Look at my solar system pics and help me finish the project (:

[Amy@altE]

Yup

[Living Large]

sensij, you are absolutely right, and have been saying it all along. I've been so focused on trying to keep him alive, I haven't bothered stepping back to do the loads list.

1.5HP and 3HP pumps for 24 hours a day. Rough, easy numbers of 750W per HP = 750W x 4.5HP x 24 hours = 81,000 watt hours a day (81kwh).

81,000 / 5 sun hours / .67 inefficiencies =24,179 watts of solar needed.

81,000 x 1 day x 2 (50% depth of discharge) x 1.04 temp deration /48V = 3510ah 48V battery for each day. And that's beating the heck out of the batteries at 50% DoD, he should at least double, better triple it.

He has 280W x 24 = 6720 watts of solar and 370ah 48V of battery. 1/4 of the solar and 1/20 of the battery needed.

The reason this was forgotten is I don't believe he took the advice given in the beginning to take this one step at a time. A stack of big automotive batteries and some wire showed up that some other people involved (neighbors, ???) said they wouldn't return, and it was off to the race(way), so to speak. You kind people are trying to help him, and have fallen into the trap you tried to avoid. My .02

[Amy@altE]

Soo, this 24x280w 48v system will be running our 1 and half hp well pump and our 3hp pressure pump. Theyre both 240. So hopefully we've got enough juice. I know during the summer they have a tendency to pump almost all the time for our 5 acres of park like area. At night is when I water all the grasses which can take all night as the sprinklers are staggered to go on at different times ALL night long.
(:

sensij, you are absolutely right, and have been saying it all along. I've been so focused on trying to keep him alive, I haven't bothered stepping back to do the loads list.

1.5HP and 3HP pumps for 24 hours a day. Rough, easy numbers of 750W per HP = 750W x 4.5HP x 24 hours = 81,000 watt hours a day (81kwh).

81,000Wh / 5 sun hours / .67 inefficiencies =24,179 watts of solar needed.

81,000Wh x 1 day x 2 (50% depth of discharge) x 1.04 temp deration /48V = 3510ah 48V battery for each day. And that's beating the heck out of the batteries at 50% DoD, he should at least double, better triple it.

He has 280W x 24 = 6720 watts of solar and 370ah 48V of battery. 1/4 of the solar and 1/20 of the battery needed.

[sensij]

None of it matters. Wire it up however he wants, running a single phase 3 HP pump and a 1.5 HP pump from this will just not work.

The 3 HP pump pulls something like 16.5 A at 230 V, the 1.5 HP pump would pull around half of that. Figure a power factor of something like 0.75, and these pumps will take 4250 W to run. 6720 W of panels is not enough to run a 4250 W load for a meaningful amount of time, even if there was enough battery to support it, which there is not. With those batteries discharging (4250 W/ 48 V) =~90 A, they wouldn't even run for 3 hours at 100% discharge (note the rating at 75 A is 185 min).

So, go ahead, build it, it will shut itself down soon enough, and the batteries will be murdered before any of the long term electrical problems really become an issue. Building this system with anything other than a grid tie inverter is a waste of time and money, and a sad use of panels that could have been installed in a way that truly would have been of benefit to the OP in the long run.

[SunEagle]

I also think he has switched it to all #12 wires, which we have also tried to stop. But I do not believe there will be multiple gauges, but multiple pieces of #12. Which is still wrong.

Yes. I don't have the exact reference but the NEC also doesn't allow you to run parallel wires below a certain gauge and that #12 is in the "too small" a gauge category.

[Amy@altE]

I also think he has switched it to all #12 wires, which we have also tried to stop. But I do not believe there will be multiple gauges, but multiple pieces of #12. Which is still wrong.

[SunEagle]

It's not just you, we have all been trying to stop him. He is not stopping, so I have switched to trying to minimize the damage and try to prevent death.

He has changed what he says he has for equipment many times. His last post said 8 6V L16 batteries. As long as they wire them in series, he will have 48v (that's for him, not you, I know you know that). You may be seeing that he is saying he has 24V panels, which he is wiring in strings of 4.

You are correct. I looked at some of the earlier posts and he does indicate a 48volt battery system. With all the changes he has made and the discussion about those "24v" panels I got a little confused.

I still think a big issue is the multiple gauge wires running in parallel between his equipment and his desire to use AC rated switches and breakers on a DC system. I hope he is wearing fire proof clothing when he energizes his system.

[Amy@altE]

Is it just me or did anyone see the issue concerning the multiple strings of wire in his diagram? [ATTACH=CONFIG]5689[/ATTACH]

From the panels + terminal (1 -#6 & 3-#12), from panels - terminal (1 -#4 & 3 - #12), to the inverter + & - terminal (1 - #2 & 2 - #12). The electric code does not allow you to run different gauge wires in parallel.

Also that inverter he listed is looking for 48VDC input yet the OP has a 24V battery system.

This whole system is an accident waiting to happen. Someone please get him to STOP NOW.

It's not just you, we have all been trying to stop him. He is not stopping, so I have switched to trying to minimize the damage and try to prevent death.

He has changed what he says he has for equipment many times. His last post said 8 6V L16 batteries. As long as they wire them in series, he will have 48v (that's for him, not you, I know you know that). You may be seeing that he is saying he has 24V panels, which he is wiring in strings of 4.

[SunEagle]

Is it just me or did anyone see the issue concerning the multiple strings of wire in his diagram? hollywoodtoday solar sys pic.jpg

From the panels + terminal (1 -#6 & 3-#12), from panels - terminal (1 -#4 & 3 - #12), to the inverter + & - terminal (1 - #2 & 2 - #12). The electric code does not allow you to run different gauge wires in parallel.

Also that inverter he listed is looking for 48VDC input yet the OP has a 24V battery system.

This whole system is an accident waiting to happen. Someone please get him to STOP NOW.

[Amy@altE]

Again, to update, my system is a 12x280w/24v nominal system on one pole then the same system on a second pole. So 24x280w panels in all. With 2 mppt classic 200v controllers and 1 12000w 120/240 aims inverter.


So if our panels will range between 36-45v according to the specs here http://prntscr.com/5oyx6l , this means hes way off. Yet they sell lots of this models and tech support. He said he knew the differences and that these panels would be perfect for the setup.

UPDATE, we are not using 2 outback 80/80 controllers. We bought 2 of these classic 200s http://www.solar-electric.com/misocl...K94BoCWOfw_wcB
sorry for the misinformation.


Thank you, ya he said 24v nominal. Shesh, who knows what there talking about! lol. Thats what I was trying to tell everybody, but I dont know to begin with. So you're saying 2 guys at sunelec.com are prob wrong? These panels will be pushing more like 36x4vmax with 4 in series, not 44.9x4? Anyhow, I think running 4 280w in series should be ok to use with 1 classic 200 controller. you think?

In addition, we also have 8 6v batteries like this--> http://www.atbatt.com/trojan-l16e-ac...1a2RoCurvw_wcB

OK, first, your supplier is telling you what we've been telling you since page one of this post. I am now officially losing sleep over this project with worry. I'm going to start again. Why is your supplier not doing this for you?

The panels are NOMINAL 24V, as we have all been telling you, including the 2 guys at SunElec. What that means is that it can charge a 24V battery bank. You will never see 24V coming out of the panel, that is just a category, like a 12V panel (which puts out 17V to charge a 12V battery). The Open Circuit Voltage, which is the output when they are not connected to anything is 44.9Voc. When it is connected to the charge controller, it is outputting the Max Power Voltage 36Vmp, because having a load on it (the charge controller) pulls the voltage down.

By getting a 200V charge controller with the Midnite Classic, you now have to deal with higher voltages than the standard DC equipment is designed for. So yes, you can do 3 parallel strings of 4 in series, but now you need high voltage breakers going into the charge controller. You need 2 Midnite MNPV6-250 combiner boxes and 6 MNEPV15-300 breakers that are capable of handling the 200V. Each pole will have 1 combiner box and 3 breakers. You also need 6 2-hole strain reliefs to get the wires into the combiner box, and 2 1-hole strain reliefs to get the ground wire into the box. Be sure to ground the metal frames of the solar panels, the metal racking, and bring the ground into the combiner box and underground back to the DC switch, charge controller, and inverter. I suggest a lightning arrestor in each combiner box as well, like the Midnite MNSPD-300-DC.

Near the charge controller, you can do a SquareD HU362RB unfusible 3-pole DC disconnect.

At the output of the charge controllers, you need 100A DC breakers going to the batteries. They can be regular DC breakers now, because you are at the output of the charge controller at the 48V battery bank. Midnite MNEDC100, you need 2, one for each charge controller.

At the DC input of the inverter, you need a 400 Amp DC fuse like http://www.xantrex.com/power-product...se-holder.aspx

I am not familiar with your inverter, as we don't carry them. Read the manual, it will tell you how to connect it to an AC power source like the grid to charge up the batteries. I believe it also has an internal auto transfer switch. You will need AC breakers at the AC input and AC output of the inverter. http://www.aimscorp.net/documents/PI...K%20Manual.pdf

[inetdog]

Do not buy an AC switch for DC, fused or unfused.

+1
An AC rated switch can withstand DC of the same voltage just fine, and can serve as a disconnect IF you can guarantee that it will never be opened under load (that is with current flowing.
A battery voltage DC, like 12V, will not be as likely to sustain an arc when you open it under load, but a string of three 44Voc panels certainly will. All it takes is the switch being opened under load one time too many (which might end up being exactly one time) to cause an arc which could burn you or set the panel it is in on fire.
The danger is even greater after the combiner where you have a higher current in addition to the high voltage.

Similarly do not use AC or automotive (low DC voltage) fuses and fuse holders for high DC voltages. They can catch fire too, as well as not interrupting the fault current in the first place.

[hollywoodtoday]

Again, to update, my system is a 12x280w/24v nominal system on one pole then the same system on a second pole. So 24x280w panels in all. With 2 mppt classic 200v controllers and 1 12000w 120/240 aims inverter.

You are making a common mistake when talking about panel voltages. There are two important voltages to know when configuring a series string, Voc and Vmp.
When operating, the voltage on the panel terminals will range somewhere between Voc and Vmp unless you are using a PWM Charge Controller.
If you are using a PWM controller, the voltage at the input terminals is going to be not more than a volt or two above the battery voltage under charge. Pretty much guaranteed to be less than Vmp. A PWM controller will waste any power corresponding to a higher voltage than that of the PWM input.

Because of that a panel designed for battery charging using a PWM controller will have the lowest voltage possible that will work well with any PWM controller.
That means that the Vmp will be 2 or 3 volts above the highest voltage the battery will charge at. For a 12 volt battery, Vmp will typically be 18 volts for such a panel, but the panel is called a 12V nominal panel.
A panel designed for use with a PWM CC and a 24V battery bank will have a Vmp of about 36 volts, and will be called a nominal 24V panel. Voc will be about 1.2 times Vmp, i.e. 44V, for silicon panels

So when you multiply the 24V figure by the number of panels in a string you are seriously underestimating the string voltage.

So if our panels will range between 36-45v according to the specs here http://prntscr.com/5oyx6l , this means hes way off. Yet they sell lots of this models and tech support. He said he knew the differences and that these panels would be perfect for the setup.

UPDATE, we are not using 2 outback 80/80 controllers. We bought 2 of these classic 200s http://www.solar-electric.com/misocl...K94BoCWOfw_wcB
sorry for the misinformation.

4 of your panels in series will blow up your charge controller. The Voc of the panel is 44V x 4 in series is 176V, not 96V. The charge controller can handle up to 150V. CALL A PROFESSIONAL. Blowing up the equipment and possibly the house is not in the interest of your grandfather.

UPDATE, we are not using 2 outback 80/80 controllers. We bought 2 of these classic 200s which is good for 200VDC and will be running 4x280w in series with this --> http://www.solar-electric.com/misocl...K94BoCWOfw_wcB
sorry for the misinformation.

Thank you for calling a professional. Did you ask them about the rest of the design, or do they just sell panels?

When they said it is a 24V panel, that is nominal, not actual voltage, it says it puts out enough voltage to charge a 24V battery bank, which is 36Vmp. 3 in series will be putting out 108Vmp, not 72V. I can't tell you how many 12AWG strands to use, as it is not the right way to do it. I suggest you get a Midnite PV6 for each pole, install it at the pole, with 4 15A DC breakers in each box, one breaker for each string. That will combine the 4 parallel strings of 3 in series to one combined output per string, and will give you over-current protection, and a way to disconnect the array. The output from each PV6 at each pole will be 108Vmp 33.12A Isc. Each one of these pairs will go to its own FM80.

Do not buy an AC switch for DC, fused or unfused.

Thank you, ya he said 24v nominal. Shesh, who knows what there talking about! lol. Thats what I was trying to tell everybody, but I dont know to begin with. So you're saying 2 guys at sunelec.com are prob wrong? These panels will be pushing more like 36x4vmax with 4 in series, not 44.9x4? Anyhow, I think running 4 280w in series should be ok to use with 1 classic 200 controller. you think?

In addition, we also have 8 6v batteries like this--> http://www.atbatt.com/trojan-l16e-ac...1a2RoCurvw_wcB

--

With all that said, thank you for your thoughts, much appreciated.

[Amy@altE]

I suggest you get a Midnite PV6 for each pole, install it at the pole, with 4 15A DC breakers in each box, one breaker for each string. That will combine the 4 parallel strings of 3 in series to one combined output per string, and will give you over-current protection, and a way to disconnect the array. The output from each PV6 at each pole will be 108Vmp 33.12A Isc. Each one of these pairs will go to its own FM80.

Please read the manual for the Midnite Combiner Box. You can use the MNPV6 with 4 breakers in it. http://www.midnitesolar.com/pdfs/MNPV2-3-4-6_manual.pdf

[Living Large]

Gotcha, yes, I recognize that DC rated units must be built a little different. I just figure that since weve used ac breakers on our previous system which has lasted 20 years, I now dont know if its such a big deal, at least for a small system. As far as these 2 disconnects I was going to use instead of a throw switch, these disconnects are rated for 60a and ill only be putting 30a into them.

I've never seen an exception such as you describe in any code or specification. There are DC boxes available online on multiple sites.

[Amy@altE]

Thank you for calling a professional. Did you ask them about the rest of the design, or do they just sell panels?

When they said it is a 24V panel, that is nominal, not actual voltage, it says it puts out enough voltage to charge a 24V battery bank, which is 36Vmp. 3 in series will be putting out 108Vmp, not 72V. I can't tell you how many 12AWG strands to use, as it is not the right way to do it. I suggest you get a Midnite PV6 for each pole, install it at the pole, with 4 15A DC breakers in each box, one breaker for each string. That will combine the 4 parallel strings of 3 in series to one combined output per string, and will give you over-current protection, and a way to disconnect the array. The output from each PV6 at each pole will be 108Vmp 33.12A Isc. Each one of these pairs will go to its own FM80.

Do not buy an AC switch for DC, fused or unfused.