SETTING UP A SOLAR PANEL/BATTERY AND 12 …

1 The Specialists in LIGHT & POWER on the MoveSoterion Pty Ltd 4/37 Rushdale Street, Knoxfield 3180 Tel: (03) 9764 9769 Fax: (03) 9764 9738 TIPS and TECHNIQUES: SOLAR PANEL DIYby George LinardosSETTING UP A SOLAR PANEL/BATTERYAND 12 VOLT FRIDGE SYSTEM The milk s gone off, everything frozenhas thawed and you guys have beenout fishing all day! Those words clearly summarized myfirst attempt in going camping with a12v fridge and SOLAR panel wife was clearly not impressed andto be honest, that camping holiday wasa disaster. I was ill-informed, ill-equipped and I spent most of theholiday shuttling backwards andforwards to friends with powered siteslugging heavy batteries and setup I had simply did not work-even under the best my return to Melbourne I wasdetermined to investigate this topicfurther and subsequently spent manyhours talking to manufacturers andsuppliers of SOLAR panels , fridges has not made me an expert onthe subject but with some of my newfound technical knowledge behind meand ten or so years camping for amonth each year on an un-poweredsite and conversing with dozens ofother campers using SOLAR /12v fridgecombinations I may be able to help youavoid my initial remember a doctor friend who oncesaid that there is a point in medicinewhere it s no longer a science but anart form!

2 To a certain degree the samecan be said about this subject. We cancontrol the technical aspect but wecan t control the most importantelement and that is IMPORTANTF irst determine whether you intend touse the fridge occasionally on a shortterm stay. long weekends [3-4 days],or for longer stays of a week or TERM[3-4 days]A 50Lt to 80Lt fridge will require a 100wor preferably a 120w SOLAR panel and a100 AmpHr battery as a TERM [1 week or more]A 50Lt to 80Lt fridge will require two 80wsolar panels and sufficient batteries tohold 340 AmpHrs as a may argue with the above figureshowever as I mentioned before we can tcontrol the sunlight, its duration or clarityand we are preparing for the worst casescenario not just hoping for the SOLAR PanelThe SOLAR panel simply harnesses thesunlight, converts it into energy or powerand stores it into a battery or RegulatorThe regulator limits the amount of powerthe SOLAR panel is putting into thebatteries. Its function is to stop the solarpanel from overcharging and thereforedamaging the BatteryThe battery is the store room of power.

3 Itreceives power from the SOLAR panel,stores it and disperses it to the fridge we are talking about portable fridgeswhich work on 12v power. Most work on240v as well but that does not concern us forthe purposes of this smart fridges are designed to work oneither 12 or 24v and will automatically adjustto suit. The Waeco-C-F-80 is one ofthem. However all of our calculations andset-ups will be based on 12V systems. Duty cycle , when referring to the fridge,means what % of the the time the motor of thefridge is working over a 24hr. like your fridge at home the motor onlyworks in order to keep the contents at thedesired temperature which you have *the bigger the SOLAR panel themore power will go into the battery . Thebigger the battery the more power it willstore. The bigger the fridge the morepower it will draw from the Specialists in LIGHT & POWER on the MoveSoterion Pty Ltd 4/37 Rushdale Street, Knoxfield 3180 Tel: (03) 9764 9769 Fax: (03) 9764 9738 TIPS and TECHNIQUES: SOLAR PANEL DIYby George LinardosCHOOSING SOLAR PANELSThe size and power consumption of yourfridge will determine the size [measured inwatts] of your SOLAR panel or multiplepanels and the size of your battery orbatteries.

4 Beware,there are no short cutshere. SOLAR panels are not order to achieve their maximum powerout- put they need direct sunlight at 90degrees, clear non-haze skies, and evendust on them can prevent achievingmaximum performance. In other wordsconditions must be ideal and very oftenthey are a rule of thumb remember this. A 100 Wsolar panel will deliver amaximum of 6 amps per hour into yourbattery under perfect conditions. Since weonly count the hours of sunlight [sunlight before or after isconsidered too weak] the absolutemaximum or peak power we canSolar panels come in different sizes bothin dimensions and performance rated polycrystalline 12v SOLAR panels [theyare the ones featured in these photos] arecompact, powerful and contrary to popularbelief extremely tough. They will withstandconsiderable force and have been knownCHOOSING YOUR BATTERIESI do not intend to delve too deeply intothis area. There are enough claims,counter claims and a plethora of technicalinformation to warrant a separate s keep it as simple as possible.

5 Themain things you need to know is howmuch power the battery will hold[measured in amps], how many times canrecharge it [described as cycles ] and itsSo you walk into the battery shop and aska simple question like How many ampsis this battery mate? and the salesmanreplies 800 cold crank . Now that s great!We are working with SOLAR panels inamps, our fridge s drain on power ismeasured in amps and all of a suddenwe ve got cranks to confuse us totally. Itreminds me of that commercial I justThey tell me there s no formula to convert cranks to amps so if the amp rating isnot stamped on the battery , don t buy preferred batteries for this applicationare called deep cycle . They are sealed[no spillage of acids] lead acid batterieswith thick plates and can withstand manycharges and discharges. These are whatmost people use with their 12v be aware that they areHeavy .A 100amp deep cycle batteryweighs 33kg. Once you set them up theystay there. There is no maintenancerequired apart from regular YOUR REGULATORSome SOLAR panels come with theregulator already attached and wired toconnect directly to your battery .

6 In theevent that your SOLAR panel doesnot ,then you must buy a regulator to formula is simple. Always choose aregulator with an amp rating greater thanthat of your SOLAR panel or SOLAR panelscombined, if you choose to use oneregulator for both. For example a solarpanel producing 6amps will require a10amp regulator. A SOLAR panelproducing 3 amps will require a 5 prevent the battery fromovercharge and they also preventcurrent flowing backwards from thebattery to. the other choice you may wish toconsider is buying an up-market regulator with automatic LCD regulators [ such as the onefeatured here] actually show you howmany amps your panel is delivering and tthe charge state of your battery . Theread-out moves automatically andcontinuously from one reading toanother. You always know how muchpower is going into your battery -unfortunately they don t show how muchis going latter we have to calculate usingsome information we know and someguess work and some guess survive when hail storms havedestroyed roof tiles.

7 These panels areavailable in many sizes and powerratings. When choosing your panelsdetermine whether you will fix thempermanently to the roof of your van orwhether they will be free- SOLAR panels say 80watt or moreare cumbersome and heavy. You maywish to consider the folding type [shownabove] particularly if you are going to usethe free- standing other type of SOLAR panel is called amorphous . In my opinion they are notRemember also that a battery should notas a rule of thumb be drained more than50% of its capacity. Sealed lead acidbatteries like to be kept at full or close tofull stored, unused battery will continue togradually discharge without havinganything drawing on its power soremember to re-charge batteries everythree months or Specialists in LIGHT & POWER on the MoveSoterion Pty Ltd 4/37 Rushdale Street, Knoxfield 3180 Tel: (03) 9764 9769 Fax: (03) 9764 9738 TIPS and TECHNIQUES: SOLAR PANEL DIYby George LinardosINSTALLING A SOLAR PANELFOR A 12 VOLT FRIDGE SYSTEMThe first decision you have to make iswhether you will fix your panelspermanently to the roof of your van ormotor home or whether they will be free-standing.

8 There are advantages anddisadvantages with either roof-top SOLAR panels don t presentstorage problems. However they cannotpossibly face the sun at the optimumangle of 90 degrees. Also in the hotsummer months most people choose tocamp in the shade therefore furtherreducing the SOLAR panel s the other hand free-standing solarpanels can be moved to face the sunwhenever possible and within reason beset up away from your shady campingspot. Storage however now becomes you have consider the amount ofwires and cables which you will havearound your campsite as well as thesecurity factor re choice was easy as my soft topcamper trailer left me only with the free-standing is shown in these pages is a freestanding SOLAR panel/12v fridge/batterycombination as I would use. There aremany combinations of SOLAR panelsbatteries and fridges. Each is determinedby the factors that I mentioned earlier. Iwill not go into dual battery car systems,wind generators and other hybrid back-up can use the following calculationsprovided by Peter Israel from Solarchargein Melbourne to determine your ownneeds and set up average, the 80W SOLAR panel [twinfolding 40W] sitting flat on your roof in fullsun will put out about out about 5 PeakSun hour 5 [amps in full sun] x 5 PSE=25Ah aday.

9 The same SOLAR panel in a free-standing configuration and shifted a fewtimes a day to keep aiming at the sun willdeliver closer to 40 amp hrs [note thesignificant difference in flat mounted vsfree-standing movable panels !] Note alsothat Peter is counting only 5 hours of suneach day whereas others count on , if I am using two 80 wattfolding SOLAR panels I can expect [intheory] around 80Ah of power to bedelivered to my batteries If I attach to twox 100amp batteries connected in parallel[see photo] I have one 200Ah battery . Isthis enough? Well that depends on whatappliances we are running at the I have chosen the large Waeco CF-80 I know that it draws 4 amps on averageand a total of 62amps over a 24 hourperiod where the surrounding temperatureranges 24 hour period where thesurrounding temperature ranges from 15to 55 degrees Celsius [from the tests donein the Australian 4WD Monthly]. Now wehave to be careful here as the amount ofpower a fridge draws depends on manyvariables such as the contents, theambient temperature around the fridge,the cold SETTING , whether or not it is seton freezer mode, how many times it isThe duty cycle of the fridge iscalculated at around 50%.

10 All of theabove mentioned variables can changethis so some times the draw will be lessand at other times we are guided by experience [ourown and others] some facts and someguess work and this is where sciencestarts to become an art at it this way if the fridge drawsless than the figures quoted here,consider it a bonus. Always work on theworst case two 80w SOLAR panels will deliver atbest 80 Amp hrs per day. My fridge willdraw 60amps per day and I have 100amps in reserve in my batteries. I itseems that in theory I will have plenty ofpower. In reality I might just make it withplenty of clear blue skies! The panelswill rarely deliver their full power, therewill be power losses in the cables andconnections and anyone who thinkscampers spend their holidays movingpanels around all day just hasn t beencamping! [with all due respect to thearmchair experts ].Why have I got only 100amphrs and not200? Because you should never flattenbatteries less than 50% of their capacityapprox recommends at least 340amps inbatteries for a rainy day pardon thepun.