7000watts per day solar system

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

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