New System, Problems, Solar Daiquiris
Stan-the-Hermit called Friday, needing some bits and pieces to finally get his 24v solar power system running. He’s had his panels for well over a year, having accompanied me on my final run to John’s old Miami Gardens warehouse. They’ve been mounted for months. He left my place happy with an armload of switches, breakers, fuses and solar wire. If I had more friends like Stan I could open a solar hardware store.
I expected to receive a triumphant phone call within 24 hours, but that didn’t happen. He was in a panic when he called Saturday. He’d hooked it all up right, he claimed, but the voltage on the batteries had gone from 17v down to under 13 overnight. What could be wrong? The answer is right there, but let me give you some background.
A while back Stan told me he’d found a Great Deal on some used batteries that came out of a motor coach. “Great Deal” and “used batteries” can, but do not always coincide. Given the voltages he quoted at the time it was clear that they needed a good charging and equalizing and that one might have a dead cell. He did not charge them, resulting in 4 six volt batteries adding up to 17 volts when he connected them in series. I suspected I knew what the problem was and asked if he had read the manual.
“I hooked it up right,” was the answer, but not to what I had asked, so I asked twice more. No, he had not. I braved 4 miles of bone-crushing gullies, terraces and switchbacks to get to his cabin to take a look. He had hooked it up right, as he’d claimed, but it was settled in on 12.8v, which is fine for a 12v system and a real problem for 24v. He could not find the manual, of course. I suspected the charge controller had autodetected the system voltage as a well-charged 12v system and proceeded to run the battery down to 12v overnight.
We hot wired two panels directly to the batteries to get them charging. I left him with instructions to let them get up to a bit over 30v so they could equalize and desulphate and to keep an eye on the water levels. Batteries that dead should have taken a few days, but he was impatient. By Sunday morning the voltage level had come up to 27 volts and he was ready to hook up the charge controller and inverter. That is not what I had prescribed, but it would not hurt anything and might save some damage that could occur if he went away, leaving the batteries unregulated.
I stopped by about 6:00 Sunday afternoon and Stan was a happy camper. I poked at the charge controller and saw that the battery was still taking
50 watts, even as the tall trees up the valley slope were shading his panels. He’d had some of his inner circle over and they’d inaugurated the new 24 volt power system by making daiquiris! It was clear they’d been successful in that endeavor.
He still has 8 more panels and another charge controller to connect before it is done. When he moves his Flexmax 60 over from the 12v system it will be just the ticket for getting those batteries equalized because it can be manually set up for a thorough job, unlike a lot of other controllers that give a mild boost on a daily basis.
By the way, I found the manual online and his charge controller autodetects a 24v battery in a range of 18-30v, so it really did think it was dealing with a 12v battery. Whether you buy your batteries new or used, charge them up before storing and again before putting them into service. Just sitting around discharged is bad for them and confusing to a charge controller. RTFM (read the fine manual).
As for what you use to test your new power system, a blender is as good a start as any.
By: Neal Collier
Time to Hang it Up!
I like wristwatches, especially ones with classic art deco styling. I quit wearing them when I had my hands in commercial radio transmitters a lot. Other people got away from wristwatches for a while, having their phone has an accurate timekeeper, but watches are making a comeback. They are becoming quite the investment, too.
If you have a Patek Phillipe Grand Complications Celestial model, you probably have your people work on your solar system. I leave the Girard Perregaux Gyromatic in the watch box when I am just knocking about, preferring one of my big Timex Weekender variants because I can see the contrasty face with my iffy eyes. Whatever is on your wrist, maybe it shouldn’t be when you are working on your solar power, or any electrical equipment.
One of my pieces of safety equipment is a long screw on a low rafter, off to the side of my control panel. You could use a nail or, if you have a finished room, maybe something civilized like a Shaker peg. That’s to hang the watch on, along with any rings or other metallic accessories you might have.
Whether it is a Timex or a Tourbillon, hang it up when working around power.
Getting a watch into solar string voltages will make for a real nice conductor, allowing you a fairly quick, if agonizing death. A 12v battery might well weld you into the circuit and give you an awful burn. The nylon or leather straps on two of my Weekenders make them smaller targets, but targets just the same. Getting into a 24v circuit with a Twist-o-Flex you might be able to save the hand if you are fast enough. The heavy stainless bracelet on my Wittnauer or my Lord Elgin in contact with a 48v circuit might well just burn the hand off as the band vaporized.
Sorry to sound so gory, but safety is no accident. In this case, prevention costs a couple of cents for a nail and a few seconds of your time. Hang up that Portugieser and get to work!
By: Neal Collier
Why not?
I figure anybody who has built a solar power system has good reason to take pride in their work. I know I am proud of mine, but now I am a little dismayed. My system is just a solar-roofed shed. It is practical and it works, which is fine, but now I have seen that others with a little more room and a bigger budget are also having fun with their systems. I am jealous.For example, there is a Duke installation at Disney Orlando, like you couldn’t figure that out for yourself.
And what is the national symbol of China? The Panda. There are over 100 panda-themed solar power stations in the works. The photo below is a design rendering, but this station is now on line. They use different panel coatings to get the shading.
Fiji is getting in on the panda craze, too, though this one looks crudely photoshopped.
And here’s a nice one in the “heart” of New Caledonia.
Y’all make some solar power, but let’s have some fun with it, too!By: Neal Collier
Waiting my turn in Nawlins
Is that a smile or did I just put my elbow down on a hot PV module? I’m catching some rays through the sliding module hatch of my solar expedition launch, Sun King. This is at New Orleans, home of the weirdest lock and drawbridge combination I have ever seen. 1620 watts of “B” panels on the boat.
Are you afraid of “B” panels? I’m not. I put six of them on my solar-powered expedition launch Sun King and travelled up to 1000 miles from home. My longest trip was 1920 miles in 44 days. Lots of rivers and the Gulf of Mexico. These days I don’t wander so far off and only have 3 modules in the middle and rounded edges on ends. 9 big 335 watt panels are going on my solar yacht project and I plan on taking that on a 6000 mile trip around The Great Loop. “B” panels are reliable and cheap, so you can afford more solar stuff, like batteries and charge controllers, all of which Sun Electronics has, of course.
Just planning to keep the batteries charged on your sailboat or cruiser? Save money with so-called 24 volt panels instead of 12 volt panels. Use an MPPT charge controller and the 24 volt panel charges your 12 volt battery bank at top efficiency. By: Neal Collier
Solar everything, even the honey dipper!
If you spend much time around boats you know that you can’t just flush overboard. The holding tank has to be pumped out on occasion. Now there is a solar-powered roving pump station.
In my opinion, they got this wrong. There is way too much motor on this thing, probably because it was set up by the motor maker. Or maybe they can actually get that rig up on a plane, for speedy service. Torqeedos have a fair reputation if you can tolerate the noise they make. Where it is underpowered is up top.
They are going to have to plug this thing in at night if they use it much or if it has to travel very far. It is a FREE service for boaters and won’t use any gas, so I shouldn’t be too critical.
By: Neal Collier
Photo credit to http://www.solardaily.com
Inquiring Minds Want to Know!
Over the weekend we really went to extremes to show just how tough solar panels can be. Today we’ll tell you the results.
We started with a Suntech STP280 that had been hit by a tractor. The frame was bent, wires were ripped loose, glass was shattered and many of the internal cells were broken. Short circuit current of a shiny new panel should be around 8 amps. Open circuit voltage should be 44V. In the “as found” condition, we had 4.5 amps and 43 volts. Connected to a load we could get about 68 watts. Not bad for a module someone had thrown away.
Especially for a panel that looked like this.
And to recap what happened next:
After the shooting, I measured output under varying conditions. The hole sure was a handy place to put a voltmeter!
And the open circuit voltage was….39V.
Next I added a 24V driving light as a load. The lamp pulled .961 amps at 24V or 23 watts. That’s all the lamp needed. Was there more?
Next, I added a 12V battery, to be charged, and an ammeter.
Now we have 2.508 Amps at 13.8 Volts for 34 watts.
How about 2 batteries in series and the light? 26.2 Volts X .880 Amps = 23 watts
Here’s a look behind the scenes…no trickery, just honest destruction.
Conclusions? Obviously, PV modules work better if you don’t smash them with a tractor, shoot them with a pistol and shoot them again with a shotgun. The worst damage appears to have been done by the tractor. That hit took it down from 280 watts (rated) to 68 watts. The first two shots, from a .45 and a 12ga. slug, had no effect on the output. It was the huge hole from the shotgun when I backed up that cut the output in half. The point is that the panel continues to output usable power and it did a good job of topping up those batteries.Oh, and remember “Don’t Try This At Home.”By: Neal Collier
Here’s a handy idea for after a storm
You know those little solar sidewalk lights? You can put them outside during the day and bring them in at night. I wouldn’t read by one, but you can find your way around the house with it and it is safer than a candle. Most of these have a AA or AAA battery in them, either NiMH or NiCd. You can put regular alkaline AA or AAA batteries in them if you want them to run all night.
Just keep them inside and they will last for days, if you don’t want to worry about someone stealing them or have them submerge when it floods. Whenever I remove a battery that won’t run the blood pressure machine or other small gadget, I put it in a box if it has any life left in it. They will still last a long time in a super low drain application like running that one tiny LED in a garden light!
This works in a condo, too!
By: Neal Collier