November 25, 2019

Burying the Solar Cable

Last time, I showed you how Dan wired the solar panels. The next step was running the cables which will connect the panels to the charge controller (which will connect to the batteries). For that we needed multi-stranded copper wire cables with solar connectors on the ends. We needed two, one for positive and one for negative.

Solar cables. More at Amazon.

Before I could buy them, I needed to know the correct size. Size depends on panel array voltage, amperage, distance from the batteries, and acceptable voltage loss (typically 3-5%). I ran our numbers through several online calculators and the results were all the same – size 12 American Wire Gauge (AWG).  Even so, larger cable would further minimize power loss, so I bought 10 AWG, which is the next larger size. If we had to go a farther distance, we would have used 8 AWG.

The cable comes in pairs, one black and one red. Since the connectors are already attached, it was just a matter of burying them. Of course, Dan had help.

Snoopervisor Meowy bossing the job.

It's a span of about 30 feet, but the ground was moist for easy digging.

Electrical codes dictate whether and how different types of cable can be buried. Ours is rated for either direct burial or in a conduit or raceway. Dan used PVC pipe because that's what he had.

Two 90-degree elbows finished it on the panel end.

Ready to plug in after all the parts are in place.

It goes under the driveway . . .

Checking trench width and depth.

. . . to where the battery box will be.

Battery box will go here, allowing enough room
to open the little crawlspace door on the right.

This will be a good spot for the batteries. It's outside, which is important for battery off-gassing. It's accessible, making it convenient for battery inspection and maintenance. It's close to where the freezer will be, which is on the back porch above the crawlspace door. It's shaded all day, which will help keep the batteries cooler in hot weather. In summer, Dan puts a vent fan in the crawlspace door, which means we can blow the crawlspace-cooled air across the batteries. That's very good considering how hot our summers can be. An added bonus is that we'll finally get that ugly last patch of the old exterior siding replaced! Yay! (This must have been what we were waiting for, lol.)

The next step is getting the batteries and building the box.

Burying the Solar Cable © November 2019


wyomingheart said...

Great post, Leigh! Do you know how many batteries you will be needing? I saw a project on line where they used two (used )fork lift batteries, and it has peaked my interest in them. According to the author, that was all they needed to run lights and fridge during the winter. I love to learn new things, and having you first hand show us how is priceless! And of course, no project would be complete without proper feline !

Leigh said...

Wyomingheart, thanks! There are formulas for figuring out how many batteries, based on the number of days of reserve energy one wants and the size (in amp-hours) of the batteries. In my original post on this series ("Solar Pantry Part 1: Feasibility") those formulas told me I'd need anywhere between 8 to 12 batteries for three days, depending on their amp-hours. I almost gave up after that, because that was way out of budget. But I finally decided that something was better than nothing, so we've settled for fewer batteries and fewer days reserve. I figure even one day more during a power outage is more than I'd get on grid!

The other thing about battery size is weight. Golf cart batteries, for example, weigh roughly 65 pounds each. Fork lift batteries, on the other hand, weigh 800 pounds and up! So the question (besides cost) is the ability to handle them. :)

There's no one-size-fits-all solution, so each of us ends up having to figure it out for our particular needs and budget. But that's why it's interesting to read how other's have approached it, what they decided, and why.

Ed said...

I'm following and taking notes.

Hill Top Post said...

This is something all of us should be taking notes on. It will be an exciting day when you generate your first electrical power.

Rain said...

I'm taking notes too! Great job on the digging Ms. Meowy! ;) Oh and Dan too lol!

Leigh said...

Ed, if anything, I hope these posts make it seem doable!

Mary, very exciting indeed! It will be a wish come true. :)

Rain, Meowy is always such a good help. Especially when it comes to taking breaks. Every now and then she demands Dan or I take a break to pet her. She's very insistent on this point!

Toirdhealbheach Beucail said...

Battery placement was a concern. I will be interested to see the final set up.

Leigh said...

TB, we were wondering about that for awhile too. :) We discussed putting them in the crawlspace, but ours is fairly low so not convenient for monitoring batteries. Another spot was around the corner, but it was too sunny, we thought, and likely too hot in summer. Dan came up with the location we finally chose. Perfect!

Mama Pea said...

Our batteries are on a north wall in the heated part of the garage. Of course, our location is so different than yours in that we're more concerned with the months of below freezing temps (outside) than we are about heat in our more tempered months.

Right now we're in the part of the year where we don't get much sunshine on, or power from (!), the solar panels. November is traditionally a gray, sunless month for us but as we get into December and January we'll have more sunlight fueling the panels and batteries!

Su Ba said...

You're getting close that exciting day when you switch the freezer over to solar. When we did it, hubby was like a nervousness hen, checking the meter readings multiple times a days, for weeks. But all went well.

Leigh said...

Mama Pea, our winters can be iffy for sun, so I'm glad we'll be getting this up and going during that season. It will give us an idea of our "worst case" production. Dan wants to insulate the battery box for our coldest days and nights. I'm thinking I should put in a digital thermometer than records highs and lows, because our excessive temps will be a problem too.

Su Ba, I already feel like a nervous mother hen! LOL. After looking through the charge controller manual, just learning how to read the read-out will be a huge accomplishment.

Renee Nefe said...

I had to show my hubby your snoopervisor. He was impressed, with the solar set up as well. Funny we were just discussing the possibility of putting in a Geo-thermal system to heat our driveway...pricy but would pay off in not having to hire someone to shovel our snow when we are too frail to do it anymore...which feels likely closer every snowfall.

Leigh said...

Renee, what an interesting idea! I can see how it would be well worth it for you all I know I'm glad we worked to have less work as we got older. I'm sure your snoopervisor would approve. :)

Cockeyed Jo said...

Good post Leigh. Burying the cables is a very good idea. We plan to also.

Leigh said...

Thanks Jo! We considered running them on a pole for about half a second, but burying them seemed the best way.

Helberg Farm Stories said...

Thank you once again for such great understandable insight!! Nice job and thank you for sharing it all.

Leigh said...

Always glad to share. :)