So many solar options. Is there a standard?

[zboss]

2000 watts is a TON of power! If you are really concerned about $2500 vs. $2300 then maybe just see if you can get all the power you want from $1200 worth of panels and controllers.

My neighbor have almost half the wattage I do (he has a cat I have a mono) and he gets much more usable power out of it because he has far fewer shading issues.

You can always go back and add panels in series if you find you don't have enough power and get the right controller (that can handle the voltage).

[travellerw]

Originally Posted by Serapium

Alright. Based on the earlier comment I did the due diligence and it looks like the controller I referenced above will not support the voltage of 35.83 VDC.

So taking into consideration the recommendation of the eco-worthy controller that presents Version C.

I'd have 6 panels at $1,890 plus a total of six controllers at $612 (assuming no bulk discount) for a total of $2502 with no backup controllers in stock. This gives a total theoretical output of 1890 Watts.

It's this better than Version A?

There is another option.. You could go with a better Chinese controller for just a little more money and do any panel you wanted.

I did a teardown of the Tracer2215BN a bunch of months ago. Its a good controller with very good components and design. I have used it on my boat in the tropics for 6 months now with no problem. It supports voltages up to 150V DC. This controller will also scale for the future as it has completely configurable charge parameters (can do LIFEPO4 batteries). Teardown here.
http://www.cruisersforum.com/forums/...er-137173.html

To the poster that said his Chinese controller put out very low values. I'm pretty sure that was a problem with that specific controller. I have my Tracer 2215BN hooked to a 300W array (yes I'm over driving) and it puts out 280-300w in peak sun.

[socaldmax]

Originally Posted by Catamoron

I have to put my 2 cents in even though I haven't read through all the responses - not sure if somebody has posted about not (and I mean NOT) going with a Chinese MPPT controller - we made that mistake and was the biggest waste of $200 I've ever spent. Whoever said to not get hung up on the controller is incorrect - IMHO its the controller, not the panels that you'll get your most difference in output. Go with big solar panels - as big as you can get, and get a MidNite MPPT controller. Our old controller would only put out a max amp of around 25 and any given time - we installed the MidNite with the same solar panels and were making into the 70's at times and regularly seeing up towards 60 amps during most of the day (using an array of 840 watts) - please don't waste your money on anything other than a good controller. Sorry if somebody's already posted this.

Here we run into the problem with asking for advice on an internet forum. Sometimes you get advice that's anecdotal but doesn't pass the sniff test, or calculate out properly.

I have no doubt that this person had a bad experience with a cheap Chinese controller, it might have been a POS. However, you cannot claim that all Chinese made controllers are all cheap POS, just like you cannot claim that all boats made in France are a POS. It depends on the brand, and many of them are as efficient as the top selling brands. It may take a while, but you can find out who's who in the zoo by watching a lot of youtube videos where people used external instruments and a video camera to test the performance of various units.

The video camera comes in handy to ensure they aren't exaggerating or making things up.

For example, to get over 70 amps out of 840 watts of panels would mean the Midnite unit was producing extra energy out of ??? We all know you cannot create energy, merely convert it.

Everyone knows that you never get 100% out of solar panels, even at noon in the middle of summer with the panels pointed directly at the sun.

840w/12V (a ridiculously low voltage = dead batteries) = 70 amps with no loss whatsoever in cabling or the controller. It's impossible. Unless the Midnite's ammeter is waaay off, which would make it defective, or crappy.

840w/13V = 64A, much more believable number, again with no losses accounted for.

840w/14V = 60A, at this point, you're getting the point that a current measurement without a voltage isn't very useful, which is why solar panels are rated in watts, a unit of power.

As charge voltage approaches the fully charged voltage for the batteries in absorption mode, the same number of watts is going to produce fewer Amps, but the watts are what matters.

You will very rarely see full power out of a set of panels (which is why I liked your use of "theoretical output".)

I've installed at least 10 of the Eco-worthy controllers and in post install testing, they put out what the display indicated, which tracked OK with the rated output of the solar panels considering the angle of the sun and time of year.

With regards to the Tracer series of controllers, based on travellerw's posts, I bought a Tracer 4210 with remote display and temp probe. It looks well built, has an easy to read, simplistic display (pictograms of solar panel, battery and lightbulb) but it was producing lower output than I expected (peak readings of 6.8A @ 13V) for a total of 88w output from a 205 watt panel pointed directly at the sun in Oct.

What bothered me most is that the MPPT software for the unit doesn't settle on one voltage, it's constantly searching, slowly, and can vary (in this case) from 30v down to 20v and never staying at the optimum voltage of 27v for that panel.

Here is a chart of solar panel voltage vs current, showing the maximum power point (the "knee") and how the curve shows decreasing output above and below the "knee."




The Eco-worthy controller seems to find the MPPT quickly (as a good controller should) and only changes voltage in relation to changes in sunlight levels.

The Tracer controller, however, was constantly sweeping, dropping to 20v, 23v, 25v, going up to 30v, and as it spent time at these non MPPT voltages, output current dropped from a peak of 6.8A to 4A, or 3.5A, etc.

It's a well built, nice looking controller, but the entire purpose of it is to find and maintain the Maximum Power Point of the output of the panel, and in this it does a lousy job.

A very good demonstration of this problem (along with it's inability to lock onto the I/V curve and needing a reset) is demonstrated in this youtube video. My experiences were identical.

https://www.youtube.com/watch?v=dFuZywwpfaU

I can't recommend a controller that spends the majority of it's time not properly tracking the max power point.

I don't know what I'm going to do with it, unless travellerw is looking for a 40A controller.

[travellerw]

Originally Posted by socaldmax

With regards to the Tracer series of controllers, based on travellerw's posts, I bought a Tracer 4210 with remote display and temp probe. It looks well built, has an easy to read, simplistic display (pictograms of solar panel, battery and lightbulb) but it was producing lower output than I expected (peak readings of 6.8A @ 13V) for a total of 88w output from a 205 watt panel pointed directly at the sun in Oct.

What bothered me most is that the MPPT software for the unit doesn't settle on one voltage, it's constantly searching, slowly, and can vary (in this case) from 30v down to 20v and never staying at the optimum voltage of 27v for that panel.

The Eco-worthy controller seems to find the MPPT quickly (as a good controller should) and only changes voltage in relation to changes in sunlight levels.

The Tracer controller, however, was constantly sweeping, dropping to 20v, 23v, 25v, going up to 30v, and as it spent time at these non MPPT voltages, output current dropped from a peak of 6.8A to 4A, or 3.5A, etc.

It's a well built, nice looking controller, but the entire purpose of it is to find and maintain the Maximum Power Point of the output of the panel, and in this it does a lousy job.

A very good demonstration of this problem (along with it's inability to lock onto the I/V curve and needing a reset) is demonstrated in this youtube video. My experiences were identical.

I can't recommend a controller that spends the majority of it's time not properly tracking the max power point.

I don't know what I'm going to do with it, unless travellerw is looking for a 40A controller.

Socaldmax... I have actually been communicating with that Youtuber who made the video (check the video comments).

While I agree this controller is slow in a DYNAMIC situation, it has not been an issue for me. In the real world, my controller doesn't "constantly" sweep. However I agree it takes more time then it should to find the MPP and some power is wasted.

I have also been in communication with the factory and they assure me a new firmware is forthcoming to fix the problem.

To me, the quality engineering and flexibility of the controller is worth some teething issues in the software. That controller controller has survived being over driven in a closet at +40-+50 the entire summer and survived.

Personally I cannot recommend the Eco-worthy controllers due to thier business practices!

[socaldmax]

How does that affect the customer?

Every time I've ordered one, it's shown up in about 3 days, which must be air mail. Sounds like I'm getting good service to me.

Again, why would anyone buy a MPPT controller that cannot determine MPPT?

If yours works perfectly, why have you been talking to the factory about new firmware?

Things just aren't adding up...

If you're interested in the Tracer 4210, I'll let it go for $150 delivered. That's a bargain for a 40A MPPT controller with remote display and temp. sensor.

[travellerw]

Originally Posted by socaldmax

How does that affect the customer?

Every time I've ordered one, it's shown up in about 3 days, which must be air mail. Sounds like I'm getting good service to me.

Again, why would anyone buy a MPPT controller that cannot determine MPPT?

If yours works perfectly, why have you been talking to the factory about new firmware?

Things just aren't adding up...

If you're interested in the Tracer 4210, I'll let it go for $150 delivered. That's a bargain for a 40A MPPT controller with remote display and temp. sensor.

It has nothing to do with shipping speed. The Eco-worthy controllers design was directly stolen. No not copied, actually stolen by the Chinese company. Do some research, the details are out there. If that doesn't bother you, then have at it. For me, as a software/hardware designer, its unacceptable.

Not sure where I said "Mine works perfectly". I actually said, "In the real world, my controller doesn't "constantly" sweep." Then went on to admit it is not as fast as it could be. This would be why I have been communicating with the manufacturer about a new firmware..

Your passive aggressive comment of "Something not adding up" is a waste of breath... Then its laughable you offer to sell me your controller in the next sentence..

[socaldmax]

Originally Posted by travellerw

It has nothing to do with shipping speed. The Eco-worthy controllers design was directly stolen. No not copied, actually stolen by the Chinese company. Do some research, the details are out there. If that doesn't bother you, then have at it. For me, as a software/hardware designer, its unacceptable.

Not sure where I said "Mine works perfectly". I actually said, "In the real world, my controller doesn't "constantly" sweep." Then went on to admit it is not as fast as it could be. This would be why I have been communicating with the manufacturer about a new firmware..

Your passive aggressive comment of "Something not adding up" is a waste of breath... Then its laughable you offer to sell me your controller in the next sentence..

Considering the Chinese penchant for ignoring patent law, there's a good chance that the Tracer design was stolen from someone else as well. Just not a design with properly working firmware.

If you look on Ebay, there are 3 or 4 different "Tracer" branded controllers, supposedly built by different companies. Maybe they're all licensed mfrs, but probably not, since they're all Chinese.

But again, that's neither here nor there in the real world. What really matters is: "Does the MPPT controller harvest maximum output from the solar array?"

The answer is a big NO, because it spends a large portion of it's time NOT on the MPPT point, as if it cannot determine MPPT.


Perhaps after the promised FW is released (how long has that been now? A year?) it might be a decent controller. For now, I've got a nice door stop or paper weight.

[Serapium]

Socaldmax,

Couple of questions about the eco-worthy. If I'm reading the documentation correctly, it appears that the max open circuit voltage for the unit is 50VDC. Since the panel that I'm considering has an open circuit voltage of 45.55, does that mean that I could only connect one panel per controller? I'm a little confused on how open circuit voltage is calculated when connecting panels in series. I understand what happens to amps/watts but does that same thing happen to max open circuit voltage? In addition, the 315W panel has a theoretical top end of 26.25A at 12VDC, which exceeds the eco-worthy's output capacity. I know you said you're overdriving yours....

I did find another panel at 230W that is also roughly $1/Watt, which would put the output just over 19.1A as a theoretical top.

[Serapium]

I guess this the alternative that I'm looking at now based on the advice above (including the previous suggestion of using 12V nominal panels and cheaper PWM controllers):

I found a 12V nominal panel that's $1.64 / Watt (140 Watt panel is $230). It looks like there are a number of well-made PWM controllers (based on Amazon product reviews) at $22-$25 each.

That would yield the following systems for comparison:

Option A: 10x 140 Watt Panels @ $2,300 and 10 Charge Controllers at $250. $2,550 for a total of 1400 Watts.

-OR-

Option B: 6x 315 Watt Panels @ $1,890 and 6 Charge Controllers at $612. $2,490 for a total of 1890 Watts.

Seems to me that I get quite a bit more bang for the buck at the higher wattage panels. I'd have the benefit of the MPPT controller as well as lower installation costs due to being able to use smaller cabling.

[socaldmax]

Originally Posted by Serapium

Socaldmax,

Couple of questions about the eco-worthy. If I'm reading the documentation correctly, it appears that the max open circuit voltage for the unit is 50VDC. Since the panel that I'm considering has an open circuit voltage of 45.55, does that mean that I could only connect one panel per controller? I'm a little confused on how open circuit voltage is calculated when connecting panels in series. I understand what happens to amps/watts but does that same thing happen to max open circuit voltage? In addition, the 315W panel has a theoretical top end of 26.25A at 12VDC, which exceeds the eco-worthy's output capacity. I know you said you're overdriving yours....

I did find another panel at 230W that is also roughly $1/Watt, which would put the output just over 19.1A as a theoretical top.

Yes, if you're connecting panels in series, you add up the Voc, so 2 x 45.55v = 91.10V. You can't use the Eco-worthy in that setup, but you wouldn't want to since the 2 panels would also produce double the current that it could handle. In that case you'd want a 45A controller that can take at least 100V, preferably 150V.

You're right, the theoretical max. current would be higher than 20A, but nobody ever gets max. power out of their panels. Under perfect conditions, I'd be surprised if you got over 275w out of the panels, especially if they're mounted flat and not on a tracking device. Power wise, they're a good match, since the Eco-worthy can put out 22A and you'll rarely, if ever, see that out of a 315w panel.

I'm not pushing the Eco-worthy, just giving it as one example of a cheap Chinese MPPT controller that works very well, especially for the money. If you look around on youtube, you'll find good reviews on all sorts of controllers. What you need to look for is a guy who uses external instruments to verify what the controller is claiming, compares that to the expected output from the panels, and isn't doing one of those "this here is the box, it's nice and shiny and has lots of colors on it" reviews. They're idiots and just like the sound of their own voice. The Aussie review of the Tracer is a good example of a guy who knows what he's doing. He varied the load, monitored the input and output and noticed the hunting problem.

What I'd recommend is measure your area. Then buy the highest output panels that will fit in that area. I have a customer with a 128"x132" bimini. A 315w solar panel would hang over the edges a little, and he didn't want that. I found some 285W panels that 6 will fit up there perfectly, so we're going with that. I wish the 315's were just a few inches smaller, but that's better than only installing 3 or 4 of the 315s because that's all that would fit.

After you've selected the panels that fit, then select your solar controller based on input V, power, etc. I know brands like Midnite solar, Morningstar, Rogue, Apollo, Outback and Bluesky are all pretty expensive, but they are well known to be good quality. If you try to save a buck on the MPPT controller, do your research on youtube, not on websites, because people's memories aren't as good as a video when it comes to details, and you can verify the person is using at least somewhat of a scientific process.

Don't forget cabling should be at least the recommended size, I like to go 1 size bigger if possible to reduce potential losses.

[Serapium]

Thanks again for all the help, socaldmax. Real estate isn't an issue for us, as we have a 25' wide x 6' deep flat hardtop pilothouse, as well as having a 25' wide by 4' deep raised aluminum rack that is on the rear acting as davits that I could mount on top of. I could fit 8 of those 315W panels on my pilot house roof alone. I'd end up with about a 2" overhang but that wouldn't bother me.

Does the eco-worthy controller produce much heat when going full bore?

[socaldmax]

Originally Posted by Serapium

I guess this the alternative that I'm looking at now based on the advice above (including the previous suggestion of using 12V nominal panels and cheaper PWM controllers):

I found a 12V nominal panel that's $1.64 / Watt (140 Watt panel is $230). It looks like there are a number of well-made PWM controllers (based on Amazon product reviews) at $22-$25 each.

That would yield the following systems for comparison:

Option A: 10x 140 Watt Panels @ $2,300 and 10 Charge Controllers at $250. $2,550 for a total of 1400 Watts.

-OR-

Option B: 6x 315 Watt Panels @ $1,890 and 6 Charge Controllers at $612. $2,490 for a total of 1890 Watts.

Seems to me that I get quite a bit more bang for the buck at the higher wattage panels. I'd have the benefit of the MPPT controller as well as lower installation costs due to being able to use smaller cabling.

I simply do not agree that well made PWM controllers are good enough. I have never and will never install a PWM controller because there are affordable MPPT controllers, and maximizing solar harvest is an exercise in percentages. It's all about getting the highest performing panels that will fit, losing the least amount of power in the cabling, mounting them where they will get shaded the least, and feeding that power to a controller that will maximize output under all conditions. Early in the morning and late in the day, for example, I've seen higher V panels produce 20v @ .4A, the MPPT controller converted that to .62A @ 13V and was putting that into the battery BEFORE the sun had come up over the horizon. The lower voltage 17v panel was only making 12v at that time and was producing no charge through an identical MPPT controller. Once the sun rose, the higher V panel still held a slight output lead until the sun was closer to overhead. The point being, an extra .62A here and there, multiplied by 7 panels, by a couple of hours in the morning and evening adds up to an extra 17.36AH per day, which is nothing to sneeze at.

I think you're budget is a little tight. I gave an estimate for 6 x 285w panels system that cost $1/watt and it was $5,800. Sure, the panels only cost $1710, but tax is $140, freight is almost $300, 3 x 60A Morningstar controllers with remote display was $2175 plus $175 for tax, $1000 for labor, about $300 for materials.

Subtract labor and your cost is $4800, that's if you can wrangle a couple of friends into helping and don't offer them any beer. Otherwise, add in a few cases of beer.

[Serapium]

I haven't really set a budget yet, but have been using the $2500 point as just a rough way to compare several varied configurations. In terms of panels, I'll be picking them up in person so no shipping and only a short drive away. Will be doing the entire install myself so no labor. I figure after tax (assuming I went with the eco-worthy) I'll end up somewhere around $3000 installed if I don't alter the design from the one listed above.

[socaldmax]

Originally Posted by Serapium

Thanks again for all the help, socaldmax. Real estate isn't an issue for us, as we have a 25' wide x 6' deep flat hardtop pilothouse, as well as having a 25' wide by 4' deep raised aluminum rack that is on the rear acting as davits that I could mount on top of. I could fit 8 of those 315W panels on my pilot house roof alone. I'd end up with about a 2" overhang but that wouldn't bother me.

Does the eco-worthy controller produce much heat when going full bore?

Yes, it gets pretty warm at max output. I wouldn't mount them in an enclosed space, unless you ventilated it and added a 12v fan.

Depending on your power usage, you might end up like me with fully charged batteries by 1030am. On my trailer, I have 2 x 155w panel and 1x 165 all connected to a 25A BlueSky controller. 475w exceeds the max. of the controller, but since we rarely see full power, I usually see 14 -15A early on, maybe up to 20A, then it goes into float by 1030.

So I bought a 120v portable ice maker and run it from breakfast to dinner. Not only do I get 25 lbs of fresh ice per day, but I'm now using some of that solar power that I wasn't harvesting at the peak of the day. This was feeding a 675AH bank of golf cart batteries, and I use power as needed, even though all of my lights are LED, etc. Now that I've made things more efficient (sealed air leaks in the trailer, switched to LED) I can pretty much use all of the power I want powering 3 LCD TVs, 3 DVRs, tons of outdoor lighte, run the furnace, etc and the batteries are still fully charged very early in the day.

Keep in mind, your electrical system is a complete system, you need battery capacity to store all of that solar power, time your high usage loads during the day when solar power is at it's peak, etc. I'm not claiming that one can have too much solar power, just be mindful if your batteries are in float mode most of the day, either you can afford to use more power during the day, you need a larger battery bank or you might have over spent a little on solar.

leftbrainstuff is a very intelligent guy, his suggestion to start small and expand if necessary is great advice. Unless you're positive through measurement and calculations that you'll need a 1890w system, you could always start with 1260 watts, or 900 watts and see how it works out.

[Serapium]

Actually, when it's all said and done 2000 watts isn't going to be NEARLY enough. Large fridge and freezer, big watermaker, six people, big flat-screen, four laptops getting frequent use in video and audio production, electric stove top, espresso machine, ice maker, electric skateboards, etc etc.

The biggie though, is ditching fossil fuel entirely and repowering all electric. Power hungry electric inboard and pull the diesel entirely, plus an electric outboard for the dinghy.

I haven't done the full power budget yet for the end vision, but I'm guessing we'll end up north of 5000 watts of generation capacity between solar, wind, and towed array. Probably have something like a 4000AH battery bank as well.

If you're interested (or wouldn't mind giving some advice) I wrote a post about it on our blog.