Solar Grid-Tie Battery Backup System

System Preview Video for Hans Kaiser, Central FL:
The vast majority of renewable energy systems installed today are direct grid tie. Direct grid tie systems simply convert the DC of wind, solar or hydro to AC power and feed power back to the main panel to slow down or spin back your meter. Although more efficient, when the grid power fails on a direct grid tie system, the user has NO POWER. This system in this video utilzes a hybrid grid tie with battery backup inverter/charger. (Outback GTVFX & Xantrex XW are the only 2 on the market) The solar & wind will charge the batteries, when the batteries are full, excess power generated slows down the utility meter or spins it backwards. In the event of a grid failure, solar and wind power is still usable & battery backup will automatically take over until the grid power is restored. The only additional cost is about $900 plus the batteries & cables. If you wanted to retrofit a direct grid tie system to be compatible with batteries will require a new inverter/charger ($2,000), a charge controller, and a massive PV array rewire. Or you can drop $5500 for the "Sunny Island" inverter that will take in AC power from an existing grid-tie only inverter, then connect to batteries. The Sunny Island is the easiest retro-fit for existing grid-tie PV and the only option for "SunPower" brand positive ground PV panels. If you want juice when the utility fails, purchase this (outback) system (or an XW) from the start. Please note: If you'd like to use a generator or require 240VAC/60Hz the XW is likely a better choice. These systems ARE eligible for (US) federal incentives (30+%), and most (US) state incentives. My price estimates are for high quality US or Canadian made products that will qualify for incentives, meet the National Electric Code, and be accepted (by law) by your utility provider. If you have more questions or even a bid, email me!

Category:

Science & Technology

Tags:

• Backup Power
• Renewable
• Renewable Energy
• Solar
• Wind
• Hydro
• Grid Tie
• battery backup
• backup power source
• sell back
• power
• BPS
• battery backup system
• Solar PV
• green
• green power
• electronics

[apaulanarius]

What is the cost of this system that you built for Hans? Just a ballpark please. This set up is so nice and clean. I currently have 12 volt solar and wind. What is the advantage for 24 or 36 volt systems?

[theoriginalswendaddy]

3. Features- From overall output (more watts), abundant surge capabiltiy, remote monitoring, an ac charger, grid- sellback, and quality are far more common features on inverters that have DC voltages at 24 or 48VDC.

Long story short, Spend a little more upfront & you'll have a longer lasting system that will do more of what you want, expand easier, and cost less over time.

[bykashka75]

@theoriginalswendaddy how much this system cost? whats the output usually AC power

[theoriginalswendaddy]

@bykashka75 This system would run around $10K for the inverter & distribution panel, around $1000-4000 for the batteries. Solar PV cost will depend on your budget, but would max out at 6kW or $36K worth of panels, racking, etc.. 

[theoriginalswendaddy]

@bykashka75 @bykashka75 -Keep in mind there are some lower cost solutions (Xantrex XW about $9400 with inverter & 8 batteries @ Backup Power Source Inc. and the US Federal tax incentive will reduce 30% of the cost. If you're overseas, the payback could be even faster when compared to utility rate.

[theoriginalswendaddy]

@Oppland29 I sell the cables with MC4 or H4 ends in various lengths (NEC Code compliant). 6ft=$20, 15ft=@26, 30ft=$38, 50ft=$44, 100ft=$75. (5/11/11) Basically, one end has a male, the opposite end has a female. Buy the length twice your distance, then cut in half. One end screws into a breaker or bus, then the opposite end interlocks with the corresponding male or female end. 507 227 2923 -Mike

[theoriginalswendaddy]

@Oppland29 A 10AWG (maybe 12) is fine for bringing the panel or series of panel to the combiner. The wires from the combiner down to your controller (actually to a breaker 1st) is sized determined by the DC voltage & the distance to the breaker/controller. An MPPT system may be sending 130V down the line requiring a smaller gauge than a PWM system sending only 12V to the controller, requiring a big 'ol 2AWG. If I were to blindly give you a gauge for rooftop to basement, I'd say 6AWG.

[theoriginalswendaddy]

2. Charge Controller Space, Buy an MPPT charge controller- It allows you to maximize solar harvest and feed a higher voltage to a lower voltage battery bank, and easlisy deviate away from 12V PV panels. The MidNite 150 Controller will let you feed 150V at 750W of Solar PV to a 12V battery bank, or feed 175V at 1500W of Solar PV to a 24V batt. bank, or feed 200V at 3000W to a 48V batt. bank. In other words.. have 3 $850 controllers at 12V, or 1 controller for 48V.

[theoriginalswendaddy]

@ Apaulanarius: The inverter(s) system (& distribution panel) ran about $8K, and another $2500 in batteries & cabling.

It's better to use 24 or 48V is for a couple of reasons.

(skip 36V, even for your golf cart, it's an industry oddball)

1. Battery Bank, you should only make 4 parallel connection before using a busbar for equalized charging & discharging. Larger voltages allow more series connections. Four 12V in one series = 48V (you can still make 4 parallel connections)

[cjhouts]

Could you please contact me as i have a few questions about my project. You can email me @ alter-ecoenergies@charter.net