers show the boost mode dropped off at 4.05 hours. That's an artifact. It really dropped off at 4:00 hours, so you need to scale that axis - sorry, I didn't have time to fix it, so the time comparison is slightly off. The voltage and current can be directly compared, with a slight change of a few percent for time. The mod numbers also drop a bit before 4:00 hours, again, that's an artifact (it has to do with the rate data wa being spit out by the monitoring system from the TriMetric).

The "not-mod" numbers are the same as the original chart I posted. I considered using a better connection to the PoCo instead of the gen for my power testing, but I wanted to know exactly what was going to happen when I was dry camping.

Yes, I see the odd climbing 80A to 84A, and no, I don't know exactly why that's happening. It may be caused by the gen.

I also see the slow decay to 75A. You can also see that the slope is steeper during the rapid decay after it reaches 14.7 than it was before the mod. I think that's the main effect of the mod of the current gain error amp I did. I wish I had more time to do more tests, but that's probably the end for quite a while. I'm extremely happy with how fast it's doing a 50% capacity recharge on the Onan.

I no longer think it's worth doing remote voltage monitoring 0 the voltage over the cables is always less than .1 volts, probably less than 0.05 volts. It would be worth it to do temp compensation. Adding the third cap is also in my plans. Playing with the dead time would be fun, but performance is now good enough that I'm at the point of diminishing returns.