Bypass / Blocking Diodes

Snowman9000 wrote:
OP are you sure your panels don't have blocking diodes? That would be unusual today, I think. If you don't, then maybe the voltage mismatch is creating the anomaly. Seems like without blocking diodes, your higher voltage ground panels could send current to your roof panels, depending on conditions.

That is exactly what I wondered about & why I asked about blocking diodes.

The only diodes in the connection boxes are in parallel with the panel, i.e. Bypass diodes. A blocking diode should be in series with the output - there isn't one on any of the panels.

As to the voltage - the output of the controller when in the float stage is at 13.6, and doesn't change when plugging or unplugging the portable panel. After the sun goes low enough to drop the input voltage below float, plugging the portable in does increase both the output current & voltage.

I'd understand if it went up or stayed the same, but don't that it goes down.

Again, I stated in the original post, I don't think it is a problem, I just want to understand why adding the portable panel decreased the charging current when the controller was in the float stage. I suspect the controller is causing it, but don't understand why.