question can 12v panels be wire for 48v system?

[goldhunter_2]

I have wanted to go solar for awhile now just can't seem to qualify for these incentive programs to help out ..........I have finial decide I would buy a little at a time on my own. I have already installed solar pool heating panel , and going to pick up a solar hot water heater panel soon but the big expense for me comes with the grid tie solar PV panels. I have decided to buy panels in two or three phases (as budget allows basically) I want to use a 48v system to be the most efficient and save some cost on the carrier wire , finding 48v in standard panels is simple so are inverters. At a later point I would like to add a 48v battery bank also but can only do a little at a time.

BUT for my first phase panel buy I am looking at thin film peel and stick pvl-68 by the bankruptcy company uni-solar. I believe I can pick up some for a reasonable prices and I wouldn't have the cost of mounting rails and brackets plus they are a perfect fit size wise for the area I have (yes I know bankrupt equals no warranty and thin film is less productive per sq foot) but they are the simplest and cheapest for me to start with and will fit 50 (3.4kw) of these on my lanai roof witch is 11' deep by 64' wide. This would be grid tie and would have there own inverters but I would just prefer to have everything 48v in case I ever have to switch inverters around down the road

NOW to my question: the unisolar pvl-68 are 12v panels can I wire 4 12v panels in series to make a 48v panel similar to the way you would wire 12v battery's to make a 48v battery bank? thus allowing me to use smaller copper wire and 48v inverters

[inetdog]

Ire 4 12v panels in series to make a 48v panel similar to the way you would wire 12v battery's to make a 48v battery bank? thus allowing me to use smaller copper wire and 48v inverters

You can indeed wire four nominal 12 volt panels in series to build a nominal 48 volt system for use with a PWM charge controller. But when you are working with the amount of power that justifies a 48 volt battery bank, it will be more economical to get higher voltage panels and an MPPT CC.

[goldhunter_2]

Thanks

I was planing 280watt to 330 watt 48v mono panels for my second phase purchase , I have enough regular roof area to fit around 4-5kw of those , my biggest draw to these thin film panels for my first phase was the fact that they fit perfectly with minim weight on my lanai roof if I used the mono panels the weight and wind load would be to much.

[SunEagle]

Thanks

I was planing 280watt to 330 watt 48v mono panels for my second phase purchase , I have enough regular roof area to fit around 4-5kw of those , my biggest draw to these thin film panels for my first phase was the fact that they fit perfectly with minim weight on my lanai roof if I used the mono panels the weight and wind load would be to much.

Just be aware that those thin film panels will not last long due to heat degradation. That was the biggest issue with them and why they didn't become a major player in the solar PV installs. I was actually hoping they would work since they looked like the perfect solution to a raised rim metal roof.

Also with wiring 4 in series you can only put up 48 of the 50. That will give you 12 strings of 4 at 66 volts and 4.13 amps or 272 watts per string. What type of inverters were you looking at?

[goldhunter_2]

Just be aware that those thin film panels will not last long due to heat degradation. That was the biggest issue with them and why they didn't become a major player in the solar PV installs.

I wasn't aware of that I thought that they where supposed to be good handling our heat???? I thought they went out of biz cause of the price being the same as standard panels and they took up more sq footage. When you say they will not last long what type of time frame 6 months or 6 years out of the 20 something there supposed to ?

What type of inverters were you looking at?

well probably going to start with the cheaper china sun or powerjack until i can buy better

[inetdog]

...well probably going to start with the cheaper china sun or powerjack until i can buy better

Do not use the cheap non-UL-listed plug-in GTIs that you can buy off ebay.
1. They are illegal
2. They are unsafe
3. They are not as inexpensive as they seem at first glance since lots of credible experience states that it they deliver 1/2 of their rated output you will be doing well.

As for totally off-grid, battery powered inverters in the same family, at least two of the above still apply.

[SunEagle]

I wasn't aware of that I thought that they where supposed to be good handling our heat???? I thought they went out of biz cause of the price being the same as standard panels and they took up more sq footage. When you say they will not last long what type of time frame 6 months or 6 years out of the 20 something there supposed to ?


well probably going to start with the cheaper china sun or powerjack until i can buy better

Most pv cells require some type of cooling which is why they are mounted on racks above the roof to let air flow beneath them to help cool them. The ones that you peel and stick have no way to dissipate heat build up so the cells eventually break down. I believe that can last for many month or maybe years but don't know how much since there really isn't data on existing installed systems. The test data did show that they would not meet a 20 year life span like what the other style panels can do.

I don't know if the heat issue was why they went out of business or that the cost per watt per sq foot of coverage made them less than desirable. Also the other types of panels started to get real cheap because of being over stocked so it was hard to compete.

I will caution you to not use any cheap inverter especially those that plug into a wall receptacle. They are not UL listed and can cause fires due to the lack of short circuit protection. You want to use a true Grid Tie inverter that connects to your main electrical panel. If you use something else then you may not get insurance coverage should a fire break out. It is worth spending a few hundred dollars instead of thousands for a house repair.

[SunEagle]

Power Jack Inverter

I just went to look for the Power Jack Inverter you were mentioning and found a few YouTube videos with the words Buyer Beware. I won't post the videos links but I can tell you they show how these cheap inverters will catch on fire. So stay away from them if you value you and your families life.

[goldhunter_2]

Ok I guess the rack with space under it to allow airflow makes sense , Thanks I'll have to see if I can find them cheap enough to be worth the gamble other wise my south facing roof limits me to 4-5kw max


ya'll brought up a few other points about inverters and wall plug in and since the advice is flowing ....lol. Are those china inverters just false advertise? I thought they where UL grid tie? I'd like to eventually buy the American made sonny boys but it would be allot longer before I could afford getting on line if I do those to start.


most of what I've seen the inverters are "plug in" not hard wired , plus FPL requires license electrician to either wire or inspect any hard wire , so a hard wire he'd have to wire the whole system (again effects my budget for something I am comfortable doing) Plan was for each phase of panels I buy was to hard wire a circuit in the main panel to a six plug power strip with the 20 amp circuit on it. The plug to the main panel would be all that is required to be inspected for FPL. (not counting the city building dept signing off on solar system permits) what is illegal about the plug in inverter systems if there actual grid ties with island circuits for the lineman's safety ?

[goldhunter_2]

ya I have seen good and bad on them , do you have any recommendations for a economically inverter for the first few around 1200 watt units

[SunEagle]

Ok I guess the rack with space under it to allow airflow makes sense , Thanks I'll have to see if I can find them cheap enough to be worth the gamble other wise my south facing roof limits me to 4-5kw max


ya'll brought up a few other points about inverters and wall plug in and since the advice is flowing ....lol. Are those china inverters just false advertise? I thought they where UL grid tie? I'd like to eventually buy the American made sonny boys but it would be allot longer before I could afford getting on line if I do those to start.


most of what I've seen the inverters are "plug in" not hard wired , plus FPL requires license electrician to either wire or inspect any hard wire , so a hard wire he'd have to wire the whole system (again effects my budget for something I am comfortable doing) Plan was for each phase of panels I buy was to hard wire a circuit in the main panel to a six plug power strip with the 20 amp circuit on it. The plug to the main panel would be all that is required to be inspected for FPL. (not counting the city building dept signing off on solar system permits) what is illegal about the plug in inverter systems if there actual grid ties with island circuits for the lineman's safety ?

They are illegal because first off they are not UL listed. Second off they do not have the proper over-current protection to keep from overloading the wires in that receptacle circuit. Third they are hand made with little to no inspection for quality or safety. If will cost you more if an inspector is required to finalize a connection but it will also be safer for you and the Electric Utility worker.

Check out those youtube videos on the power jack and you will see that many people have had them fail or worse catch on fire. Your house insurance will not cover a fire from an item that is not UL or accepted by the POCO which in your case is FPL. Mine just changed their name to Duke and I know they would do a thumbs down on one of those plug ins.

[SunEagle]

ya I have seen good and bad on them , do you have any recommendations for a economically inverter for the first few around 1200 watt units

I believe that Xantrex makes a pretty good gird tie but you have to match up the inverter to the total wattage and voltage input. There are other people on this site that can steer you to the right one.

If you go this webs sponsor Solar Town they have a list of solar components. That can give you some idea of what is out there that is acceptable.

[goldhunter_2]

fpl was the one who explained what the inspection requirements for the plug in so I figure I was safe there, I look into the Xantrex. Thanks for all the advice

[SunEagle]

fpl was the one who explained what the inspection requirements for the plug in so I figure I was safe there, I look into the Xantrex. Thanks for all the advice

Most people just plug in these inverters to an existing outlet which is where the problem starts. The breaker for this receptacle is usually shared with other loads plugged into other receptacles. Then you have the issue that the inverters are not manufactured with quality or safety in mind which is why they don't get a UL listing.

If you found a UL listed inverter that could be plugged into a dedicated receptacle which is wired to a dedicated breaker in your panel it is possible that it might pass FPL standards and inspection. I just don't know of an inverter of that type only the ones that are hard wired to a breaker in the panel like the Xantrex. You may want to go back and get specific equipment information that whoever you talked to at FPL had in mind for a plug in type or system. Let us know what you find out.

[goldhunter_2]

I've wired a bunch of house, condo, town homes over the years in GA and MD but wouldn't trust this house wiring down here in Fl it is screwy!!! their circuits are all over the place , I'd only do something like this if I wired a dedicated circuit and know the wire was specifically over sized.


I saw a youtube of a guy here in Florida doing a few panels at a time on his shed he got approved on the two power jacks he said he like them the first few videos but later said one died (his term was blow up think was like a year later) and he upgrade to a single aurduoa said it doesn't cut in and out and gets better power produced. I browsed around at some of those inverters they seem about on the same price bracket as the sonny boy , outback , Aurduoa and others I was wanting to get started then upgrade but I mite just stretch it out and buy some panels now and store inside garage then just wait until I can get a couple better inverters.