Proposed Off Grid Cabin Solar Setup..

[epsgunner]

Hi folks..

I decided to do my proposed setup for my offgrid cabin out in SW Texas..

Starting with...

6- 130W 12v Kyoceras in series of 2 (for 24v) and parallel all 3 strings.. 780 array. and 22.17 max amps.. $1250.. (at 72% effeciency it would be 561.6w/hour * 5 = 2808 watts per day)..
Morningstar TS-45 PWM 12/24/48v Controller.. $155
Samlex PST-1000-24A 1000w Pure Sine Inverter.. $350
8-Trojan T-105 (or equivalent). $1200
Wires, brackets, breakers, 6 breaker combiner box.. $364

Total comes to $3319..

The cabin is just 12'x24' with a barn type roof so I'll be adding a sleeping 5-6' lost up top in the back half..

I get 6 hours of usable daylight facing South (in the summer).. (no trees or anything).. I have my angles for the 3 phases as well.. The winter sun is South also..

The needs are:
Water pump @ .9a AC 110v (Shurflo 3 gpm).. (on a switch to limit run to water usage)..
Small fridge 5-9 cu ft. 110v. (going to timer every 3 hours to go on for 1 hour..)
Small 5K A/C for about 2 hours a day MAX (to cool the back 1/2 of the cabin)... 110v (550watt/hour)

The reason I chose the MS TS-45 controller over the Xantrex is 5 extra amps and the 5 year warranty..

I could MAX my system amperage by doubling to 12 of these panels.. 6 (series) in parallel and be at 44.34 amp max.. The VOC for the circuit is 43.4.. which give me a little cold weather wiggle..

The Samlex has a 2 year warranty as well..

I was going to go with just 24v panels.. but the costs are almost equal.. and I found a good deal on the 130w panels.. the 190w panels x 4 would be $1400 and would produce 760 watts..

I'm buying the controller, inverter. combiner, & wires 1st.. (I have a small 800w 12v inverter here).. then I can use a local cheap small panel to 'play' with here in NJ before I fly back to TX later in the year for the big install..

Then I'll order the panels before I fly out.. then I'll hit my local NAPA for there 8146's.. or local Batteries Plus for the GC125.. (226ah rated 6V)..

What says the crowd?? good starter system??

[bcroe]

Hi folks..
I decided to do my proposed setup for my offgrid cabin out in SW Texas..
Starting with...

6- 130W 12v Kyoceras in series of 2 (for 24v) and parallel all 3 strings.. 780 array. and 22.17 max amps.. $1250.. (at 72% effeciency it would be 561.6w/hour * 5 = 2808 watts per day)..
Morningstar TS-45 PWM 12/24/48v Controller.. $155
Samlex PST-1000-24A 1000w Pure Sine Inverter.. $350
8-Trojan T-105 (or equivalent). $1200
Wires, brackets, breakers, 6 breaker combiner box.. $364

I get 6 hours of usable daylight facing South (in the summer).. (no trees or anything).. I have my angles for the 3 phases as well.. The winter sun is South also..

The needs are:
Water pump @ .9a AC 110v (Shurflo 3 gpm).. (on a switch to limit run to water usage)..
Small fridge 5-9 cu ft. 110v. (going to timer every 3 hours to go on for 1 hour..)
Small 5K A/C for about 2 hours a day MAX (to cool the back 1/2 of the cabin)... 110v (550watt/hour)

Its not clear to me, exactly what the total loads are, do you have any lights or TV?
My inclination would be use mobile home type water pump & fridge, that can run
directly from DC, along with some low voltage LED lights. That will eliminate the
losses of an inverter, and not require an inverter to be on standby or manually switched
all the time. A DC water pump would probably use very little if you're not irrigating.

I would pack my fridge freezer compartment with those freeze packs, should carry it
many hours & save the battery. That leaves firing up the inverter to run the A/C. Make
sure it can handle the compressor start up surge. Running it mostly when the sun shines
(when needed the most) would reduce battery requirements a lot. Bruce Roe

[Naptown]

OK
A couple of things.
Switch the charge controller to an Mppt controller, that is a pwm controller. MS tristar mppt45 is a good one.
This will increase your harvest a bit. or two smaller ones would be better but make sure they are mppt.
With the 2 different pitches on the roof proper tracking will require 2 separate charge controllers. for maximum harvest.
Here is an example of the difference in CC's

load say 1000 wh per day
To calculate array with pwm controller 1000 x2 / daily insolation. so 1000*2/5=400 watts of panels
Same thing with a Mppt 1000 x 1.5 / daily insolation 1000*1.5/5 = 300 watts of panels.

You used the PV watts to calculate and that is really for grid tie and doesn't account for battery losses.

With the AC load this screams for a 48V system You didn't mention what voltage you were using.
I would recommend 8 6V batteries in series. they will charge better and will be less trouble than parallel strings of batteries
48V will also reduce the sizing on the wiring from the batteries to the inverter substantially by reducing amperage draw by a factor of 4 vs a 12V system

The inverter may not be large enough to start the AC unit Check what the allowable surge limits are on the inverter you chose.

Lastly Consider using grid tie panels of 60 cells with the Mppt controllers. You will find that they are a bit less expensive than the 24V you are looking at. With the Mppt controller you could series 3 or 4 of them and reduce the number of strings, increase voltage to the controller, use smaller wire from panels to CC etc etc.

[epsgunner]

For Naptown

8-Trojan T-105 (or equivalent) (these are 6v x 4) 440ah
The TS-45 (non-mppt) was chosen because of cost..
The panels will be mounted on posts and direction-able and tilt-able..

For bcroe..

Water pump @ .9a AC 110v (Shurflo 3 gpm).. (on a switch to limit run to water usage).. <<RV type.. they make a 24vDC version.. but its rated for almost the same draw but in 24v..

Small fridge 5-9 cu ft. 110v. (going to timer every 3 hours to go on for 1 hour..)

Small 5K A/C for about 2 hours a day MAX (to cool the back 1/2 of the cabin)... 110v (550watt/hour)

The only issue may be the 1000 Watt inverter for the A/C.. but its got a 2000 watt surge.. If I start it on fan.. then move to A/C low then high.. it should work.. they come in at 550 watts continuos draw on 110v..

As I get closer to the FLY date I may step up to a 1500 Samlex it may be worth the extra $110..

I'll add 2 x 13watt CFL bulbs at night.. and maybe a laptop..

[Naptown]

Price it my way and I think you will be surprised when you can use less expensive per watt panels, smaller wiring, less voltage drop, ability to wire 3 or 4 modules in series, eliminate fuses, increase harvest, increase potential system size with future upgrades by simply switching charge controller type.
Your choice how you do it. Just giving you the view from the way a pro in a very competitive market would do it. Basically the best, most reliable, system possible for the lowest possible cost.

[epsgunner]

Its going to be a 24v system.. each string is 2-130watt (12v panels).. 17.6 VMP and 7.39 IMP.. the VOC is 21.9.. (35.2 VMP and 7.39 IMP)

I priced some ETSolar 190w (24v) panels with 37.20 VMP and 5.11 IMP.. the VOC is 44.85..

4 of the ETSolar 190w panels is $1260-1378 (pending on dealer).. 760 watts..
even at 52% eff.. I get 395.2 watts * 5 hour = 1976 watts

6 of the Kyocera 130w panels is $1203.. 780 Watts.. same 52% eff.. 405.6 * 5 hours = 2028..

Samlex inverter says 90% eff.. the MS only draw 15 ma in rest..

Running all 3 series (10awg) to a combiner box less than 20' (1.37% drop).. then 6 AWG about 1' to the controller.. then 5' with 6 AWG to the battery bank.. going to use 2 AWG from the battery bank of 24v (440ah) to the inverter about 3 feet away MAX...

Others have informed that the eff rating can be improved with heavy wire and short run..

They call for 8 AWG on the controller and only 6-8 AWG on the Samlex inverter to battery.. I figure 2 should do it..

I am buying the controller 1st.. then testing/playing local with 12v small panel and 12v battery and 12v inverter.. the setup for TX will have the same MS TS45 controller just be set to 24v.. the 24v inverter will also be in the mix for TX..

I understand your in the business.. I don't buy pallets of PV's.. and $1300 is my limit for them.. the 24v panels are bigger & heavier.. I want 750+ watts for $1000 but it won't happen.. unless I buy a pallet.. then the shipping gets me..

From what I understand GT panels are about 30 volts.. these are (or total) over 35..

[Naptown]

For your budget you could get 4 of these
Shipping would be about $200. (get a quote)
this is 1100 watts. these are 72cell modules comparable to 2 of the 36 cell.
Almost 50% more wattage for about the same price.
These are grid tie modules minimum order is one.
Yingli is chinese but quality chinese.

http://www.civicsolar.com/product/yingli-solar-yl275p-35b-275-watts-solar-panel

[Sunking]

Hi folks..

I decided to do my proposed setup for my offgrid cabin out in SW Texas..

Starting with...

6- 130W 12v Kyoceras in series of 2 (for 24v) and parallel all 3 strings.. 780 array. and 22.17 max amps.. $1250.. (at 72% effeciency it would be 561.6w/hour * 5 = 2808 watts per day)..
Morningstar TS-45 PWM 12/24/48v Controller.. $155
Samlex PST-1000-24A 1000w Pure Sine Inverter.. $350
8-Trojan T-105 (or equivalent). $1200
Wires, brackets, breakers, 6 breaker combiner box.. $364

Total comes to $3319..

OK you have made some rather significant erros in your calculations which will bite you in the wallet later.

Fist huge error is you have assumed 72% efficiency. That is not possible with off-grid battery systems. At ver best with a PWM controller the best you can obtain is 50%, and only 66% with MPPT.

Second mistake is it sounds like you are designing based on a 6 Sun Hour Day. You cannot do that with off-grid. You have to use worse case of winter isolation. Not sure exactly where in SW TX you are referring too but using El Paso as an example the Winter insolation is 4 hours. So with that said your system is only going to produce 1.5 Kwh per day vs the 4.4 Kwh you calculated.

Next big mistake is your choice of batteries. The T-105 is a hybrid battery, not a deep cycle battery. Second problem with the battery selection is they are too small requiring you to use two parallel strings to make 24 volts @ 550 AH. Going this route you will need to replace the batteries every year or two where you should be getting 5 to 7 years. For a 24 volt 550AH battery you should be using a true deep cycle battery of 550 AH cells like 6 of Rolls 4CS17P battery. They come with a full 10 year warranty and should last at least 7 years. At minimum if you are just have to use Trojan batteries at least get a true deep cycle model like the T-105RE

[epsgunner]

Sunking..

Heres the skinny for Dec 21st..



and a snapshot for April 18th when I was down there for the cabin to be built..



and for June 21st..



at 52% efficency (which another forum told me) is 780 * .52 = 405.6 * 5 = 2028
(which would still be higher than panels at 760 watts total)

In the winter I will not need the A/C and heat is by wood stove or gas..

The panels will be on a pole system so I can TURN them and also tilt them for the proper degree angle..

I appreciate the tip on batteries.. most have said GC2 batteries are fine.. which will have to do for the 1st year or two.. (that or the NAPA 8146 (225ah) or Rayovac GC125 (226ah)..)

The Rolls are out of my price point.. $811 each for the 6CS17.. and I'd need 4 to get to 24v..

Naptown.. I will check the Civic link when there webserver comes back up.. They quoted me the lowest for the ET 190 panels *4 with shipping at $1255.. so I will check them with these Yn panels..

[Sunking]

In the winter I will not need the A/C and heat is by wood stove or gas..

Air conditioning on solar?

I appreciate the tip on batteries.. most have said GC2 batteries are fine.. which will have to do for the 1st year or two.. (that or the NAPA 8146 (225ah) or Rayovac GC125 (226ah)..)

The Rolls are out of my price point.. $811 each for the 6CS17.. and I'd need 4 to get to 24v.

So can you afford to replace the GC2 batteries thisa Summer? If you are really going to run Air Conditioner on solar using the batteries, they will not make it through summer. Treated with kid gloves GC2 batteries only have about 200 to 300 charge cycles in them. Abused by over discharging maybe 100 cycles. You might want to rethink this because you have been given bad information. Check the weight of all those batteries and compare it to the T-105RE which is in a GC2 case and weighs in at 69 pounds. That should tell you something.

[epsgunner]

Sunking

$1200 every 2 years (for 8 (6v) T105's = 440ah) seems better than $3200 right now..

The T-105 is 62 lbs.. I agree the T-105RE is only slightly more $ and a 2 yr warranty... which may be of interest.. but the Rolls is out..

I plan on running the A/C for 2 hours per day at the most.. which if I ran during peak time 1-3 or 2-4 I will still have max power coming into the panel set.. the A/C is rated at 550 watts AC.. (or 55 amps DC per hour)..

I did the math on another forum.. with everything based on that 52% eff # I will have 405.6 watts per hour coming into the system.. which is 40 amps DC.. if I am drawing 55 for the A/C unit.. the difference is only 15 amps per hour coming off the battery bank.. (which again will be 440ah).. I don't think 30-40 amps coming off a 440 ah bank will be too bad on it.. IMHO.. less than 10%..

[Sunking]

Sunking

$1200 every 2 years (for 8 (6v) T105's = 440ah) seems better than $3200 right now.

T-105's are not going to last 2 years. They only have 200 to 400 cycles in them. The T-105's cost you $113/Kwh. Rolls cost $140/Kwh so your math is off somewhere or looking at the wrong vendor or battery. The Rolls have a full 10 year warranty and will last 7 years.

[epsgunner]

T-105's are not going to last 2 years. They only have 200 to 400 cycles in them. The T-105's cost you $113/Kwh. Rolls cost $140/Kwh so your math is off somewhere or looking at the wrong vendor or battery. The Rolls have a full 10 year warranty and will last 7 years.

Maybe these 6v Rolls an S-460 350ah $326 or S-530 400ah.. $360. I may be able to justify them.. 7 year warranty with a 2 year replacement.. even though the AH works to the same or less as 4 of the T-105RE's you pointed me toward <<which I am fovoring at the moment with the 2 year warranty as well...

And did you note my SOUTHERN position?? I have 10 acres wide open and the panels will be on movable mounts..

[epsgunner]

For your budget you could get 4 of these
Shipping would be about $200. (get a quote)
this is 1100 watts. these are 72cell modules comparable to 2 of the 36 cell.
Almost 50% more wattage for about the same price.
These are grid tie modules minimum order is one.
Yingli is chinese but quality chinese.

http://www.civicsolar.com/product/yi...ts-solar-panel

Naptown.. thank you for pointing me back to them.. after the 190w idea seemed lost.. the 275's and 280's from Yingli look good at that price.. just waiting on the shipping quotes..

[Naptown]

Naptown.. thank you for pointing me back to them.. after the 190w idea seemed lost.. the 275's and 280's from Yingli look good at that price.. just waiting on the shipping quotes..

the increased wattage may allow you to get into float mode faster. Once in float during the summer you will have an overabundance of power from the panels. This may actually allow you to run the AC for an hour or two on a sunny day without going into the battery storage. ( note this may or may not actually happen it will depend on the day and the state of your batteries in the morning)