Friday, January 19, 2018

Keeping it Neat: Off-grid Samlex Inverter Installation w/ E-Panel

Chuck finalizing the installation of six SolarWorld 300W solar PV modules.  The Samlex EVO4024 and battery bank are housed inside this nice pre-built shed.

Samlex wasn't even on my radar until I got a call late last summer from a couple who had purchased a Samlex EVO4024 inverter for their off-grid home near Belington, WV.  Up to that point I had mostly used Outback and Schneider/Xantrex brand equipment for off-grid jobs.  Chuck and Deb who had this Samlex unit had also purchased a bank of Trojan batteries and a Generac 15kW EcoGen generator.  When they called they were in search of someone who could pull all the pieces together into a functioning off-grid electrical system.
Part of pulling the pieces together was the addition of a MidNite Solar E-Panel.  Not to get too technical about things, but I find it's common for folks who source their own equipment to overlook key switch gear and enclosures that ultimately make a system safe, serviceable and code compliant.
Looking at the EVO4024 for the first time I was cognizant that the unit, as it is sold, could not alone yield a polished final installation.  Basically, it was lacking a cover for the large DC cables that connect the inverter back to the batteries.  This is fairly common among inverter manufactures, but does not yield a safe or code compliant installation (it also leaves things looking sloppy).
Many off-grid inverter manufacturers offer units without any enclosure to protect the DC cabling.  Most, however, do offer an optional enclosure that can be purchased separately and is purpose built to be paired with their inverter equipment.  These optional enclosures commonly include space for disconnects and breakers that protect the wires and the electronics in the system.  Samlex does not offer something like this and I was a little perplexed after I first gave their website a once over and concluded that I would have to look elsewhere.

The big dark blue box is the EVO4024 inverter.  It is mounted to the E-Panel which is affixed to the wall.  The MidNite E-Panel includes the gray portion below the inverter (this limits access to those DC cables).  The small black "thermostat" at the right is the control panel for the inverter.  The larger black piece of electronics is an Outback FM80 solar charge controller.

MidNite Solar would win an award as the most creative manufacturer of solar related enclosures and electronics equipment.  They were the next place I looked for an enclosure that could be paired with the EVO4024 inverter and sure enough they had something tailor-made to fit!  MidNite Solar has been manufacturing E-Panels for maybe almost ten years - I can't remember for sure.  These E-Panels were created as a way to minimize the footprint of an inverter installation as well as the cost.  I don't always use E-Panels because the wiring space can get tight, but they certainly have their place and they are the only game in town if you want to make a Samlex EVO4024 installation safe and sharp looking.

This series of photos is probably a better illustration of how the E-Panel consolidates the AC and DC wiring as well as the associated breakers.  Note the big red breaker guard for the main DC cables on the left side of the E-Panel.

My experience with the Samlex EVO4024 was great.  The unit has a very nice relay that allows it to trigger the EcoGen generator to fire up automatically without the addition of any other electronics  Another plus for Samlex is the comparatively low cost of the system control panel.  The cost of inverter control panels has become a major hang-up of mine.  Some control panels cost more than $400!  That's a chunk of change for something that really resembles a beefed up thermostat.  Anyway, the controller for the EVO4024 costs less than $200.  It's probably the cheapest controller out there.  Finally, and most importantly, the technical support from Samlex was the best I have had from any inverter manufacturer.  By "best" I mean that there was no time wasted on hold and the support staff gave me the impression of being upper-tier right off the bat.  The technician who I spoke with was knowledgeable, polite and I got my questions answered while I was in the field.  I called multiple times and there was no deviation from this stellar service.

Monday, January 15, 2018

Winter Sun | High Voltage

Well it's January 15 and you can already tell that the days are getting longer.  The cold temps have conspired with a few really beautiful sunny days to make for some good peak PV power production.  Those bluebird days where the snow reflects the sun and the temps stay well below freezing are some of the best days for solar.

People are often surprised to learn that colder temps really enhance the output from a solar PV system.  In fact, cold temps are a primary consideration when designing a system.  The voltage from a solar PV panel can increase 14% or more as the temperature decreases.  If you fail to account for this during the design of the system you may goose the charge control or inverter equipment with a voltage that exceeds the operating limits.  Yikes!

It being winter, I like to roll out my mother-in-law's favorite ski video.  So far, this winter has already bested the last two for quality skiing days.  Hope there are many yet to come this season.