Small PV Data Logging

Hi Jonathan;

I use a Morningstar Relay Driver, which is actually 4-voltage controlled switches.  I could have gotten by cheaper, but I wanted to be able to expand later.  The relay driver costs about $150.00.

The relay is nothing special.  For ease of hookup, choose one that has a coil rating that is the same as your battery bank, 12 volts dc for example.  You could even use a solid state relay if you so choose.  I use the relay contacts to turn on/off my inverter, so the relay doesn't need to pass a large amount of current.  In other words, the off/on relay does not pass the potentially high dc input current of the inverter.  (I hope you understand what I'm trying to say).

The automatic transfer switch is made by Iota.  It's rated at 30 amps, and it set me back about $55.00.  Actually, it's nothing more than a relay. 

My inverter has remote on/off capabilities, or in other words, a terminal block.  This terminal block allows me to wire in a remote on/off switch, or in my case, the relay contacts.

The lascar data loggers are programmed via a PC, and use the time/date information from the PC.  If you're setting up two of the lascar data loggers from the same PC, the time/date information for both of them should be farly close.  You'll set the sample intervals, (1 minute, 5 minutes, 30 minutes, etc.), and they should be fairly closely synchronized.  There is no way that I know of to actually connect the two data loggers together for exact synchronization, and there are no buttons or switches on the data loggers. 

John