I'm new to the forum and to electronics in general
I'm trying to use a Nano board to turn a twenty year-old off grid solar power system into a battery priority grid-tied system. But, lest I bore you with the details, I'm hoping to use a two relay module
to turn on AC power to charge a bank of 12v batteries. I have read these two topics:
and to be honest, the information in them, they appear to contradict each other. Or do they?
The relay module has two headers, one three pins and the other 4 pins. The three pins one is labelled 'JDVcc', 'Vcc', and 'Gnd'. The other, 4 pins, says "Gnd", "In1", In2" and "Vcc". The second header I get, Gnd and Vcc need to be connected to -5v and 5v respectively and In1 and In2 will activate the two relays when the corresponding pin is connected to ground (active LOW).
The other header I'm not so sure. JDVcc and Vcc are jumpered together as can be seen in the photo. And Gnd is, obviously, ground. But the device seems to work with only the 4-pin header connected.
OK. I'd be grateful to be corrected if I'm wrong, after all that's what I came here for... I'm surmising that JDVcc would be a connection to an independent 5v power supply and that jumpering it to Vcc means it will get it's power from whatever is connected to Vcc on the 4-pin header.
The module seems to work just fine with only the 4-pin module connected. So the question is;
If I try to use it like that --even for long periods of time-- will I damage either the relay module or my Nano?
And a secondary question: I had planned to use the two modules in parallel to double the current handling of the unit. Can I power both relays from one pin? This is actually not a big deal, I can easily use one pin for each relay, but, for simplicity I have jumpered In1 and In2. Should I undo that?
Anyway, any and all help will be GREATLY appreciated.