Michael Qulek

Aaron Yarbrough wrote:We installed

After looking at the module available now I'm considering just replacing my 320 watt modules with 450 watt bifacial ones. That way I could use my existing racking system and my generation would be 5.4 - 6.5 kW.

In the picture above you can see that the lowest row of modules is still partially shaded at 10:30 am. So, I also was thinking about ditching my inverter, charge controller, and the combiner box for an inverter with a built in charge controller and dual mppt so the performance of the partially shaded panels doesn't drag down the rest of the system. Seems like I could get all of this for $4000 not including the federal tax credit if I install it before the end of the year. Then I could use my still good quality existing components on a project down the road.

Any downsides with taking this route (other than probably convincing myself that I need a new a battery bank as well)?

I would suggest neither replacing you panels, or your inverter/charge controller is a good idea.  You can simply upgrade your system by adding additional strings in another location.

First, before diving in, please explain in detail your inverter and charge controller settings, what the voltage/amperage limits of each?  Those numbers are critical to proper design.  What voltages and amperages are you running through your wiring right now?

I could suggest a couple of things, based on my own personal experience with my own system upgrades.  It looks like you have your panels wired 4S3P, is that correct?  I guestimate that your strings are running at ~150VDC?  Is that correct?  What is the Voc of those panels?  How low are your winter lows?  I would guess the Voc of your strings might exceed 200V around freezing or so?

One easy way to add capacity is through what is referred to as "virtual tracking", that is positioning additional strings of panels in directions other than South.  For my own system, my primary arrays also face South, but I have additional arrays designed to face East, and West.  I say "designed" because they are all on single-pole rotating ground mounts.  You could do exactly the same.  You could place a ground mount facing due East to catch morning sun, or a West-facing mount for the late afternoon.  Besides my 4500W of South-facing panels (but can be rotated), I have 1000W facing East, and another 2000W facing West.  I'm planning on adding another 1000W on to the West-facing array (3000W total) because I typically need a lot more at 5pm, instead of 8am.

It's important that string voltage be within 5% of each other, but amperage may vary from string to string.  That means you do NOT have to have exactly the same panels, just match the voltages.  Any string putting out between 143-157V is going to work just fine.

Another option is you simply add a second charge controller to the system.  You will need to match up the charging parameters so they are exactly the same, and it will work best if you use a brand that is designed to be paralleled and can communicate with each other.  But, with the second controller, you have total freedom as to your string voltages and amperages, independent of your existing strings.

With ground mounts, and string voltages in the 150V range, you can run at least 150' from the charge controller with zero voltage drop.  Right now, I'm running 120VDC for ~130' through 10 gauge copper, and I can't measure any voltage drop at all.

I've seen this myself, shopping at HomeDepot, and placing my hand on a few of their bags of compost.  I could feel the heat in them.  So yes, it works.

Notice though the great size of the the piles, and the diesel-powered equipment used to construct it?  If you live next to a sawmill, you might have access to enough raw material to make it happen?  Homesteaders like me would be hard-pressed to find the cubic yards of material needed to build this?

Sardine salad sandwiches.  Just make Sardine salad just like you would Tuna salad, with mayo, mustard, salt and pepper.  Then spread it onto you favorate bread just like you would Tuna salad.

I checked my own well water with a confirmed LST test for fecal coliforms and E. coli.  The water was completely sterile by that method.

You can also try Lemi Shine.  I add it both to the dishwasher when I run it, and also add a spoon-full to the canner when I'm processing some jars.  One thing that works extremely well on rusted cookware is to sprinkle some Lemi Shine on a steel-wool pad, and clean off the rust with that.

In your case, you might try a sprinkle on a wet green scrubbing pad, and scouring off the film with that?

I did my tilting arrays somewhat differently.  I used single-pole mounts, so that the arrays could be adjusted for both azumuth, and declination.  I can rotate the mounts East to West over the course of the day to maximize output, and I can also adjust the angle of the panels seasonally for summer/winter exposure.  Here are some pics of my arrays, made mostly out of easy to obtain steel unistruts.

Pumpernickle Bread, Boston Baked Beans, Candied Yams,  ect.  I would use it in any recipe calling for molasses.