PD or Iota for my upgrade?

KendallP wrote:
While I am in full support of measurebating ad nauseum... I CANNOT support skipping ANY kind of camping for said. Wait 'til next week.

That's my conclusion. I needed someone to give me a kick.

I can tell you that Sal is correct about the subject at hand.

What is he correct about? Some of his comments seem to imply that a battery load is different from a resistive load. That I find very hard to believe. Some comments indicate the PD has problems with bad AC power. That seems very likely, due to its design and the low power factor of the PD. Some relate to how the PD exits boost mode, etc.

I've seen more than enough graphs by many, fine engineers on these boards over the years to verify his position. And trust me, there are few on these boards that have argued with Sal about the PD with more fervor than I. But on this discussion, I have never disagreed.

After many months of back and forth, I have come to the following conclusion: Given enough resistance, the PD can beat the IOTA to the 90% mark. Properly sized with adequate cabling, the IOTA will likely beat the PD.

With high resistance, especially when the IOTA is oversized for the bank, the PD is the tortoise. The IOTA will quickly reach its trigger voltage and drop out of boost. Then it's a bit of a long road in absorption.

Meanwhile the PD essentially remains in boost and doesn't really drop into absorption until 90%+.

I'm not trying to disagree - just understand. If I put the Iota and the PD side by side, and connect to two identical batteries, how do you think the voltages and currents will compare? Doesn't the Iota use 14.6 for boost? I know the PD uses 14.4.

For techies that prefer manual control, the PD wins.

I'm definitely in the "techie" camp. The manual control and the access to circuit diagrams is what made me select the PD.

For solar guys, a properly sized IOTA with adequate cabling can give you a better morning boost before you let the PV take over.

I'd love to see the charts of two side by side tests. You seem to have decided you know what the results would be. Can you describe what you think would happen - voltage/current/time with such a test? I almost would be willing to buy an Iota just to compare :)

Still... I look forward to your test results.

We'll see what I can come up with. Camping first, however!

For Sal, and others, here is the PD voltage monitoring circuit:



The horizontal bar above R30 is a reference voltage from the UC3846. The connection at the encircled F goes straight to the chip's voltage error amp input. The jumper H4 lets you reduce output for gel cell batteries.