Tigo Maximizers & Module Preparation

Tigo Maximizers

Through some heroic efforts on the part of Tigo Energy, DC Power Systems, and Affordable Solar, I was able to acquire 24 ea. Tigo Module Maximizers (MM-ES060V300W-4RL), 1 ea. Module Management Unit (MU-ESW), 1 ea. wireless transceiver (which communicates with the Maximizers), and some odds and ends.

As mentioned in an earlier post, there is one Maximizer for each solar module.  In fact, the Maximizer attaches to the back of the module.  Its purpose is to balance the DC output of the panel in order to reduce the effect of shading and other module inconsistencies on the whole string of modules.  Without the Maximizer, one shaded panel would seriously degrade the production of the entire string.

The Tigo Maximizer product is brand new and is only now becoming available to the U.S. solar PV market.  Their products will initially be available through two distributors: AEE Solar and DC Power Systems.

Because AEE Solar has a local distributor, I originally attempted to work through them in acquiring this brand new Tigo product.  Unfortunately, they were uninterested.  DC Power Systems, though, were very anxious to help get me the Maximizers in time to meet my deadline (of being on-line by EOY).

I cannot say enough positive about the fine folks at Tigo Energy and, in particular, their new Marketing Manager, James Bickford!  James has tirelessly pushed internally and externally to help me acquire their Maximizers in time.  James has called and emailed numerous times to insure that things were 'in motion' and, once I'd received the product, to make sure any questions or issues I might have were being addressed.

Kudos to Tigo Energy, James Bickford and many others at Tigo Energy, DC Power Systems, and Affordable Solar, a retailer for DC Power Systems.

Module Preparation

Each Tigo Maximizer comes pre-attached to a mounting plate with a clamping assembly along two edges.  The intention is to loosen the clamps, place the maximizer in the corner of the solar module, and tighten the clamps onto the framing of the module.

Unfortunately, the Sanyo modules have a frame edge to which the Maximizer can be clamped only along one edge.  Single-edge clamping is inadequate inasmuch as any vibration at all causes the clamp to loosen.  Our solution was to drill two holes in the frame edge and then directly mount the Maximizer to the Sanyo frame:

 

Of course, it is important to place the Maximizer in one of the corners adjacent to the cable connections of the solar module.

Note that we waited to connect the cables from the module to the Maximizer until just before module installation.  Also, some Maximizers were attached to the left of the panel connection and some to the right.  This was done so that the Maximizer cables could best connect to the next and previous Maximizer in the series according to the following diagram:

Mounting Rail Reprise

For mounting the solar modules onto the roof I used Ironridge Solar Mount rails.  These are heavy-duty aluminum rails with channels into which bolts are inserted for the L-shaped mounts and the module clips, one channel for each:

Ironridge Solar Roof Mount System Rail Cross-section

The channel on the top is used for inserting bolts for:

• solar module mounting clips
• grounding straps straddling joints in the rails
• grounding wire clips for running the grounding wire from rail to rail and to groung

The channel on the side at the bottom is used for attaching to the L-mount which is then lagged into the roof.

Since this is aluminum it is very important to use stainless hardware.  If galvanized (zinc-plated steel) bolts, washers, etc. are used then a galvanic reaction will occur and the aluminum will be weakened.

So far so good.

Attaching the rails to the roof was straightforward:

• locate the trusses
• lay down chalk lines
• pre-drill holes for the lag screws
• goop up the lag screws and the bottom of an L-mount
• screw the L-mount into the truss
• slide the mounting bolts into the lower channel of a rail
• line up mounting bolts with the L-mount and insert
• apply the washer, if required, and attach the nut
• tighten with a torque wrench according to specifications

This part of the mounting was pretty much trouble-free.  Placing the panels was an 'experience'.

Solar Modules & Inverter Arrive

Parts start to arrive!  First in was a palette of panels:

24 Sanyo HIT Power N 210N/HIP-210NKHA5 Solar Modules

Next up, the inverter:

Fronius IG Plus 5.0

And some miscellaneous hardware:

Miscellaneous Hardware

The miscellaneous hardware includes the AC disconnect, fuses, grounding straps, mounting clips, etc.  [The rails had actually arrived after the panels, inverter and miscellaneous hardware, but they were discussed in the previous post.]

All of these components, including the rails, were ordered from Wholesale Solar.  The folks at Wholesale Solar were very helpful and their prices are mostly excellent, but you must know what you want — n00bs are likely to end up with the wrong equipment.

Be careful!  Two examples:

• When asking for my first quote I informed Wholesale Solar that I would have 3 strings of 8 Sanyo modules and "appropriate rails" and explained the arrangement of the modules.  The rails they proposed would work well for an arrangement of 3 rows of 8 modules, but it would not work well for the arrangement I described for them: 1 row of 9 modules, 1 row of 8, and 1 of 7.  
• Their price on the solar modules, inverter and rails were very competitive, but their prices for other components such as fuses, disconnects, and cables were actually higher than MSRP.  Even though I pointed out such discrepancies to them and they promised to check into it there was no adjustment made and I eliminated some of those components in favor of purchasing them locally.

So always check things over carefully, regardless of from whom you may purchase the various pieces parts.

Rail Installation

The rails upon which the solar modules will be mounted were installed this week.  Here is the before:

And here is the after:

The rails are heavy duty aluminum.  L-shaped mounts attach to the roof every 4 feet.  The L-feet are attached to the roof by lag screw driven into a truss.  Sealant is applied to the lag screw and to the bottom of each L.  Altogether, it took about 5 hours to install the rails with two roofers, one rail assemblyman (me), and one 'supervisor'.  (That's a 40° roof!  There was no way I was going to get up there.

The conduit for the DC power leads will run just under the edge of the roof in the soffit.

Panel Optimization Part 3

Last week, while in the San Francisco Bay area, I was able to stop by the Tigo Energy offices in Los Gatos, CA and visit with their very pleasant marketing manager and ask many questions about the Tigo Energy Module Maximizer (EMM)

The EMM is a very simple device which clip on the back of each solar module.  The power leads of the solar module are connected to the EMM.  Separate, and different, leads daisy chain from one EMM to another.  Each EMM has a built-in thermocouple.  The EMM essentially insures that the voltage output from the solar module is kept high enough to prevent series degradation.  Without the EMM, a solar module in shade would develop a high resistance and seriously degrade the entire series of solar modules.

Each maximizer communicates with a central Maximizer Management Unit (MMU).  The MMU can be used to control each EMM (to enable or disable one, for instance).  The MMU also collects:

• the performance and temperature of the solar module attached to each EMM,
• solar radiance information from a separate (optional) pyranometer, and
• AC power generation from the inverter (also optional).

The communications between the EMMs and the MMU can be either wired or wireless.  The wired version uses the DC power lines.  This option requires that the MMU be physically connected to the DC power lines at a point after the individual series of solar modules have been 'combined' into a single DC feed.  This is usually just before the individual series DC feeds enter the inverter.

The wireless version of the MMU and EMMs do not require the MMU to be physically connected to the DC feed, so the MMU can be placed anywhere within a reasonable distance of the solar modules, up to 300 feet (90 meters) away.

In order for the MMU to record the AC power generation of the inverter, the MMU will need to be mounted somewhere between the inverter and the power panel.

Availability is an issue.  Supposedly, 60 EMMs and a number of matching MMUs were to be shipped out to AEE Solar in Redway, CA this week.  I need the following:

• 24 EMMs, wired, 72" power leads, MC4 connections for the solar panels
• 1 MMU, wired, with AC metering
• 1 pyranometer (Licor)

Armed with the exact information I needed to place an order, I contacted AEE Solar's CEO, David Katz.  I'd spoken with Mr. Katz several weeks ago and he had assured me that AEE would help meet my need.  Now that I knew the parts that I needed I passed that information on to Mr. Katz as well as to our local AEE Solar distributor, Orrin Farnsworth.  That was last Monday.  On Wednesday I learned that the 'wired' versions were not being shipped yet so I called and left a message that the 'wireless' version would be fine

I haven't heard back yet!

The solar modules cannot be installed until I have the Tigo components, unless I decide to forego the monitoring, which I am loathe to do.  Nevertheless, if I cannot get cooperation from AEE Solar I may be forced to either go to a competitor (DC Power Systems) or live without the Tigo components.