Your cart is currently empty!
Category: Tech Tips
Parallel VS Series: the solar panel edition
When panels are in series the voltage adds up and the current remains the same, whilst in parallel the voltage remains the same and the current adds up, the wattage will always increase in both configurations.
For example:
Four 250W panels with the specifications of 45Voc and 5A (Isc) in series will total to 1000W, 180Voc and 5A (Isc).
Four 250W panels with the specifications of 45Voc and 5A (Isc) in parallel will result in 1000W, 40Voc and 20A (Isc).
A couple of useful bonus tips:
- Panels should always be matched, e.g. the same Voc, Isc and wattage.
- Check the specs of your solar controller and be careful not to exceed the max Voc, Isc and wattage.
Parallel VS Series: the battery edition
When configuring a smart shunt or battery monitor, a common mistake we see is people adding up both the amp-hours and the voltage of their battery bank, ending up with a much higher figure for amp-hours than they really have.
Remember:
When batteries are in series, voltage increases whilst amp-hours remains the same.
For example:Four 12v 100Ah batteries in series will result in 48v, 100Ah with 4800wh capacity. When batteries are in parallel amp-hours increase but not voltage.For example: Four 12v 100Ah batteries in parallel will result in 12v, 400Ah giving 4800wh capacity.These battery wiring diagrams help illustrate the difference in parallel and series configurations.
Please be aware: parallel banks require fusing when combining with a distribution system as illustrated in the 24V & 48V diagram.
Heat & Solar Panel Performance
It’s the middle of summer. It’s hot. Solar radiation is at it’s peak, but your solar panels are not quite performing at their peak. If you’re wondering what could be going on, our tech team are here to explain.
PV cells work mostly on the visible spectrum, the irradiance is what is important and the heat works against us reducing efficiency.
Panels are tested at 1000 W/m2 at 25ºC to determine peak power rating. Each degree above this rating affects the panel output performance by 0.38% on average (check your panel spec sheet for the exact figure for your panel). Monthly average temperature variations can result in fluctuations in panel performance.
If you want to know how much of a fluctuation is possible check out image 2. You can see that the percentage loss due to summer temperatures is way higher than winter.
Even though the power yield is higher in summer, this is also true for inefficiencies.
Heat & Electrical Device Performance
Temperature affects electronics and electrical devices in all sorts of ways.
The internal resistance of every part or elements goes up, creating greater heat dissipation and as a result, the efficiency and performance of the system spirals down. It also wears down the lifespan of your electronics.
Remember:
Check the datasheet of your product, ie, Victron Inverter/Chargers which provide the temperature performance values.Hot tip: A temperature controlled room will make sure your system performs at its peak.
Check & Tighten your Terminals
As the weather heats up, loose connections can become an issue.
As your copper cabling expands and contracts, once secure terminals can work loose. Even if you’ve done the best job possible during your build, time and temperature fluctuations can wreak havoc.
Follow our tips for the best chance of preventing loose connections, and always check your terminals as the seasons change.
Tips to prevent loose connections:
- Proper placement of spring washer
- Use thread locker
- Correct sizing of eyelet
Tilt Angle & Performance
If you want to maximise average performance across the year, you should have your solar panels at a specific tilt angle depending on your location.
- In Perth the best angle is 30º, the same as in Brisbane and Alice Springs.
- Further North in Port Hedland you’re looking at 25º, the same as Townsville.
- Down South in Albany, 35º is ideal, an angle shared by Adelaide, Canberra, Melbourne and Sydney.
- At either end of the tilt angle spectrum in Australia sit Darwin at 20º and Hobart at 40º.
We sell a variety of tilt frame options to help you optimise your panel performance. If you are someone who has more than enough performance in summer but are looking to boost winter performance, you can even add 5 degrees to your tilt.
Why you need a SmartShunt on your lithium battery
A SmartShunt is almost essential on a lithium battery system if you want accurate data on the state of charge of your batteries.
Using voltage as a state of charge indicator as you might on a lead-acid battery does not work on lithium as the voltage barely changes between 10% and 90% depth of discharge.
A SmartShunt delivers data directly to your device using the VictronConnect App providing convenient system clarity in the palm of your hand.Shop SmartShunt’s
Victron SmartShunt 500A/50mV
Original price was: $134.20.$119.00Current price is: $119.00.52 in stock
Fuses: Safeguarding your System Wiring
When calculating the fuse for your system, remember: The fuse’s primary role is to safeguard the wire’s integrity.
They shield against potential fire hazards by breaking the circuit if something goes wrong.
- Ensure your fuse size is above the circuit’s operational current and below the wire’s maximum current rating.
- Prioritize system safety by understanding that a well-sized fuse is your wire’s first line of defense.
The following three steps will help you determine the best type and size of fuse for your system.
- Analyze Current: Determine the maximum operational current of your circuit. Example: 120A
- Select Cable Size: Based on current analysis, choose an appropriately sized cable. Example: 4 AWG.
- Identify Load Type: Assess if your load is mainly resistive (e.g., heaters) or inductive (e.g., motors).
Resistive Load (Fast-Action Fuse):If resistive, opt for a fast-action fuse, ensuring quick response to protect against overcurrent. Example: 150A fast-blow fuse.
Inductive Load (Slow-Action Fuse):For inductive loads, choose a slow-action (time-delay) fuse to accommodate inrush currents. Example: 150A time-delay fuse.
Check Manufacturer Recommendations when possible! If you need more advice our sales team are always happy to help.
Shop Fusing
Fusing
All your off-grid, DC electrical circuit protection needs are covered with ANL fuses, Blade fuses, FH type fuses and Victron megafuses, plus housing and holders.
VSR’s & Smart Alternators
Smart alternators (prevalent in most vehicles made after 2006) provide efficient, variable voltage output, reducing emissions and enhancing battery charging. However, this voltage fluctuation doesn’t work well with traditional charging technology like VSR’s (Voltage Sensitive Relay’s).
The VSR’s depend on a constant voltage higher than 13.3V in most cases to be able to charge the auxiliary battery setup. A smart alternator in junction with the ECU of the car will decide when the starter battery is fully charged after cranking and dial the working voltage down after that, causing the VSR flick open and stoping the charging.If you have a smart alternator a DC-DC charger is essential.
These chargers efficiently convert and regulate their working voltage, ensuring your leisure battery receives the right charge, maintaining power on the road.
Shop DC-DC’s
DC to DC
Charge and maintain your batteries with DC to DC charging, our range includes convertors and isolated and non-isolated options from brands such as Victron and Enerdrive suitable for 12v, 24v or 48v.
What’s the difference between solar panel types?
With a wide variety of solar panels available, understanding their differences and benefits will help you find the most suitable panel to meet your needs. The following four panel types are the most common varieties we stock at Alt-Tech.
Shingled Cell Solar Panels:
A Strip-over-strip design boosts power per SQ meter, no busbars and increased sunlight exposure. Reduced potential of micro-cracks.Use Case:
Limited space applications where generating the most power possible is imperative.Monocrystalline Silicon Panels:
A popular choice for decades, pure crystal cell formation results in slightly greater efficiency. Dark black appearance.Use Case:
Residential and commercial applications.Polycrystalline Solar Panels:A cost-effective choice due to quicker production. Good for mobile applications as they are generally corrugation resistant.
Use Case: Common in residential installations.
Thin Film Solar Panels:Less efficient per SQ metre but excellent performance in low-light conditions. Thin film’s are less affected with temperature and shading.
Use Case: Low light sites with good amount of space to mount them.
Second-life panels are our preferred choice and we always have a range of thin film, poly and mono panels in stock. Only new shingled cell panels are available at present, due to being newer technology.
Our knowledgeable sales team are always ready to offer further advise on the best panels for your system.
Shop Solar Panels
Solar Panels
We stock a massive range of new and second life panels, assessed and covered by five year warranty, offering affordable, reliable options for your off-grid solar project.
Over 80% of the solar panels we retail are second-life or warehouse seconds. This means that availability of specific panels is unpredictable. Stock levels listed reflect real-time availability and if levels are lower than your requirements, your best option is to choose a different panel. It could be six months, a year, or we may never receive more of a particular panel.
For more information on second-life and warehouse second panels, please check our FAQ.
