mirceaalex001 wrote: ↑
Thu, 17 May 2018, 14:23
And measured with a multimeter , even with the pv switch off , i have that 46v there ,
By "there", do you mean at the PV input terminals? Is it possible that this is leakage across your PV switch? For example, can you ever see this 46 V at night?
so , somehow is taking dc current from another place .
It must be taking *some* current to see the 46 V at the PV input, but even 5 microamps would be enough to register 46 V on a multimeter with a typical 10 MΩ input resistance. But I think that you're saying that the SCC relay coils (there are two in parallel) are turned on somehow. That would require of the order of a watt, which is some 20 mA at 50 V, and would require more than that (a few watts) to drive the SCC processor and associated electronics as well. But I can't imagine the current draw from the battery being near the 28 W that has been mentioned, just for the SCC electronics.
I have found another way to turn it off ( the panels ) is by setting the max charge to 0 [ amps ] and then back to desired amp . After it disconnect that relay , is ok , until is connected again, so is like is some dc voltage on the other side of the relay , or is like a circuit that closes with that relay . Do You have any ideas what can be ? Or if i can set the pv input voltage cutoff .... ?Thank you !
It sounds like what is happening is that somehow some of these SCCs are drawing power from the main battery even when the PV input is not present. They are designed to take their power (for the electronics) from the PV input only. However, I could imagine some errant path whereby the battery could supply power to the electronics, keeping the output relays on. The relays are
between the SCC output and the main battery. That would cause a small drain from the main battery, which would go away when the SCC is told to turn off its relays; it sounds like setting the maximum charge current to zero amps does this.
Since the SCC stays off after forcing the relay off once, it suggests that the SCC isn't getting power from the PV input. But it's not certain, because relays require a lot more voltage (and hence power) to pull in than to hold their held-in position. If you have leakage across your PV switch, it might be enough power to hold the relays in, but not enough to pull them in once off.
You could prove that one way or the other by disconnecting one or both wires to the PV input; if there is no significant leakage across your PV switch, this should make no difference. Do this at the end of a day before forcing off the relays, of course.
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