7000watts per day solar system

System

I am totally new at this, but thats the figure I came up with for a solar system. I've had bids for both 24v and 48v ( 10- 200w kyoceras ) Outback FW500 with a VFX 3524 and 12 crown CR-395's plus various components for the 24v system to ( 14 solarworld 175w ) Outback FW500 with VFX 3648 and 24 rolls S-460's plus various components for the 48v system. Don't know which way to go, all I want is it to work with less maintenance. My backup will be a 8kw diesel generator 1800 rpms, Northern lights NL753 with auto satart capability. I'd really appreciate your feedback as my family is living on the property in a tuna can travel trailer while the 1200 sq. ft. house is getting done. I would probably house the batteries, outback and generator in a shed. Water is coming from two 2500gal. water tanks. House will have propane heat (until woodstove is in ), propane stove, propane dryer, electric fridge. I'm out of state due to job and parents health issues. Thanks alot!

BB.

Re: 7000watts per day solar system

Where will the system be installed? Do you have good sun or not?

You can look at these two links for how much sun you will get in your area. (pdf files, calculator based on PDF file information).

And what is the chance of getting utility power vs going completely off-grid. A grid tied system + utility power will still be "relatively green and allow you to reduce upward price pressures over the next couple decades) vs going completely off grid and having your base cost for power much higher because of the extra hardware, batteries+maintenance, generator+fuel, etc.).

Also, you really need to know how much power you will be using. Getting a kWhr meter (like the ~$30 kill-a-watt) and watching your current monthly power bills will help a lot.

Also you will want to pay attention to how much power you use in what months/seasons. If you use power in the summer and have good solar--that is a plus. If you use more power in the winter and have lots of clouds--then you will be running the generator a lot--and it is probably not worth sizing the solar array for winter use and have it way over$ize for summer.

In a reasonably sunny area, your grid tied system will be in the range of $0.25 per kWhr... A similar system sized off grid system will probably cost you in the range of $1.00+ per kWhr (numbers are very rough estimates and in areas with less than good sun, they can be much higher).

7kWhrs (I assume that is what you mean) a day works out to 210 kWhrs per month. Power at $0.10 per kWhr--that is ~$21 per month. An off grid system, that will be $210+ per month.

200kWhrs per month is not a lot of power for a home that does not have a/c and uses natural gas/propane/oil for cooking and heating. However, it is possible to get down to 100 kWhrs per month for people that really design and live the "off grid lifestyle".

-Bill

crewzer

Re: 7000watts per day solar system

Mark,

Tell us a bit more about your system quotes and location. For example, which charge controller was proposed (i.e., OutBack MX60), and where are you located in AZ (Flagstaff? Phoenix? Tuscon?)?

The 2000 W array may well be a bit too large for the 24 V system (assuming a 60 A controller). Ambient temperatures may affect your PV array configuration, so location can be an important design consideration.

Also, while the OutBack FW500 is a nice product and will work with just one inverter, it's really intended for two inverters. The MidNite Solar E-Panel might be a mode cost-effective solution for a single inverter.

See: http://www.midnitesolar.com/E-Panels%20Explained.pdf

More later,
Jim / crewzer

niel

Re: 7000watts per day solar system

i'm seeing a big difference between the wattage of each pv system. i know the pvs have differing vmps and we can't comment unless we'd have more info on how it was to be setup specifically.
the kyoceras are a 2kw system and the solarworlds are a 2.45kw system.
without looking it all up be sure each system will charge each battery system properly. if below a 5% charge rate that's no good and would do better with a higher %.

System2

Re: 7000watts per day solar system

I'm located 50 miles north of Prescott at 5700ft. The contoller on the both is a mx60. The 48v system states 2450 peak watts DC, 7400WH/day

niel

Re: 7000watts per day solar system

ok i'll ask straight up. why not add 2 more kc200 pvs for a 2.4kw system rather than the 10 pvs for kyocera you listed? how were the pvs to be arranged, ie how many in series strings by how many strings paralleled? i'm sure the vmp is involved as a reason, but i'd like to hear from you on the specific layout for each pv system.

Solar Guppy

Re: 7000watts per day solar system

Since this is a whole house system, go 48V for sure on the battery bank

System2

Re: 7000watts per day solar system

24v layout (10 )kyocera 200w panels,1 mx60,1polemount for panels, 1 fw-aca, 1fw-dca, 1fw- mp, 1 VFX 3524, 1fw500-ac,1 fw500-dc 1 fw-ccb(mounting bracket), 1 fw-iob-d-120(dual inverter input-output bypass for fw500-120/240vac output 60 amp,14.4kw,1 obb-60-125vd(dc breaker-60amp150vdc),1 obb-250-125v(dc breaker-250 amp 125 vdc, 2 ob-rts outback remote temperature sensor,1 mate ,12- cr-395 batteries, 5 30ft mc3 cable,1 10x10 low voltage combiner box 125volts max , 5 ab-15 pv array breaker, 12 each gbl4-dbt solar grounding lug direct burial,14-4 CU/AL tin plated,9 #2/0x12 " battery cables with 3/8" lugs, also 2 at 18", and 2 black at 18", job materials concrete misc conduit, locknuts etc. $20,500 w/o labor. The 48v system is (14 ) sw175 solar world modules, outback vfx3648 inverter, outback aca and dca adapter kit,fw-mp mounting plate fw500-dc enclosure,fw500-ac enclosure, input/output bypass, (2) obb-60 array and controller breakers, obb-175/250a 125dc breaker, mate inverter display and controller,(24) rolls s-460 batteries, trimetric amp hour meter, TM-48 48v adapter, (2) lightning arrestors, outback mx-60 mppt charge controller, rts temp sensor for controller, outback pspv w/breakers, assorted inverter cables, battery interconnects,hardware,wire,etc, plus pole mounts. $27,000 w/o labor.. I just don't want to get hosed with the wrong system. I have no idea how there hooking it up, my experience has been (before I left Az) was to hook up (3) shell 110-12p to 8 trojan t-105's with an auto charger from sears and an old gas generator with a 700 watt inverter for the tuna can trailer to power the tv, heat tape on the water pipe, water pump from the holding tanks, and the propane powered stove,fridge and furnace.

crewzer

Re: 7000watts per day solar system

Mark,

On paper, either of these systems should be able to supply 7 kWh/day in the Prescott area, even in December (array tilt = latitude + 15 drgrees). But. I think both proposals contain significant problems.

24v layout (10 )kyocera 200w panels,1 mx60,1polemount for panels, 1 fw-aca, 1fw-dca, 1fw- mp, 1 VFX 3524, 1fw500-ac,1 fw500-dc 1 fw-ccb(mounting bracket), 1 fw-iob-d-120(dual inverter input-output bypass for fw500-120/240vac output 60 amp,14.4kw,1 obb-60-125vd(dc breaker-60amp150vdc),1 obb-250-125v(dc breaker-250 amp 125 vdc, 2 ob-rts outback remote temperature sensor,1 mate ,12- cr-395 batteries, 5 30ft mc3 cable,1 10x10 low voltage combiner box 125volts max , 5 ab-15 pv array breaker, 12 each gbl4-dbt solar grounding lug direct burial,14-4 CU/AL tin plated,9 #2/0x12 " battery cables with 3/8" lugs, also 2 at 18", and 2 black at 18", job materials concrete misc conduit, locknuts etc. $20,500 w/o labor.

Problems:

(1) This quote suggests a 10 module x 200 W / module = 2,000 W array for the MX60. The MX60’s official limit for a 24 V system is between 1,500 W and 1,800 W, depending on which document and specs you consider.

See: http://www.outbackpower.com/pdfs_spec/MX60_a.pdf
And: http://www.outbackpower.com/pdfs_spec/OutBackCatalog.pdf

Frankly, the MX60 should able to handle a 2,000 W STC array under most circumstances, as the array will rarely deliver 2,000 W. But, it will deliver than much power – and even more – under certain circumstances, such as a cold, partially cloudy say, or a cold, sunny day with snow on the ground. In these cases, the controller’s default setting will limit output power to ~62 A.

However, if your system will require an inspection and permit, the inspector may fail it due to this specification mis-match.

(2) This system includes one Mate and two RTS’. The plan is to use the Mate and one RTX for the inverter, and the second RTS for the MX60. This will work, but the mate won’t be able to communicate with the MX60. A better configuration would be the Mate, one RTS, and a Hub-4.

(3) The Midnite Solar MNPV-6 combiner would be smaller and cheaper than the 10 x 10 low-voltage combiner.

(4) The FW-500 equipment is overkill for a single inverter. Check out the MidNite Solar E-panel instead.

The 48v system is (14 ) sw175 solar world modules, outback vfx3648 inverter, outback aca and dca adapter kit,fw-mp mounting plate fw500-dc enclosure,fw500-ac enclosure, input/output bypass, (2) obb-60 array and controller breakers, obb-175/250a 125dc breaker, mate inverter display and controller,(24) rolls s-460 batteries, trimetric amp hour meter, TM-48 48v adapter, (2) lightning arrestors, outback mx-60 mppt charge controller, rts temp sensor for controller, outback pspv w/breakers, assorted inverter cables, battery interconnects,hardware,wire,etc, plus pole mounts. $27,000 w/o labor..

This system will have problems. The likely planned array configuration is 2 x 7. However, the voltage from this “48 V” array (~71.6 Vmp STC) will likely be too low in the summer in your location (~57 V or so after drops in the wiring, breakers, and MX60 controller)) to properly charge the batteries (~58.4 V required to get to absorb, ~62 V required to get to EQ).

I don’t like “48 V / 48 V” system in hot locations. A “60 V / 48 V” approach is much better. Other problems with the Mate, RTS’ and FW-500 enclosure remain as per the 24 V system.

The quote for 24 Rolls S-460 batteries in a 48 V configuration suggests an 8 x 3 configuration rated at 48 V x 1,050 Ah. A 5% charge current would be ~50 A. The 2,450 W STC array can deliver ~36 A on a typical day, or about 3.4% of capacity. I think that’s a bit on the low side.

I’d reject both systems.

HTH,
Jim / crewzer

mike95490

Re: 7000watts per day solar system

I like the 48V system, if you can wire your array to provide ample hot weather charging voltage. 48V feeding the inverters is less loss in the wires.

Here's a great writeup on how to properly wire your battery bank (diagonally)
http://www.smartgauge.co.uk/batt_con.html

niel

Re: 7000watts per day solar system

jim,
i was thinking because the kc200 has a 26v vmp that 3 in series should give that extra kick for the hot climates without going real high like the solarworld pvs having a vmp of 35v x 3. 2 solarworlds in series would be about the standard of about 70v and less during high heat. the 3 kc200 pvs would be about 78v so this would overcome the heat loss due to climate and keep efficiencies higher due to not being in the 100v area like 3 solarworlds would be at less efficiency for the controller. this could be 4 paralleled strings of 3 seriesed kc200 pvs and allow the mx60 to be within wattage spec too operating at 48v output. that means 12 kc200 pvs and a system of 2.4kw.
for batteries this 2.4kw system would be good to about 608ah @48v in batteries for about a 5% charge rate. if more battery power is to be needed then more strings of 3 kc200s would be needed to properly charge them of which up to 2 more strings of 3 in series could be added to the mx60 as it is stock for 48v systems.

crewzer

Re: 7000watts per day solar system

OK. Since Mark needs a system with an array rated at >2,000 W STC, and has been quoted a 60 A charge controller, let’s pass on the 24 V battery system.

A 2,400 W array configured from 12 KC200’s should usually work. However, with average summer temps in Ash Fork, AZ, of ~90 F, and a record high temp of 110 F, I still think that an array with a rated Vmp of 26.3 V x 3 = 78.9 V could be troublesome in the summer. Ambient temperature of 104 F (40 C) could drive the array temp to ~75 C. This is about 50 C above STC spec, so a voltage reduction of ~25% could be expected. 59 V would work for driving the batteries to the absorption voltage, but not to the EQ voltage.

I would recommend caution in considering a 3,600 W STC array for the 48 V system. Although the MX60 could probably handle such an array, it is in technical violation of the MX60 specs.

I just don't see the point of starting from scratch and spec'ing a system that could be dicey.

At the other end of the temperature scale, Ash Fork’s average low winter temp is down to the low 20’s (F), with records as low as -18 F. Using the NEC 690-7 temp correction factor of 117% and the MX60’s operational voltage limit of ~141 V, the STC Voc limit is ~120 V, or ~40 V per module in a 3-module series.

Here’s a solution that will work:

(a) 12 each Sharp ND-200-U1 (Vmp = 28.5 V, Voc = 35.5 V) wired 3 / series and 4 parallel strings (2,400 W STC). Could add one string for 3,000 W STC total.
(b) 1 ea Midnite Solar MNPV-6 combiner
(c) 1 each MX60 controller
(d) 1 each Hub-4
(e) 1 each Mate
(f) 1 each RTS
(g) 1 each VFX3648
(h) 1 each Midnite Solar E-panel
(i) Misc wire, breakers, arrestors, etc.
(j) 48 V battery bank of ~600 Ah to 700 Ah
(k) Battery box(es) with vent

Another PV solution would be 20 each Kyocera KC-130’s wires 5/series and 4 parallel strings (2,600 W STC).

Note that battery performance will suffer in the winter in an unheated shed.

[FONT=&quot]HTH,
Jim / crewzer
[/FONT]

Solar Guppy

Re: 7000watts per day solar system

Well, since this is offgird

http://www.sunelec.com/

The Sun 170's , vmp of 25.3 , so an array of 4 x 4 , 2720 watts and lower cost than all the other suggestions @ 3.24 / watt.

More watts, lower cost and not as close to the edge on cold weather on the charger.

System2

Re: 7000watts per day solar system

I really appreciate your wisdom and help, I'll look somewhere else, maybe southwest wind, I do have some good wind in the winter, thanks again!

mike95490

Re: 7000watts per day solar system

AZ Mark wrote: »

I really appreciate your wisdom and help, I'll look somewhere else, maybe southwest wind, I do have some good wind in the winter, thanks again!

Gotta love the draw of the wind. Let us know if you discover any "consumer" owner of a wind gennie, that is happy. Only the hobbiests that build one seem to get output.

Beware.

crewzer

Re: 7000watts per day solar system

The Sun (Evergreen Spruce) 170's Voc is 32.4 V. Four in series would be 129.6 V. Factoring in the NEC 690-7 117% TCF for the Ash Fork area puts the Voc at 151.6 V.

This value exceeds the operational voltage limit for the MX60 (~141 V), and it also exceeds the absolute voltage rating for the breakers and the MX60 (150 V). Not a good suggestion, in my view.

However, the Sun 190's in series strings of three might be a good alternative. Their Vmp (26.7 V STC each, 80.1 V for the string) would be high enough for all applications except EQ on a very hot day. That's easy enough to "reschedule". Voc (32.8 V STC each, 98.4 V STC for the string, 115,1 V Voc with NEC 117% TCF) is low enough to not be a problem for the breakers and controller in cold weather.

Twelve of these modules wired 3 x 4 would be good for 2,280 W STC, and fifteen of 'em would be good for 2,850 W STC. The MX60 can handle either either.

HTH,
Jim / crewzer

machineman

Re: 7000watts per day solar system

Here's a nice calculator that can help estimate the max - min temperature influence on voltage from various panel arrangements. The site is Xantrex but I think the numbers are generic and depend on what panel you select.

http://www.xantrex.com/support/xwsizing/disclaimer.aspx