TalkBaja.com » Baja Mexico Forums » Off-Grid / Solar, Wind or Generator?

Originally Posted by BajaGringo

That inverter goes on eBay for something like 1200. So far it has worked flawlessly. How do you have your system set up for lightning protection Larry?

I am certainly not an expert on lightning protection, I just put as many ground rods in as I could afford. The ground is so rocky where I am at that it is nearly impossible to to get a rod any more than a few feet into the ground. My solar array is on a pole that is 4' into the ground, my generator is bolted to concrete and has a ground strap to earth. My inverters and elec. panels are also grounded to earth. I don't have any lightning rods or anything like that.
Larry

Years ago, used to work in Line Construction.. putting in transmission towers, and substations..

Substations.. we would use a trencher and put a grid across the entire site about 2' deep..

We would have rolls of No. 4/0 AWG bare, stranded copper delivered which we would put on dollies.. and the entire grid was tired together with "Burndy connectors" which were installed with a hydraulic press ... plus very large copper rods sunk into the ground at various locations..

Towers had lighting arrestors which were also tied into the grid..

Then we would start pouring footing for the "switches" and the large transformers and other parts of the substation..

That was a Betchel job I would on in 1968 and which one can still see from the Antelope Freeways 14 just as you reach the turn off to Pearblossom and the Angles Crest Hwy..

Really tuff stuff, we blasted.. plus using old fashion jack hammers with really long extensions..

Your talking about hard ground.. caused me to think... boy it was tough going on some jobs... wow

So you are running different grounds for each device/system? I read on one site where I guy recommends setting up five lightning rods around the extreme limits of your property in a star pattern as much as your lot layout allows. He noted that it was a geometric/statistical advantage in that format that would greatly increase your odds of drawing a strike away from your home/gear. He also recommended running heavy welding cable down the lightning pole to the ground as the fine stranded welding cable is more "attractive" to lightning than solid or standard braided. Rocky ground is a problem for getting a ground rod deep enough. All I can think of is just dig and bust rock, dig and bust rock. That or get a real long masonry drill bit?

Wooo asked about the trick for installing ground rods and I forgot to post it. The method is real simple:

1) Choose your location for your ground rod and dig a hole about a foot deep, tapering the sides down towards the center.
2) Fill the hole with seawater and continue to refill it as it drains, over several hours.
3. File grind a point onto one end of an 8' grounding rod and begin working it in by hand.
4. Continue to add seawater to the hole as the rod goes down.
5. Hammer in the last few feet if needed.
6. Add a few more buckets of seawater to the hole.
7. Clamp the grounding nut below the surface to the grounding wire and cover.

The author of this method likes using seawater as the high salinity/TDS makes the ground around the rod much more conductive. I tried his method and my grounding water went in quite easily.

YMMV

Thanks for the info, RPLarry and NoProblemo!

How much you spend on batteries (after you have sized them for your energy needs / system) will also vary based on whether you decide to go with flooded, glass mats or gels as well as brand...

OK, so our wind turbine is up and operating. It is giving us 1.5 to 3 kW per day ranging from low wind days to high. The most important part is that it is giving us amps feeding our battery bank after the solar panels stop producing. I hooked up our Whirlpool 12 ft3 fridge and it has been running 24 hours a day without a hitch. Our battery bank has never gone below 25v with the fridge running, and that includes a couple of very foggy days where we saw almost zero sun.

Attached are photos of the wind turbine and the control panel (still a work in progress) inside...

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Just curious, for those of you off-grid - what is the "normal" voltage you see on your battery bank in the early morning on an average day before your panels "wake up"???

Originally Posted by BajaGringo

Attached are photos of the wind turbine and the control panel (still a work in progress) inside....

BG: I see that your avatar and then I see your control panel and how neat and well organized it is -- and I see a total opposite reaction.. its like your control panel should be a rats nest of unorganized wires and batteries and leaking battery acid and such..

I think I put too much into the avatar being an actual picture of you I suppose ..

Beautiful work on your electrical room though!

I thought the same thing when I saw that photo... C.L.E.A.N. install!

That avatar is some hippie's mug shot being booked for a s*!Tload of hallucinogens.

Originally Posted by Marty Cortez

That avatar is some hippie's mug shot being booked for a s*!Tload of hallucinogens.

Like I said I keep thinking of that as BG's real photo...

Originally Posted by BajaGringo

Just curious, for those of you off-grid - what is the "normal" voltage you see on your battery bank in the early morning on an average day before your panels "wake up"???

This morning I had used 188 amp hours (of a 2968 ah Concorde AGM bank) and I was at 12.7 volts. I did have a slight load though as my laptop and internet sat. dish were running, which may have been drawing down the voltage a tenth of a volt or so.

That is one sanitary set up... BG, but I would not expect anything but ...

I have had a few from online who I met in person who seemed genuinely disappointed to discover that was not really me. Maybe I should just change my look!!!


The system is still going through some changes as I need to add in a couple more fuses, shunts and grounding as well as hook the pentametric back up.

Originally Posted by BigWooo

This morning I had used 188 amp hours (of a 2968 ah Concorde AGM bank) and I was at 12.7 volts. I did have a slight load though as my laptop and internet sat. dish were running, which may have been drawing down the voltage a tenth of a volt or so.

How many amps do your panels put out at Pmax during the day???


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Originally Posted by BajaGringo

...Maybe I should just change my look!!!...

Originally Posted by Marty Cortez

That would be an improvement...




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Originally Posted by BajaGringo

How many amps do your panels put out at Pmax during the day???


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I have 175 watt panels. According to the spec sheets, at 77 degrees under a partial load, it should be 125.1Wp.

I just checked mine under a partial load at 12:30 (not getting full sun yet) and 86 degrees out I'm producing 122.4w per panel at the charge controller. My panels are much hotter than the test temp and they won't get max sun for about another hour. If I can remember, I'll check again in an hour.

Oh....by the way BG. That IS A NICE setup!

Originally Posted by BigWooo

I have 175 watt panels. According to the spec sheets, at 77 degrees under a partial load, it should be 125.1Wp.

I just checked mine under a partial load at 12:30 (not getting full sun yet) and 86 degrees out I'm producing 122.4w per panel at the charge controller. My panels are much hotter than the test temp and they won't get max sun for about another hour. If I can remember, I'll check again in an hour.

And what is the max average amps going into your battery bank via your controller at the peak sun hour? (ie 60 amps at 14.5 volts) Do you use MPPT?

Originally Posted by BigWooo

Oh....by the way BG. That IS A NICE setup!

Thanks my friend - wait til I'm done as it has a ways to go and should look a lot better when finished. The batteries will all be enclosed and vented as well...

Originally Posted by BajaGringo

And what is the max average amps going into your battery bank via your controller at the peak sun hour? (ie 60 amps at 14.5 volts) Do you use MPPT?

Yes I use MPPT. I'm using Outback FM80's

I went back to check peak output, but It went into absorb mode right after I last posted and before the sun peaked (which I think is about 2:00pm), so I couldn't check what the max output would have been. At last check, at about 12:30, right before it went into absorb mode, one string of 5 panels was producing about 51amps, the second string of 4 panels was producing about 41amps for a total of 92. I don't remember the bulk voltage though, I'll have to check tomorrow while it's in bulk mode (I can't find it in the documentation).

Originally Posted by BigWooo

Yes I use MPPT. I'm using Outback FM80's

I went back to check peak output, but It went into absorb mode right after I last posted and before the sun peaked (which I think is about 2:00pm), so I couldn't check what the max output would have been. At last check, at about 12:30, right before it went into absorb mode, one string of 5 panels was producing about 51amps, the second string of 4 panels was producing about 41amps for a total of 92. I don't remember the bulk voltage though, I'll have to check tomorrow while it's in bulk mode (I can't find it in the documentation).

It sounds like you and I are in the same boat, both needing a couple more panels. I see a lot of folks recommending to me to keep my ratio of panels to batteries at a minimum of 5% but preferably 10% in terms of amps charge rate:total 20amphr capacity. I am looking to add another kW and am shopping panels right now.

They tell me that if your loads are light and very few cloudy days you can usually get away with 5% but 10% seems to be a number that most suggest to get the batteries up to bulk quickly and allowed to float the rest of the day which they say will extend their life supposedly.

Might not be a bad idea to rewire your setup to 24v and get a new inverter unless you are running 12v loads. Used inverters sell pretty good down here...