4 days of clouds in a row... we slowly ratchet down on the batteries. They're gunna take a hit today because we are going to can some tomatoes. Holy smokes, imagine me having to buy power in the /summer/....

Just something of note... the guy with 13kw of MPPT chargers and 26kw of panels is often done charging for hte day by noon and then his system makes only the power he's using moment to moment for the remainder of daylight hours.

Note that with 13kw of battery chargers, he's still able to make 77kwh in a day... more than the 50kwh that the average house uses.

Over panelling allows you to make predictable power even when it's cloudy.

I fielded a call from a group member the other day, he said he noticed arcing between two panels mounted in his ground mount array. As it happened, he had dropped a 2x4 on a panel and cracked the glass sometime ago. In the past several months it got water inside and developed what we call a ground fault.

Ground fault occurs when the internals of a solar panel which are normally insulated from the metal frame end up touching the metal frame. Usually this is from water ingress. The result is that the aluminum frame is now "hot" with a few hundred volts on it. Now imagine your child playing in the back yard and touching the frame of the panel.

In his case he had mounted two rows of panels to two rows of unistrut and one malfunctioning panel had made every panel on that row hot.... and it was arcing between panels on the other row. The votlage of the arc was about 130vdc our of a 260v array.

Two things came of this... he had never gone back and grounded the frames of all panels together nor had he driven a ground rod. The idea here is that we want the frame of the panel to be at the same voltage as the earth around it. If the difference in voltage between where you stand and the frame of the panel is 0v, you can't get shocked. Ground bond all panels, all metal mounting rails and a ground rod driven into the earth together.

Secondly, another issue came to light. His combiner box took the negative leads from every string of panels he had and connected them to a bus bar. Only the positive from each string of panels was run thru a fuse. When his ground fault occurred, disconnecting the positive wire's fuse didn't stop the arcing because the negative wire from the panels still gave a common connection.

Fused combiner boxes are always needed when combining 3 or more strings together, but every commercially available one I've seen only fuses the positive lead of the panels. This is an oversight. You should use two pole DC rated breakers or two fuses when combining strings of panels.

Remember folks, it's not enough that something works... what is important is how it works with something is wrong.

More about ground bonding.... you can certainly install a ground lug onto your panels and then connect them with a bare copper ground, of you can use a proper solar panel clamp. Shown here is the IronRidge UFO mount. Look carefully and you'll see several little spikes on the washer under it. Thse will cut thru the anodizing on the solar panel frame and provide the necessary ground bond to the mounting rails. Then you only need to ground bond the rails.

Maybe this will come out sounding bad.... but....

The difference between an amateur and professional craftsman is that the professional knows how to fix his mistakes.

Similarly, the difference between a handyman and an engineer is that the handyman makes something that works and engineer designs around the potential failures.

Here’s a video that takes 16 minutes to tell you how to calculate the size of a house battery in 5 minutes.

Ha!

Today after it stopped raining and the sun came out, we laid out batten boards around the perimeter of what will be the pole barn and got the 4 boundary strings all square. After about 4 attempts moving the strings, I got her square within 1/4" on the diagonals.

FWIW, I logged into the NOAA sun calculator and found that at 9:42am the sun would be directly east of me. So at 9:42 I noted the shadow of the pole the meter base is mounted to and marked it. We used that to draw a dead level east/west line. Now the roof of the building will be facing exactly south.

https://gml.noaa.gov/grad/solcalc/

Let's play a game. The grid gets shut off for 3 days. What happens to your fridge? You better start eating perishable foods. What happens to your freezer?

Next... what happens when the lights come back on? Everyone will run out to the grocery store. Will there be enough food at the grocery store? Did they have a back up generator? Will there be a riot? Will people have their shopping carts stolen as they walk to their cars?

All it takes is the power to be out 3 days.

foodshelterwater
Never forget that 33 years ago we learned the government will kill your dog, shoot your 14 year old son in the back and snipe your wife in the doorway while she holds your infant child.
#RubyRidge

Imagine being 14 years old, living off the grid in the Idaho woods in 1992. You’re walking your dog when suddenly he growls and *bang*, the dog is shot and killed. You look up and see a man in a Ghillie suit with a rifle pointed at you. Fear grips you. You pull your gun and fire. You’re just defending yourself. This is your home.

You run back toward your parents, only to be shot in the back and killed before you can reach them. You never understand what went wrong or why.
The next day, a sniper fires again. Your mother, standing in the doorway holding your baby sister, is hit in the head and killed instantly.
All of this started because your father Randy Weaver, sold two sawed-off shotguns to an undercover agent and refused to become a government informant.

They gave him a false court date and set up armed surveillance at your home, waiting for the moment they could escalate.

Randy Weaver was a former U.S. Army Green Beret. He served in the military before moving off the grid with his family in northern Idaho. His military background added to the tension for federal authorities, because he was trained in weapons and survival, but it didn’t make him violent or a threat to anyone outside his property.
After an 11 day stand off with Randy and the baby inside with two dead bodies, the government was ordered to pay millions in settlements to Randy.

Meshcore / LORA experiment today. 47km from my house to a drone flying a repeater. My house antenna is 85ft above terrain, and the drone worked at 150-120ft up but not at 110ft.

According to the math, it should not have worked yet it did. There's terrain way inside the fresnel zone

For the non-radio people, 160mw (a little more than 1/8th of a watt had reliable communications for 30 miles. For comparison, most FRS radios are 2watts and "supposedly" go 5 miles but never do.