Tigo Energy Maximizer

Tigo Energy Maximizer

So I've finally got my Tigo system working.  It took a while for Greenspring Energy to get it running.  Part of the issue was that there was a communication issue with 2 (of 6) panels.  This communication issue for some reason meant that TIGO would not generate my login information.  That also confirmed a suspicion I had after I was watching the inverter (before Tigo and TED) only produce ~1.1 kW of power on a beautiful cloudless sunny day.  Once the communication issue was fixed (Greenspring sent over 2 technicians to diagnose and fix) the system was up and running at nearly maximum potential.  And I could finally login to Tigo.

So...why Tigo?  Well, long story short, Tigo was an alternative to microinverters such as Enphase.  It essentially allows each panel to operate individually such that if there was any shading (i.e. trees, squirrels, random cloud) then it would only affect that panel and not the entire string.  My two pics below show how the TIGO is allowing my system to have panels operating at different powers which is maximizing my power output.

Tigo online information (no shading).  System is producing 94.8% of its max potential. 

Tigo online information showing one panel shaded.  Without Tigo, I would have been producing 474W instead of 1,510W

***WARNING***
***NERDY ELECTRICAL ENGINEERING LESSON STARTING NOW***
Why is that?  Well...solar panels are wired in series.  So on one 300W panel, for instance, let's say we have 60 individual solar cells.  Each one of those cells, at optimal conditions would produce 5W such that 60 x 5W = 300W.  Well, because they are wired in series, if one cell becomes partially shaded and only produces 1W, then due to the bottle-neck, ALL the cells will only produce 1W (1W x 60 = 60W).  It doesn't matter if that cells is the first cell or the last cell in the series...then will all be bottle-necked.  And the same goes for hooking up multiple solar panels.  Bummer, huh?

The reason they do this is just the laws of electricity (I know there's a better name, but I don't have time to look it up).  So Power = Voltage x amperage.  Well for the same power, if you hook everything up in parallel, then the voltage remains constant.  Thus as you add more 'power', then the amperage must go up.  Alternatively, if you install everything in series, the amperage stays the same and thus, as power goes up, voltage goes up. 

So why not hook up panels in parallel?  Well...the more amperage you have the larger the wire you need to have.  Ever look in your breaker box?  Check out the varying size of the wires.  The wires that enter the box from your electricity meter are HUGE (200 amps, 240V) compared to those that exit and go to, say, a normal outlet (120V, 15amp).  Well...think about that for each solar panel.  Those wires cannot be 'fished' easily through walls or down conduit.  And those wires are expensive because there's a lot of copper in them.  See the following table (sorry for the headings not lining up with the rows...not sure why it copied that way).  Most likely your house is fed using either and 2/0 or 3/0 AWG cable while a normal circuit in your house is probably a 10 or a 14 AWG.

AWG	Diameter  inches mm			Area [mm2]		Resistance Ohms / 1000 ft		Resistance ** Ohms / km			Max Current ***		Max Frequency for 100% skin depth
0000 (4/0)		0.46	11.684		107		0.049		0.16072	302		125 Hz
000 (3/0)		0.4096	10.40384		85		0.0618		0.202704	239		160 Hz
00 (2/0)		0.3648	9.26592		67.4		0.0779		0.255512	190		200 Hz
0 (1/0)		0.3249	8.25246		53.5		0.0983		0.322424	150		250 Hz
4		0.2043	5.18922		21.2		0.2485		0.81508	60		650 Hz
6		0.162	4.1148		13.3		0.3951		1.295928	37		1100 Hz
8		0.1285	3.2639		8.37		0.6282		2.060496	24		1650 Hz
10		0.1019	2.58826		5.26		0.9989		3.276392	15		2600 Hz
14		0.0641	1.62814		2.08		2.525		8.282	5.9		6700 Hz

Well a 10 AWG wire might be $1/ft at Lowes while a 2/0 AWG wire is $6.50/ft.  That's a big cost difference if you have to run a wire 100-ft to get from the roof to your breaker box.  And at 0.50" DIA try bending that 2/0 wire to get around a corner. 

Just doing the math, using the pic above where the panels were producing 1.86 kW, that's roughly 310W/panel or 52V @ 6amp.  Running in series, that's a 6amps and 310V using a 10 AWG wire.  Running in parallel that's 52V @ 36 amps which would require a 4 AWG wire.

OK...enough of the electrical engineering lesson.  Hopefully it was semi-informative even though it was basic.