A typical home uses 20kWh of energy a day. A 5kW solar system would meet most of the daytime power needs of such a home (Based on 4 hours sunshine per day.
You need at least 10 degrees tilt for rain to reliably run off the panels and clean them.
In NZ – 45 degrees facing North
- Solar PV (Photovoltaic) – Makes power
- Solar Thermal – Makes hot water
- Solar PVT – Hybrid of both
When solar panels are wired in series, the voltage of the panels adds together, but the amperage remains the same.
Wiring solar panels in parallel causes the amperage to increase, but the voltage remains the same.
A charge controller is a determining factor when it comes to solar panel wiring. Maximum Power Point Tracking (MPPT) charge controllers are for wiring solar panels in a series, where Pulse Width Modulation (PWM) charge controllers are used to wire solar panels in parallel. String inverters have maximum power point trackers (MMPT) in them that can vary the current and voltage to produce the maximum amount of power possible.
Solar PV
Recommended panel brands:
Q-Cells | Risen | Trina | Jinko | Phono | Sunpower (Maxeon) | Seraphim | Canadian Solar | Suntech | REC | JA Solar | Tindo | Longi (Longi Leeri) | Winaico | SolarWatt.
Here are more top suppliers (2018)
- Hanwha Q Cells – South Korea
- First Solar – U.S.A.
- Motech Solar – Taiwan
- Yingli Solar – China
Install up to 33% more panels than the inverter is rated at
Approx 25Kg per panel, 1.2m x 2m footprint – 12-32 panels. Current plan has 50sqm roof available (20 panels max)
Panels should be installed in a way that allows air to circulate underneath to help keep them cooler.
The NIWA calculator estimates the solar energy that can be collected by a solar capture device (solar panel) at a given address, panel direction and roof slope.
niwa.co.nz/our-services/online-services/solarview
Recommended inverter brands:
Longi (#1 in the world) | ABB | SMA | Fronius | Goodwe | SolarEdge | Delta |Huawei | Sungrow | Enphase | Soltaro (was Solis).
Solar Charge Controllers
- Key features that you need to look out for:
- It is a true MPPT Controller which will deliver 99% efficiency
- Can be used for over-paneling (which means you can add more panels than what it is rated for). This feature is very hard to find, but present in all of the controllers that I recommend
- Temperature Compensation- This increases the life of your batteries
- Manual charge profiles (charge any type of battery): Only for advanced users. This will allow you to fine tune your charge profile to a specific battery
- Large and strong input terminal that can accommodate large wire gauges (very hard to find)
Inverters
selectsolar.co.uk/prod/1602/solis-40kw-5g-3-phase-quad-mppt-dc#overview $6000 inc. Freight. (Good brand)
£2679 for 40kW
£2060 for 20kW
Rating: 40,000W / 20,000kW
Phases: 3
The Solis Quad MPPT 3 Phase Inverter range is designed specifically to meet the requirements of a simple, low cost installation where a quad MPPT inverter is required.
THIS INVERTER COMES WITH A 5YR STANDARD WARRANTY
Other attributes include:
- Over 99% Max. efficiency
- 200V-1000V input voltage range
- 7.0″LCD color screen display (optional)
- Three MPPT design with precise MPPT algorithm
- Up to 30% DC input oversize, 12.5A input for each PV string
- Compact and light design, easy installation
- IP65, visually pleasing for domestic environment
- RS 485, WiFi/GPRS (optional) interface
- 4 strings
- Numerous protection functions
- WiFi and monitoring app available
String Inverters vs. Microinverters:
- String Inverters are far cheaper than microinverters because it connects all the solar panels through one simple connection or series. The problem with this is if one solar panel breaks or drops in efficiency, the other panels down that series will also be affected. (String-Inverters are even said to increase the chances of fire hazards and the drop in efficiency much faster!!)
- Micro-inverters however allow each solar panel to act independent of one another. So, if one breaks, it won’t impact the others. This reduces the chances of fire hazards and will allow the solar panels to last much longer.
- The key to receiving maximum production from your panels relies more on the managing of it rather than the production.
- Include a live monitoring system for the solar panels. This way you can detect if your panels are producing the energy you need.
Microinverters
600 watt Duo Micro-Inverter APSystems, YC600-240V $245 each (16k USD for 60)
A single-phase, smart grid-compliant microinverter, the YC600 serves two modules with dual, independent MPPT. Zigbee wireless communication over a mesh network offers faster data speeds than PLC and a wider MPPT voltage range results in a greater energy harvest for homeowners. 10 years standard warranty, optional extended 25-year warranty available.
| MODULE COMPATIBILITY: | 60 and 72 cell PV Models”; Recommended PV Module Input Power=410W+” |
| MPPT VOLTAGE RANGE: | 22v-48v |
| OPERATION VOLTAGE RANGE: | 16v-55v |
| MAXIMUM INPUT VOLTAGE: | 55v |
| MAXIMUM INPUT CURRENT: | 12A x 2 |
| MAXIMUM TOTAL PV ARRAY SHORT CIRCUIT CURRENT: | 15A |
| OUTPUT DATA (AC): | 240v |
| MAXIMUM CONTINUOUS OUTPUT POWER: | 548VA |
| PEAK OUTPUT POWER: | 600VA |
| NOMINAL OUTPUT VOLTAGE: | 240v |
| NOMINAL OUTPUT CURRENT: | 2.28A |
| NOMINAL OUTPUT FREQUENCY: | 60Hz |
| ADJUSTABLE OUTPUT VOLTAGE RANGE: | 211-264V |
| ADJUSTABLE OUTPUT FREQUENCY RANGE: | 59.3 – 60.5Hz |
| POWER FACTOR (ADJUSTABLE): | 0.8 leading, 0.8 lagging |
| TOTAL HARMONIC DISTORTION: | <3% |
| MAXIMUM UNITS PER BRANCH: | 7 (14 PV modules) |
| PEAK EFFICIENCY: | 96.7% |
| CEC WEIGHTED EFFICIENCY: | 96.5% |
| NOMINAL MPPT EFFICIENCY: | 99.5% |
| NIGHT POWER CONSUMPTION: | 60mW |
| OPERATING AMBIENT TEMPERATURE RANGE: | -40°C to +65°C |
| STORAGE TEMPERATURE RANGE: | -40°C to +85°C |
| DIMENSIONS (WXHXD) INCHES (MM): | 260mm x 188mm x 31.5mm |
| WEIGHT: | 2.6kg |
| AC BUS MAXIMUM CURRENT: | 20A |
| CONNECTOR TYPE: | MC4 Type |
| ENCLOSURE RATING: | NEMA 6 (IP67) |
| COOLING: | Natural Convection – No Fans |
| COMMUNICATION: | Wireless Zigbee |
| TRANSFORMER DESIGN: | High Frequency Transformers, Galvanic Isolation |
SG600 Inverter $72NZD (5k NZD for 60)
| Model | SG600MD (Regular) | SG600HD (Custom-made) | SG600TD (Custom-made) |
| Input Data (DC, PV) | |||
| Number of Input MC4 Connector | 2 set | 2 set | 2 set |
| MPPT Voltage Range | 24V-40V | 36V-60V | 80V-115V |
| Operation Voltage Range | 18V-50V | 30V-70V | 70V-120V |
| Maximum Input Voltage | 50V | 70V | 120V |
| Startup Voltage | 18V | 30V | 70V |
| Maximum Input Power | 2*300W | 2*300W | 2*300W |
| Maximum Input Current | 2*12A | 2*8.3A | 2*3.7A |
| Output Data (AC) | |||
| Single-Phase Grid Type | 120V & 230V | ||
| Rated Output Power | 590W | ||
| Maximum Output Power | 600W | ||
| Nominal Output Current | @120VAC : 5A / @230VAC : 2.6A | ||
| Nominal Output Voltage | 120VAC / 230VAC | ||
| Default Output Voltage Range | @120VAC : 80V-160V / @230VAC : 180V-280V | ||
| Nominal Output Frequency | 50Hz / 60Hz | ||
| Default Output Frequency Range | @50Hz : 47.5Hz-52.5Hz / @60Hz : 57.5Hz-62.5Hz | ||
| Power Factor | >0.99 | ||
| Total Harmonic Distortion | THD <5% | ||
| Maximum Units per Branch | @120VAC: 4 units / @230VAC : 8 units | ||
| Peak Efficiency | 95% | ||
| CEC Weighted Efficiency | @120VAC: 92.5% / @230VAC : 93.5% | ||
| Nominal MPPT Efficiency | 99.9% | ||
| Night Power Consumption | <700mW | ||
| Mechanical Data | |||
| Operating Ambient Temperature Range | -40°C to +65°C | ||
| Storage Temperature Range | -40°C to +85°C | ||
| Dimensions (W x H x D) | 185mm x 180mm x 38.5mm (not include connectors and cable) | ||
| Weight | 1.5kg | ||
| Max Current of AC Bus Cable | 20A | ||
| Waterproof Grade | IP65 | ||
| Cooling Mode | Natural Convection – No Fans | ||
| Communication (Inverter to DataBox) | 2.4G Wireless | ||
| Transformer Design | High Frequency Transformers, Galvanically Isolated | ||
| Integrated Ground | Equipment ground is provided by the PE in the AC cable. No additional ground is required. | ||
| Protection Functions | Isolated Island Protection, Voltage Protection, Frequency Protection, Temperature Protection, Current Protection, etc. | ||
| Design Compliance | NB/T32004:2013, NB/T32004:2013, EN61000-3-2, EN62109, VDE0126, UL1741 etc. | ||
Micro Inverter Monitoring
NETMS PV Smart Monitoring System
- Maximum up to 999 units Mircoinverters per DataBox / DataPlus
- USB interface to PC
- 2.4G wireless communication and monitoring
- Power by USB without external power supply
- Communication Distance:50 meters (Visual Distance)
- Communication Protocol:NETSGP1.2
NETMS – Monitoring Software
- OS: Windows OS
- Minimum RAM Requirements: 1GB
- Min. Disk Available Space: 1GB
- Data Storage Location: Local hard disk
Batteries
C10 is fast discharge, C20 is medium discharge
Lithium Ion Phosphate batteries. Longer lasting, cheaper.
powertech.co.nz/products/48-volt-500-ah-battery-kit-narada-rexc-deep-cycle-lead-carbon
24 X 2 Volt Block, 500Ah C10, Battery Racking, Interconnecting Cables & Covers
Perfect for all 48 Volt DC Off-Grid and Grid Connected Hybrid Solar Systems
The REXC series is a high performance, high cycle life lead carbon battery. Combining advanced lead carbon technology & REX VRLA technology, the REXC lead carbon battery offers extra-long cycle life, excellent partial state of charge cycle performance (PSoC), significantly faster recharge rates and large current discharge performance.
The REXC Series is specifically designed for cycling energy storage systems, including Off-Grid Solar, Grid Connected Solar Hybrid systems & Diesel Battery Solutions.
Specific Racking solutions are available in standard configurations in 24, 48 & 120 Volt DC, Vertical or Horizontal Mount.
Technical Features:
(Typical values @+25 ºC for batteries stored for one year or less)
- Advanced Lead Carbon Battery
- Combines advantages of lead acid battery & super capacitors
- Excellent recharge acceptance & super fast charge/large discharge performance
- Outstanding PSOC cycle performance
- Innovative robust design inside ensures superb safety and reliability
- Horizontal installation position for less space, easy installation & maintenance
- Self-regulating pressure relief valve with flame arrester
- Flame retardant ABS case (UL94 V-0, optional)
- Low self-discharge rate
- High gas recombination efficiency (>99%)
- Complies with IEC, IEEE, UL, EN, CE standards, etc.
- Design life at 25°C (77°F): 20+ years (2V), 20+ years (12V)
Application Examples:
- Energy storage systems
- Hybrid energy systems – solar, wind & Hydro energy
- Generator & battery hybrid energy systems
- Emergency lighting systems
- Demanding standby, cyclic systems
REXC 2 Volt Series General Specifications:
| Type | Rated Capacity (Ah) | |
| Capacity @ C10 1.80 Vpc @ 25℃ | Capacity @ C120 1.85 Vpc @ 25℃ | |
| REXC-200 | 200 | 240 |
| REXC-300 | 300 | 360 |
| REXC-400 | 400 | 480 |
| REXC-500 | 500 | 600 |
| REXC-600 | 600 | 720 |
| REXC-1000 | 1000 | 1200 |
Narada wholesale/retail supplier since 2007 coromandel.com
The 48V battery banks can be either 4 layers or 6 layers high.
There is a New Zealand and Australian standard (AS/NZS 4509.2 “Stand-alone power systems – System design”) that gives detailed information on designing an off-grid solar system. This is so comprehensive that it has been used by other countries and many companies for the basis of their own design software. Unfortunately, it is not sponsored by MBIE as a free download and users must pay $198 + GST to get a copy.
However this document is quite light on battery sizing information and does not fully take account of different battery technologies and performances and changes over the last 10 years. It dated 2010 and although “reaffirmed” in 2016 is now somewhat out of date.
When considering the size of your battery bank there are a number of key considerations:
- are you going to use a generator to handle larger appliances and/or to provide power after extended periods of cloudy weather or in winter?
- is your solar array capable of charging the battery bank at the recommended charge current rates?
- if you are not using a generator, how many days of bad weather will the system handle before you run out of power?
- the manufacturers recommended depth of discharge (DoD) for each battery type or model you are considering?
Here are some examples of system sizing using lead-carbon batteries (note that none of these include a generator as it is generally more economic to have more solar panels and slightly bigger battery bank than have a generator to deal with cloudy days):
Remote hut or workshop/shed with intermittent but occasionally heavy use:
600 watts solar panels (2 x 300W)
2 x 6V 6REXC-300 batteries (12V, 3.6kWh capacity)
40 amp MPPT controller
1000 watt inverter
Tiny house with basic appliances, gas cooking and HW, full time occupation by 2 people:
- 5000 watts solar panels
- 24 x 2V REXC-600 (48V 28.8kWh capacity)
- 2 x 50 amp MPPT controller (2 sprigs of panels)
- 5000 watt inverter
Switch your power to Trustpower on a 24-month term, Trustpower will buy back your extra solar generation at 16c per unit (excluding gst). Maximum of 500 units per month and is guaranteed for the life of the 24-month contract.
DIY Solar Power with Will Prowse
- Do not turn the battery “on” until everything is connected! After the battery is turned on, you can safely turn on the inverter.
- Connect the solar panel wires at night. This will ensure that you are never handling high voltage.
- The 24V battery can only output 2400W! And the 48V battery can output 4800W. If you need more output capacity, you need to add more batteries in parallel.
- If you wish to add another battery, connect it in parallel with a second set of battery cables (Google search “parallel battery connection”). You simply connect the positive of one battery to the positive of the other. And negative to negative.
- If you have more than 3 batteries, you should add a T-Class Fuse. This is a special type of fuse that will disconnect power regardless of how many batteries you have connected. Connect all of your batteries in parallel, then connect the positive wire to a T class fuse. Then connect the other end of the T class fuse to the all-in-one system.
- If you have to put your solar panels in parallel groups (to keep the voltage down), you can avoid the use of a combiner box by using inline MC4 fuses. They take seconds to install and will protect your array from problems. Furthermore, use a MC4 branch adapter (any will do) to connect the parallel strings together.
- Be sure to use the solar panel calculator (listed in video description as well) to calculate what voltage your solar panels will produce. This is the only difficult part of this system. Every solar panel has a different voltage, and how you wire them up will change their voltage. Check out the easy to use calculator here: solarchargecontrollercalculator.com
How to design a solar array wiring configuration:
Consumption monitors are small devices that sit in your switchboard. They cost around $500, and measure how much electricity is coming from or going to the grid.
First – the absolute basics. The sun rises in the east, and sets in the west.
This means:
- East-facing panels will generate more power in the morning.
- West-facing panels will generate more in the late afternoon.
- North-facing solar panels will generate the most energy overall, but less in the morning and late afternoon compared to east and west-facing panels respectively.
- East and west-facing panels will produce about 15% less energy per year compared to north facing.
But – a working household can consume more solar energy with east and west-facing panels, because they produce more energy before and after school/work, accelerating their system’s payback compared to a north-facing one.
BMS – Battery Monitoring System – 100Ah @48v = 4800Wh = 20A @230v Run 48v to save wiring cost, inverter cost etc. To extend battery life – Set absorption: 58V overkillsolar.com/product/bms-100a-16s-lifepo4-12/ $170USD
Auto sun Tracking for Solar Panels. Adds 20-35% more power:
classic-edu.com/en/solar/st.html
Simple autonomous solar tracking system: youtu.be/wL9PcGu_xrA
Heat exchangers – Counterflow is 20% better than cross flow
Cable
Cable sizing calculator
wecobatteries.com/cable-sizing
Design Software
https://www.solaredge.com/StorEdge-solutions
Monitoring
Cloud Connect Advance Tigo CCA + TAP
This kit is comprised of the Tigo TAP access point and Tigo’s Cloud Connect Advanced (CCA), one of the smallest solar data loggers on the planet, providing valuable insight into module-level performance data. It enhances the monitoring and security capabilities of Tigo smart modules. €270.50
