Best Deal in UPS Shippable 12v Panels?

Re: Best Deal in UPS Shippable 12v Panels?

brulaz wrote: »

Also when you calc $$/watt (including shipping) the kyocera's come pretty close to the chinese stuff because they are 135W versus 120W, and yet the UPS shipping is similar ($30-35/panel for my destination).

Finally I think they are being sold for $720 a pair at NAWS.

I was using actual charges in the shopping cart with freight to my northwest location. So my $$/watt numbers take all of the above into consideration. The numbers:

2 Kyocera 135 watt $782 shipped = $2.89/watt (from NAWS)

2 UL Solar 115 watt $629 shipped = $2.74/watt

2 SunTech 150 watt $718 shipped = $2.39/watt

NAWS sells the 170 watt version of the SunTech panels but at a much higher price which is why they didn't make my initial list. Several people report good results with SunTech. So, I agree with Windsun, given the unknowns around UL Solar, I'd pick, the SunTech's or Kyocera's.

The Kyocera's are 13.5% efficient, while the SunTech's are 11.8% - 13.3% depending on which "grade" you get. So while one is poly and the other is mono it doesn't seem to make a big difference in terms of size vs output.

So the choice is really down to the Kyocera or the SunTech's. But, as I mentioned, the SunTech's in my application would require a 24v input/12v output controller with decent ones starting around $300 and going up from there. So I have to factor that in as well to the total cost. There is the advantage of less wiring loss with a 24v array.

Re: Best Deal in UPS Shippable 12v Panels?

solarvic wrote: »

Solar geek, Have you checked the freight charges verses UPS? I don,t trust UPS personally. If the glass gets broken , They will claim it wasn,t packed well. With a trucking co you have a good posibility that they will honor a claim if something gets broken.

Thanks. I wondered about UPS breaking panels. If I needed 4 or more, truck freight would be a no-brainer. But it's rather expensive for just two panels.

I would have to trust whoever is shipping them to deal with getting them here in one piece and, if there is any freight damage, hopefully getting it handled at no cost to me. It's similar with large flat screen TV's. They're famous for being damaged in shipping and are usually worth many times more than even an expensive panel. I saw a bunch of them stacked up in a warehouse of a damaged goods company. Several looked like someone threw them off the roof. The guy working there saw the amazed look on my face and said "UPS!". Sure enough, nearly all the boxes had UPS shipping labels on them. It was probably a $20,000 stack of TV's that will likely end up in a landfill somewhere.

Thanks to Solarvic and RanomJoe also for your helpful input.

Re: Best Deal in UPS Shippable 12v Panels?

RWB wrote: »

I would never use a charge controller that was not MPPT because I would always know that I was probably getting less current out of my panels then what I could be with a good MPPT Charge Controller.

Thanks I mostly agree. The difference in this case is the relatively inexpensive decent quality MPPT controllers, like the Blue Sky 2512, don't support going from a 24 volt array to a 12 volt battery.

I'm not aware of any MPPTs under $300 that would work (besides the BZ Products, but from what I've read, it doesn't properly double the charge current going from 24v down to 12v and has other problems).

The Morningstar Sunsaver can't handle 300+ watts. So the least expensive MPPT controller I know of that would work is the $300 Rogue 3024 and it's missing at least one key feature I need. So I'd probably be looking at one of the higher end Blue Sky's or the Morningstar Tristar 45 in the $430+ range. With a 12 volt array, however, the Blue Sky 2512 would work great for about half that price.

The bottom line is the Suntech panels go from $2.39/watt to $3.06/watt if you factor in another $200 for a more expensive 24/12 charge controller.

Re: Best Deal in Panels & MPPT Controllers

brulaz wrote: »

Have you looked at the Rogue controller?

I have, I mentioned it in the same post you quoted...

mikeo wrote: »

I'm just curious, which feature do you need that is missing? The only feature I have found lacking so far is I wished is that it would handle a VOC of at least 90 volts instead of 60 volts so I could series 3 panels for a 24 volt system.

First let me say the Rogue MPT-3024 looks like a really good deal in many ways and I've read many favorable comments on it. I also really like the fact it's made in Oregon by an entrepreneur who's trying to support the DIY solar community.

The big thing for me is the Rogue doesn't have a low voltage disconnect (LVD). Most of the other MPPT controllers have that feature--even cheaper ones like the Morningstar Sunsaver and lowly BZ Products. I'm not always around to babysit the system, and in cloudy weather, an expensive bank of batteries could be easily damaged by DC (non-inverter) loads. It's cheap insurance to have an LVD. Granted there are other ways I could implement one but it really belongs in the controller in a small system like mine. If the only load on your batteries is an inverter, you probably don't need LVD as the inverter will shut down on its own.

The Rogue also doesn't have any sort of agency approval but I don't think Blue Sky or BZ do either. Even Morningstar only has CE approval which probably doesn't help you much in the USA. From what I've seen you have to spend a lot more to get a true UL certified controller.

That said, a neighbor had a fire in their house while they were away and their insurance company refused to pay for the damage claiming it was due to un-permitted wiring that was done during a minor remodel job. The insurance business isn't what it used to be with the likes of AIG, corporate greed, etc.

I suspect in many small DIY systems the surge suppression in the charge controller is the closest they have to lightning protection (even though it's not intended for that). It's also the most likely ground point in a lot of systems. So if there is a nearby or direct lightning strike, the controller is the most likely thing to blow up. And if there's a fire it's conceivable an inspector could point to the fried controller as being suspect.

But, in fairness to the Rogue, I suspect many DIY solar systems have other brands of unapproved controllers and multiple other code violations. So I'm not sure how much it would really matter if there were a problem? In the case of lightning, for example, the inspector might blame improper grounding of the panels rather than the controller.

IMHO *anyone* with a DIY solar system who has a fire or injury where the system could be blamed is probably in for an expensive legal battle with their insurance company. And, just ask my neighbors, the huge insurance companies have way more legal resources than the average homeowner can stand up to.

And, yeah, some similarly priced controllers support 36 volt arrays like the Sunsaver MPPT. One thing to note, however, is the efficiency of all the charge controllers I've seen drops off dramatically when the array voltage is more than twice the battery voltage. They're all most efficient when the nominal Vin is the same as the battery voltage.

If the above issues are not a problem for someone, the Rogue is a great deal. I think the DIY solar community should, whenever possible, support their own including companies like NAWS and Rogue.

Re: Best Deal in UPS Shippable 12v Panels?

mike90045 wrote: »

But another factor is, how much your batteries will accept ? Even really flat batteries, as they charge, in a couple minutes, start to reduce their amps. At that point, a MPPT may have only bought you 15 minutes of "better" charge, once the batteries slow down.

I would say that's simply not true with properly sized batteries in good condition and a decent MPPT. Batteries that are really low should stay in the bulk charge phase at max current a lot longer than 15 minutes.

If you're seeing that the batteries are probably badly sulfated or severely undersized. Or perhaps you're referring to the BZ Products MPPT which others have reported does exactly what you describe. Either way, something is wrong.

Also, a lot of times you have some load on the batteries while they're charging. So that also will tend to keep the MPPT in bulk mode at max current.

Finally, if you're using 24 volt panels, like the Suntech's being discussed here, and have a 12 volt battery, an MPPT is essential. Otherwise you'll get less than half the panel's rated power.

Re: Best Deal in UPS Shippable 12v Panels?

mike90045 wrote: »

I'm not saying they drop out of bulk or that they are bad batteries, I'm saying the first minute, say they pull 15A from the MPPT, 15 minutes later they are 12A,
Where a PWM that only can deliver 12A from the PV, is only going to see a 15 minute shortning of the total charge time, when upgrading to a MPPT controller of the same amp class. I've got 2 MPPT controllers, and it's easy to watch any battery charger, and see the initial amps drop, as the battery charges. That's how most automotive "automatic" chargers work too.

If you have a typical 60 ah car battery, and you put a 25 amp charger on it, I agree with you. But in a proper solar system with a controller and array that can produce 25 amps, the batteries should be more like 250+ ah. And if the batteries are nearly "flat" as you said, they should accept the full output of a PWM or MPPT controller for many hours. Otherwise the batteries are not sized properly or there is some other problem.

To look at it another way, if one 60ah car battery tapers from 25 amps down to 12 amps of charging current. Three of them in parallel (180 ah) would accept 3 times as much or 36 amps so the MPPT would stay maxed at 25 amps.

The battery bank should be sized so you can capture the full output of your array when the batteries are significantly discharged. Otherwise you paid for lots of array capacity you can't use.