how to hook up (30) flexible solar panels with Outback Flexmax and inverter 24v

[sunbelt57]

I've got (30) of these solar panels (PVL-128) from Uni-Solar with the following specs:

(Standard Test Conditions)
(1000 W/m2, AM 1.5, 25 °C Cell Temperature)
Maximum Power (Pmax): 128 W
Voltage at Pmax (Vmp): 33.0 V
Current at Pmax (lmp): 3.88 A
Short-circuit Current (Isc): 4.8 A
Open-circuit Voltage (Voc): 47.6 V
Maximum Series Fuse Rating: 8 A

and I would like to go with the Outback Flexmax (either 60 or 80) and the Inverter for 24v. For batteries I plan on using 8/12/16 6v batteries from Sams Club. What's the best way to connect the panels? All in parallel? Should I use (2) of the Flexmax60's or just (1) Flexmax80?

The panels are going to be mounted on triangle stands at 45 deg and 6 panels per stand. I plan on starting out with (3) stands and adding the other 2 later.

[cdog]

Do some research on the classic!!

[sunbelt57]

It looks like the Classic can handle a lot higher input volts, is field upgradeable (firmware), is not much more expensive and I was looking on their website and the guy that started the company came from Outback which has been sold to Alpha Group which outsourced Outback to India so he has hired some of his laid-off employees from Outback. 

[Tritium]

Get a Classic!  If you don't like it I will trade you my FM80 Outback for it 

Thurmond

[dave ames]

Could do 2 FM80's or 2 150's

With the flexmax 80's..14 modules on one (7 strings of 2 in series) and 16 modules on the other (8 strings of 2 in series)

With the Classic (depending on where you live, how cold it gets and burn in considerations) could maybe run them 15 on each controller with 5 strings of 3..or if it gets chilly where you are, we are back to the 14/16 set up.


 

[sunbelt57]

Thanks Dave.

I may just get a 150 and hook up the 1st 16 panels and add the rest when I save up for the next Classic 150. I'm wondering if I could get by using just 1 3500watt inverter like the Outback VFX-3524. Oh and yes, I live in NE Wyoming so it gets chilly.

[dave ames]

Should be able to fit all 18 from the first three stands on a single 150 running 9 strings of 2 in series..

see the fun calculator:
http://www.midnitesolar.com/sizingTool/

The VFX-3524 sounds like a good choice (from reading..never had one )

Take note that we see those stick on panels may have trouble at anything above a 3/12 pitch..saw somewhere that they sometimes start to slowly slide down when they get hot.

Cheers, Dave

[sunbelt57]

I'm just about ready to order a Midnight Classic 150 (or maybe 2) and I was just curious why on the midnight website they have it for $850 and on this one:

http://www.solar-electric.com/mnclassic.html (Northern Arizona Wind & Sun)

it is for $610. It also shows it in a box with 2 big dump load resistors. I guess I could call 'em.

[cdog]

That pic shows it in the clipper.....a 1000$ option lol.....

[gww]

Will the classic plug into outback hub and communicate with the mate?
gww

[dave ames]

 
Dang, those are some good prices at NAWS!

Yes- they are showing options that we can be sure are not included..eye candy for future sales??

I know how itchy it feels to want to pull the trigger and get something in the works as soon as possible..I would take a day or two and think things out some more

Are you locked into that 24 volt nominal system voltage?  If not perhaps give some consideration to going with a 48 volt set-up? We could do all 30 modules with a single classic 150 and if we can do without the space age display and on board wizard we can pick up the classic "lite" version for only $500 and be done!

Well not really done, still lots of balance of system stuff..Combiner boxes, breakers, wire ect..

Just some food for thought. 

Cheers, Dave
KB1MZF

[Tritium]

Have a look at the Classic Lite. $500 and all it is missing from the regular classic is the Arc Fault protection and the Display. It still has an ethernet interface and can be fully programmed via PC.

Thurmond

[sunbelt57]

I kinda wanted to go with 24v so that way if I could mount the setup close enough to the house then I could run some of the lights and the fridge and freezer straight off of 24v. That's the only reason I wanted to go with 24v.

[gww]

I am not questioning everyones like for the classic.  I would like to know why everyone likes it over the  flexmax 60-80.  The only thing mentioned so far is that the classic handles more voltage.  That may be enough of a reason.  I have the mx 60.  I have never used it yet.  I do know that it is mppt.  It plugs into the hub.  The battery heat senser plugs into the hub.  The inverter plugs into the hub. This is all to create an intigrated system.  Will the classic play well with the outback system.  I have the gvfx3648 system and one mx60.  If I add enough imput to need two cc's, will the clasic work well with what I have?  I am not trying to hijack this tread but feel that sunbelt57 is buying an outback inverter and our answers will be the same.  Also looking at the amount of batteries that sunbelt57 is considering buying would running 24 volt strait to the freezer be that much more efficent than smaller wiring 48 volt and only one charge controller powering through inverter? 
thanks
gww

[sunbelt57]

If I were to go with a 48v system and if I had only 8 batteries all in series to make 48v could I just hook up the freezer across 4 of the batteries? Or the freezer on the 1st 4 and the fridge and lights on the other 4? Or what if I had a relay that kept switching either leg of the the 48 to get more even ware on the batteries?

[gww]

sunbelt57
Do you already have a 24 volt dc freezer and refridge.  Do you already have a bunch of 24 volt dc lights.  If not you can just hook up the 110 stuff in the sub panel and run it all with the inverter.  As you can see from my above post I am a newbie and am interested in the answers I know from exsperence that the members of this board can supply.  In other words don't relie on my answers but wait for the smart people to chime in.
gww

PS 
I have read on here that pulling from just part of a battery bank usually isn't worth the problims it causes.

[sunbelt57]

All I have so far is the 30 solar panels.

[gww]

If you get the outback inverter you may also need a mate to program it probly a hub.  you may need a dc panel box and ac sub panel box etc etc.  If you were to go grid tie you wouldn't need batteries but you wouldn't have back up when the grid is down.  About all you would need to use the panels would be an inverter and permision from the electric company.  Some even give rebates if your stuff is bought new.  If you go with a battery based system you can just wire the loads to a subpanel and power what you need.  This can be done with a smaller battery bank if you can feed the grid.  If you go battery based you really need to look at all the stuff you may not be thinking you need to make sure it will function seamlessly.  You may know all this but I didn't when I was just going to buy an inverter.  If you know already then I am sorry but if you don't please mention it.
thanks
gww

[sunbelt57]

Yeah, I've been reading on this site for a few months and studying the Outback manual. I was going to try to make up my own panel and just buy the DC breakers. I am buying the wires premade with the eyelets to interconnect the batteries and then make my own connectors with the wires from the batteries to the inverter and charge controller. I also plan on using a lightning arrestor and ground rod. Since I live in WY my big enemy is the wind. The triangle sheds I'm building are 18' long, 10' wide at the base and the 2 eight foot sides are sloped at 45 deg. and are about 5.5' high at the apex. The first one is going to have a 2x6 frame as a floor and house all the batteries and equipment. The others are just going to open at the bottom. I plan on using rebar pounded into the ground and strapped to the 4x4s at the bottom to hold it and then some thick plastic to act as a wind brake. There's plenty of wind out here. I can't wait to get started on my wind generator. This is strictly off-grid. Nothing for miles around but sagebrush and cattle. I do have 1 neighbor about 1/2 mile down the road and he's been off-grid for years.

[gww]

Very nice you have some one that is already doing what you want to do.  The neighbor will be a great resorce.  You may have been here;  http://www.outbackpower.com/forum/index.php?sid=3c6b6bd198d16c72fb9a006432803b6c  But if not, it might be interesting to look at.  I  wish you luck.  I am trying something simular but will have the grid to pull me out in emergency situations.  My stuff is home made except the inverters, but simular wattage.  So grid tie is out here also.  I'll be watching your post.
Thanks
gww

[birdhouse]

with the current situation with just PV being purchased, and the initial size of the system being proposed, i'd go 48v for sure. 

just the simple fact of being able to use one spendy CC as opposed to two would be the no-brainer for me.  that extra 5-800 dollars could buy you a super energy efficient 110v fridge/freezer.  there are models out now, that are just about full size that use ~370KWH per YEAR!!! 

if you're really hung up on running stuff without the inverter, you can always string four identical 12v LEDs in series to run on 48v for a few key fixtures that can be turned on before the inverter gets fired up.

i run 24v, but i only have ~600w of solar, and ~600w of wind coming in.  if i was into the multi-KW of incoming power, i'd go with 48v for sure. 

adam

[David Hufft]

I understand your wanting to keep your system 24 Volts but, as it has been said, another CC is expensive. But your fridge and stuff is 24 Volt =/....So, the way to go would be to go to 48 Volts, avoid the second CC, and get a DC to DC converter (much cheaper than another CC or new Fridge) that will take your 48 Volts and make it 24 Volts. Then just run your 24 Volt stuff off of that.

You never NEVER want to pull off of just 4 batteries in an 8 battery bank.

[sunbelt57]

On another board someone suggested running 48v to your location (kitchen) and use a dc-dc step down converter for each appliance. I like that idea.

[classradiance]

Just out of interest . .
What is the distance from the Panels to the Load or Loads using many Amps.

 

[Mary B]

I use dc/dc for my ham gear, 24 yo 12 volt. Works well and actually improved the voltage at the radio because of voltage drop.

[sunbelt57]

Hey experts: I just my order in and I didn't think to order copper lugs. I bought some alum ones off ebay. Would that cause any problems?

[David Hufft]

If they are pure aluminum then the contact between the copper wire and the aluminum with be very susceptible to galvanic attach (causing corrosion). Most aluminum lugs now days are zinc or tin coated to help deter corrosion, but if you got them off ebay you really can't be totally sure of that.