1. Penn State University
15
Installing Your Own Solar
Power System
Stand-Alone and Grid-Tied Systems
By: Chad Ryan Weiss, Ecenaz Asku, and Kevin Neil Neidlinger

2. 1
Fig. 1 - Power Panel
Main
Disconnect
Solar Panel Installations
The good thingaboutinstallingsolarpanelsisthatyoudon’t
necessarilyhave toshutoff powertoyourhome until the verylast
part that is,hookingitup. That beingsaid,safetydoescome first;so
that’swhere we’ll start.
Shuttingoffpower to a circuitor your entire home
In the UnitedStates,mosthomesare poweredbyone phase of a
three-phase 15kilovolt(kV) distributionfeeder(i.e.the powerline).
The powerto the house isfedviathree wiresfromthe service
transformer(xfm),twohotwiresat120 volts
each andone neutral wire. These three wires
are hookedupto the service entrance panel
(a.k.a.the powerpanel). See Fig.1
Most service entrance panelshave amainonor
off switch.
Flippingthisswitchwill turnoff all the powerto
your home. All of the otherswitchesare
attached
to individualcircuitsandcanbe shutoff
individually.
The arrow here ispointingtothe main disconnect
switch. Flippingthiswill turnoff the powertoyour
home.
Your home’selectrical systemisacompositionof manyindividual
electrical circuits servedthroughadedicatedcircuitbreaker (CB). A
CB is designedtoisolateordisconnectitsassociatedcircuitshould
there be any faultinthe circuit. CB’s vary inratings:10, 15 and 20
amps for120 voltsourcesand30 or 40 ampsfor 240 voltsources.
Safety First!!!
Whenever you areworking with
any electrical systembe sureto
followthe basic standard safety
procedures.
There are three key rules to
practicingelectrical safety:
1. Be sureyou understand
the basics of electricity,
circuitry,and your own
home’s wiringsystem;
2. Never work on any
electrically “live”circuit.
Be sureto shut off the
power and test that it’s
off.
 To test whether a circuit
is “live”or dead, justuse
a neon lightindicator so
that you don’t hurt
yourself.
3. Know the hazards and
risks of workingwith
electrical systems and
circuits.

3. 2
These switcheswillturnoff anyparticularcircuitof your choosing
and leave the restof the house untouched.
So now that we’ve coveredthe basicsof electrical safetyinyour
home,we can begin totalkabout installing,andgettingtoknow your
newsolarsystem.
Knowing Your System
A solar-basedsystemuses photovoltaic(PV) cellstoconvertlight
energyintoelectrical energythatcanbe storedor consumedon
demand.
About the system
2159 watt grid-tie PV systemusing10 PV panelsat215 watts.
Thingsto note
 Most commontype of solarPV system,
 Connectedtoelectrical grid  allowsthe use of solarenergy
+ electricityfromthe grid.
 Solarpanelssendthe excesselectricitybacktothe grid.
Pros:
 Lowestinitial cost(because thereisnoneedforbatteriesand
charge controller)
 Lowestongoingmaintenancecost(nobatteriestomaintain
and replace)
 Simplesttoinstall
 Most efficient(becausethere are lossesassociatedwith
chargingbatteries)
 You can start small and add(withsome limitations)
Cons:
 No powerwhen the gridisdown.
 Accessto the utilitypowergridisrequired.
System Components
 Solar Panels
These are “Photovoltaic”solar
panels which aremade up of
photovoltaic cells.Thesecells
absorb sunlightand convertit into
electric current.
 Charge Controller
These regulators control the
voltage going into the battery and
protect battery dischargeduring
night time, and it helps allow
more electric current flow when
the charge is low.In caseof over
charge, the controller terminates
the current.
 Batteries
Batteries arean essential partas
they store the energy that was
converted from sunlightinto
electricity.You will always need
batteries unless you are
connecting your panels to the
electric grid.These batteries can
be wired together to provide the
needed storage.
 Power Inverter
The power inverter converts direct
current power from the batteries
to alternatingpower. There are
two types; modified or pure sine
wave inverters.
 DC Disconnect
Only needed for a grid-tied
system. Itis used to turn off the
power connection to solar panels.

4. 3
PART 1 - INSTALLING YOUR GRID-TIED SOLAR SYSTEM
A/B. The Mount Design & Wiring the Trench
In orderto move ontothe installationof the equipment,
youshould:
 Buildthe mount
 Buildthe frames
 AdjustdimensionforPV system
 Setup undergroundwiring
 Install aluminumrails
Afterthe completionof these steps,before movingonto
installation,yourdesign shouldlooksimilartothat of
Figure2.
C. Installation of System Components
1. Before beginninginstallation,have the equipment
ready:
 PV panels
 Micro Inverters
 GroundingStraps(to ensure continuous
groundof rail splices)
2. Figure out the sequence of boltsandslide the bolt
headsintothe rail.
The Mount
Design ✓
Wiring the
Trench ✓
Installationof
system
Components
Wiring the
System
Figure 2. Rails are mounted,and the designis
ready for the panel installation.
Figure3.Top rail. Bolts are slidinto place.

5. 4
3. Sort out the hardware to connectmicro-inverterstothe
rail.
4. Mount the microinvertersstartingfromthe toprail:
 Mark the centerof each of the PV panels
 AC outputconnectorshouldbe towardsthe
junctionbox
5. Work your waydown the rail,insertthe inverters same
way.
6. Install a groundstrap across rail splices.
7. Clamptemporarywoodsupportto the frame alongthe
line of the bottomof the PV panels.
8.Once aligned,tightenthe nuttoholdthe panel in
position.
9. Once all the panelsare installed dothe final trim of the
railsto the length.
D. Wiring the System
1. Before proceeding,please refertothe safetywarning.
2. Wiringconnectionsforthe microinvertersystem(Referto
figure6).
PV array
Disconnect
Switch
Disconnect
Switch
Circuit Breaker
(leave off once
hooked up)
PV panels
micro-inverters
(connect to each
other & array
junction box)
Figure4.The inverterinstalled
Figure5.All the panelsare put into place.
SAFETY WARNING
The voltagesare extremelyhighand
potentiallylethal!
Even whenthe grid isoff, systemcan still
presenta seriousshock hazard!
If you don’t think you can learn how to do
this stepproperly,please hire an
electrician!

6. 5
3. All of these
componentsshouldbe
grounded:
 The PV panel frames
 The PV panel support
rails(including
groundbonding
across splicesinthe
rail)
 The micro-inverter
case grounds
 The PV array junction
box (if metal)
 The Disconnect
switchhousing(if
metal)
4. Wire the PV array junctionbox,whichisusedtoconnectthe firstmicro invertertothe wiringthat
goesto the house.
5. Obtaina disconnectswitch(local electrical supplierswill have them).Andwire the connections.
6. Install the newPV feedin circuitbreaker.
7. Wire the PV panelsandinverters:
 Plugthe DC leadsfromthe PV panel intothe twoDC inputleadsfromthe micro-inverter.
 Keepdoingthisforall inverters
 For the last one,plugmale cordfromlast invertertothe female cord
8. At thisstage,once you flipthe PV circuitbreakerandturn on the PV disconnectswitch,youshould
be able to readthe date fromthe EMU unit.
Figure6.Diagram of the micro-invertersystem
Figure7.Wiringof junction
box.
Figure8. Meter, house power
distribution panel, and the newPV
arraydisconnect switch.
Figure9.Last inverter inline. The
cap is screwedin over its input
connector.

7. 6
PART 2 – INSTALLING YOUR STAND-ALONE SYSTEM
Step 1: Planning and Preparation
 Make sure to do ample researchonthe specifications
of the systemthatyou’re tryingtoinstall. Thingsof
concernmay include:
o How muchpowerdo youconsume?
o How will yourlocationaffectthissystem?
o How muchelectricitycanbe generated?
o How muchwill thiscost?
o How longbefore yousee anysavings?
 Don’tforgetto add in the costsfor a backup charging
systemjustincase the batteriesare drained.Have a
backupgeneratorready.
*For this example, thehomeownersconsumeabout 24kWhoursannually and they receive about
4kWh/m2
/day,according to theirgeographiclocation specifications.Thesolarpanelsthey will be
utilizing use about20% of the sunlight’senergy to produceelectricity. They wish to becomeenergy
dependent.
Step 2: Purchasing the NecessaryEquipment
 SolarPanels
o Manufacturer: SunPower
o ID: SPR-X21-255
o Rating: 255
o PTC Rating: 241.70
o Density: 19.00
o Efficiency: 21.57
o Tier: 1
o Dimensions: 61” x 41”
 Batteries
o Type: FLA Batteries
o Volts: 12 V
o AmpHours: 357 Ah
o Temp: 60 F
o Discharge: 0.9
o Autonomy: 2 days
o System: 48 V
 Charge Controllers
o BatteryBank: 12 V
o Max Output: 60 A @ 12 V
o Max Input: 250 V
We will be installinga2.5 kW solar
powersystemusing 10 panels. The
goingprice is$4.00/W for a total price
of $10,000.00. The total dimensions
will come toaround12.4 square
meters.
For thissystem, withthese
specifications,we will needatotal of
12 batterieswired4inseries,3 in
parallel.Eachbatterycostsabout
$1,000.00 so the total will be
approximately$12,000.00 for batteries.
Seeingthatwe have 2.5 kW of solar
panel powerandour controllerscan
handle about720 W. We will need4
charge controllerseachcosting$610
for a total of about$2,440.00 to ensure
safe battery bankcharging.

8. 7
 Inverters
o Type: Magnum Energy
o Watts: 2800 W
o Input: 12 VDC
o Output: 120 VAC
o Form: Pure Sine Wave
 Other
o Circuitbreakers
o Tools& Wires
Step 3: Hooking It All Up
 For thissystem, the solarpanelswill be
mountedona rack andconnectedin
series,facingthe sun.
 We will be usingthiscircuitdiagramas
a guide to connectour system.The red
wires(orwhite) are positive,the black
wire are negative. (See Figure10.)
 The connectionbetweenthe inverter
and plugpointincludes:A live (RED)
wire,a neutral (BLACK) wire andthe
grounding(GREEN) wire.
 Be careful whenmakingthese
connectionsand make sure the
power is turned off!
 Do not cross wiresandmake sure to cut
all wirestoan appropriate lengthand
stripthe endswitha wire stripper.
1. Solar Panel Connections
 Connectthe wirestothe solarpanel.Letthe
redwire be connectedtothe positive terminal
and the blackwire to the negative terminal.
 Connectthe otherendof the redwire to the
inputof the firstcircuit breaker. Then,
connectthe otherendof the black wire to
the inputof the secondcircuitbreaker.
Thisinverterhasan inputthat matches
that of the batterybankand deliversan
outputthat isacceptedby mostloadsof
thishousehold. One inverterof thistype
shouldmeetthe house’sinstantaneous
powerandsurge requirements. One of
these costsabout$2,000.00 to buy.
Figure10. CircuitDiagram
Figure11. Solar Panel Junction Box

9. 8
2. Circuit Breaker Connections
 Connectthe outputof the first circuit
breakerto anotherredwire andthe
outputof the secondcircuitbreaker
to anotherblackwire.
 Connectthese newlyconnectedred
and blackwirestothe positive and
negative terminalsof the charge
controller.
 Tightenthe screwsof the terminals
usinga screwdriver.
3. Charge ControllerConnections
 Connecta red wire tothe outputof
the charge controller’s positive
terminal andconnectthisto the input
of the nextcharge controller.(Parallel
Connection)
 Thenconnecta blackwire tothe
outputof the charge controller’s
negative terminalandconnectthisto
the negative inputterminalof the
nextcharge controller.(Parallel
Connection)
 Make these connections untilall charge controllersare hookedup. Thenconnectthe final
outputof the charge controllerbank’spositiveandnegativeterminalstothe positiveand
negative terminalsof the batterybank.
4. Battery Connections
 To connectin series,connectredtoblackand blackto red.To connect inparallel,connect
redto red and blackto black. If youaren’tsure how thisisdone,hire anelectrician.
5. InverterConnections
 From the batterybank,connectthe red wire fromthe endingpositive terminal tothe
positive inputterminal of the inverter. Connectthe blackwire fromthe negativeterminal of
the batteryto the negative inputterminalof the inverter.
Figure12. CircuitBreaker Connection (Below)
Figure13. Parallel ChargeControllers (Below)
Figure14. Battery to Inverter Connection

10. 9
6. Power MeterConnections
 The outputof the inverterhasthree terminals:Live,Neutral andGround.Connectthe
powerconsumptionmetertothe three terminalsof the inverter’soutput.
 Finally,plugthe outputof the powermetertothe plugpointconnections.
Step 4: Testing the System
 If you have a smart meter,youwill
know that the systemisworking
because itwill show youthe wattsthat
are beinggenerated. Youcan always
plugina lightbulbtosee if itisworking
also.
 If the lightbulborsmartmeterindicates
that the systemisnot working,goback
and make sure that all yourwiresare
straightand redothe calculationsto
ensure thatyouhaven’toverloadedany
circuits.
References
 http://www.homepower.com/articles/solar-electricity/design-installation/designing-stand-
alone-pv-system/page/0/5?v=print
 http://www.iflscience.com/environment/here-s-roundmap-get-us-run-100-renewable-energy-
2050
 http://www.instructables.com/id/Apartment-Solar-System/?ALLSTEPS
 http://www.instructables.com/id/Solar-Power-System/?ALLSTEPS
 http://www.solardesigntool.com/components/module-panel-solar/Sunpower/2228/SPR-X21-
255/specification-data-sheet.html
 http://solarsimplified.org/connecting-to-the-grid/ongrid-offgrid
 http://www.wholesalesolar.com/charge-controllers
 http://www.wholesalesolar.com/deep-cycle-solar-batteries
 http://www.wholesalesolar.com/power-inverters
 https://www.youtube.com/watch?v=GnZFi9CzF9Q
Figure15. Smart Power Meter