Portable, fixed solar panels, lithium vs AGM batteries
If you’re into camping, caravanning and the great outdoors, you’d be well aware of the need to power up appliances such as fridges or devices like laptops, torches or general recharging especially when staying away for extended periods of time. Sure, you could carry a spare car battery and use this for as long as it will power your fridge or lighting but over a day or so, it’ll go flat and this is not advisable as you’ll ruin your lead acid battery by taking it below 50% charge. This is where solar panels come into play. A folding solar panel kit rated to around 120 watt will recharge most batteries through the day while at the same time, running your fridge and keeping your food and drinks fresh and cold. Our SolarKing 120 watt folding solar panel kit for camping comes ready to connect to your battery and includes a solar charger as well as a USB charging point so you can even recharge your USB devices such as your phone. Keep in mind, you’ll need to calculate what’s going out of your battery (consumption amps per hour) and what’s coming into your battery (charge amps per hour). You’ll also need to take into consideration the fact that you’re only getting input charge to your battery from your solar panel while there is sunlight but you’re appliances are still sucking out power day and night. The basics are :
Appliances/devices consumption in amps per hour (A/H) x running time per day (for a fridge this would most likely be 24 hrs) = total power consumption. For instance a small fridge requires 2 amps per hour so 48 amps per day. A 120 watt solar panel will charge your battery at the rate of approximately 5 – 6 amps per hour x sunlight hours. For this example let’s say 8 hours. So charge into the battery will equal around 44 amps (at average 5.5A/H). This would mean that our camping lead acid battery rated at 100 amps would sustain charge for around 10 days. Why 10 days ? We wouldn’t want to take a lead acid battery down any less that 60% charge and we’re losing 4 amps per day of charge as we’re using 48 amps but only replenishing 44 amps. So on the 1st day we’re down to 96 AMPS of battery power available, 92A on the 2nd , 88A on the 3rd , 84A on the 4th, 80A on the 5th, 76A on the 6th, 72A on the 7th, 68A on the 8th, 64A on the 9th, 60A on the 10th. This is not a real life situation as there are many variables such as weather and compressor function of the fridge, ambient temperature etc but it gives you a general idea. What a difference a small solar panel can make. We go from having a near to flat battery in one day as opposed to low charge in 10 days and all for free from the power of the sun and the miracle of a solar cell ! The above scenario is massively improved if a lithium battery were to be used with increases of three fold possible.
Based in Melbourne, SolarKing distribute their products to dealers throughout Australia including Melbourne, Sydney, Adelaide, Perth, Brisbane, Darwin and throughout the Sunshine Coast and Satplus are a premium distributor of these quality folding solar panel arrays.
The 120 watt folding solar kit comes in a carry bag and comprises of two 60 watt solar panels hinged together and wired to a built in MPPT regulator with 5 metre cable and alligator clips as well as Anderson plugs to connect direct to your battery. The solar charge regulator is required to reduce the voltage from the solar panels to around 14 volts which is acceptable for charging your battery.
The solar panels are easy to store in a camper trailer, caravan or motorhome due to their compact size. The obvious benefit of a folding solar panel is to be able to chase the sun and reposition the solar array towards the sun thus maximising charge to your battery.
If you’d prefer to avoid having to take the portable, mobile solar panel kit frame outside each day and follow the sun, perhaps a fixed, permanent solar panel/s on your caravan or motorhome roof might suit you better. We have a range of caravan and camping roof solar panels to suit your free space and particular application. You can mix and match solar panels on your mobile home roof to maximise the available space. What you can’t do though is mix and match your batteries ! We have 10 watt monocrystalline, 20 watt monocrystalline, 35 watt monocrystalline, 80 watt monocrystalline, 120 watt monocrystalline and 160 watt monocrystalline solar panels available. Our current size chart for our Solarking solar panels is listed below (subject to change so please check with us)
Understanding the specifications on each solar panel
Open circuit voltage (VOC) is more important to installers who are connecting 2 or more solar panels in series to produce more voltage. VOC is the open circuit voltage produced by the panel when there is no load on it. You can measure the open voltage by simply connecting your volt meter to the positive and negative wires and taking a reading. It is an important number to know as this is used to calculate the total number of panels that can be connected in series to your inverter or solar charger.
Short Circuit Current (ISC) is the total current produced by the panels when there is no load connected. Switch your volt meter to amp setting and measure the current across the positive and negative wires. So when working out maximum number of panels for your solar charge controller, use this rating not the IMPP rating.
MPP Current (Impp) is the maximum current in amps you’ll expect to see when the panel is at its peak power when connected to your inverter or solar charge regulator.
Mono solar panels have the highest efficiency rate
Monocrystalline modules are space-efficient. Because these modules deliver the highest power output, they require the least amount of space comparing to other solar panels
Mono solar panels have a long lifespan – most manufacturers offer a 25-year warranty on their mono solar panels
They perform better than other types of solar modules in low-light conditions
It is important to keep your panels clean of dirt and debris as this can dramatically affect the power output of your panels so if you do a lot of offroad and dirt travel then be sure to wash them down when you arrive at camp. It’s easy to misdiagnose a faulty regulator or solar charger only to find that a film of red dust on your solar panels is the reason there is no charge to your battery !
Mounting a solar panel on your roof is easy. Simply purchase aluminium angle from your local supplier and pop rivet the angle to the long side of the solar panel allowing for a 1 inch gap between the panel and the caravan or motorhome roof. This will ensure good ventilation and avoid excessive heat build up which can affect the efficiency output of the solar cells. Then, using an adhesive (we recommend bonding your solar panel using Sikaflex Marine) , apply to the underside of the angle and to the contact area of your roof being sure to clean and rough up the surface areas of contact first. Then route the solar wiring in through the van roof and connect inside to your solar charger or regulator then to your battery. If you’re installing multiple roof mounted solar panels on your caravan, 4WD or motorhome roof, connect them in parallel. That is, positive to positive, negative to negative, this way you’ll maintain the voltage of the panel through to the solar reg.
Types of solar regulators (solar chargers)
Maximum power point tracking regulators (MPPT charge controllers) generally offer more features via digital display but most importantly are much more efficient than standard PWM charge controllers – up to 30% more efficient in fact. The MPPT solar charge controller effectively utilises the maximum power output of the panel (as in highest voltage output) to produce the maximum current unlike a standard regulator like a PWM reg. ALWAYS install an MPPT regulator as opposed to a standard regulator. SatPlus stock a good range of EP Solar regulators in 10A, 20A, 30A and a huge 60A version. EP Solar are well respected in the solar industry and are leading edge in design circuitry and innovation.
AGM versus Lithium batteries
An interesting article - https://www.victronenergy.com/blog/2015/03/30/batteries-lithium-ion-vs-agm/