in this video I will walk you through a 5 KW offgrid solar system covering everything from choosing the right components to understanding the costs we will calculate everything in these three simple steps then I will give you some more information about the system itself I'm Nick author of offgrade solar power simplified with over 2,000 reviews I help people create their own upgrade solar systems ready let's get started
Understanding Your 5 KW Off-Grid Solar System Design
Solar Panel Selection
let's start by selecting solar panels for this example I will use Canadian Solar 400 W solar panels to determine how many panels we need divide the total desired solar power which is 5,000 W by the power of each panel which is 400 WS you will need 12 solar panels and we have a total of 4800 Watts
Charge Controller Sizing
next we must calculate the charging current to choose the right charge controller to find the charging current divide the total Soro power which is 4800 W by the charging voltage of 57.6 volts this gives us 83 amps we will use a charge controller rated for 100 amps a good choice is the victron 450 volts 100 amp charge controller
Panel Wiring and Maximum Input Voltage
almost done the next step involves calculating the maximum input voltage when looking at a sor panel specifications note the open circuit voltage or vocc which is 36.8 volts we cannot wire all 12 panels in series because the voltage would exceed the charge controllers 450 volt input limits instead split them into two groups of six panels each connecting them to the charge controllers to mppt inputs let's check the maximum input voltage six panels * 36.8 vocc * 1.25 which is a safety Factor equals 276 volts this is within the upper limit of 450 volts the startup voltage is 120 volts we add two DC Breakers of 20 amps each before the charge controller's input to isolate the panels when needed after the next step we are going to size an inverter and gener erator
Battery Sizing, Inverter, and Backup Generator
Battery Bank Sizing
step two is sizing the battery for our 5 KW offgrid solar system normally you would start with the load analysis then size the battery on the amount of solar this time we know the amount of solar from the start so we have to work backwards when we look at the sun hours for Vancouver we can see that we have several months over three Sun hours for the months without three Sun hours we will use use a generator to recharge the battery using a generator will be cheaper than design the system for a minimum of one Sun hour in December so you will work with three Sun hours 5 KW of solar panels will generate about 15 KW hours of energy per day to store this energy you would need a battery with a capacity of at least 15 Kow hours for a 48v system this can be achieved with three 48 volt 100 amp hour Ser batteries in parallel each storing 5 KW hours this battery capacity ensures you can store all the energy generated during the day to use when the sun isn't shining keep watching to figure out how much power we can use daily in step three we will choose an inverter and a backup generator
Inverter Selection and Features
the inverter will convert the DC electricity stored in your batteries into AC electricity that that your household appliances can use I recommend the victron multiplus 48 volt 5,000 VA low frequency inverter here's why low frequency inverters tend to last longer it can handle surge loads better which is useful when starting appliances like refrigerators pumps or table saws it has a low idle power consumption of only 15 watts it can work with a generator to recharge the batteries when solar power isn't enough
Backup Generator Sizing and Operation
let's size the backup generator a generator can help recharge your batteries during cloudy days or long periods without enough sunlight the victon multiplus inverter has a 70 amp charging limit I recommend the Honda 3000 W inverter generator using 70% of the inverter's power output is recommended to increase fuel efficiency and reduce noise multiplying the generator output with 70% we get 2100 watts to figure out the maximum charging current we divide the charging Power by the charging voltage and we become 36 amps we can adjust the charging current from 70 amps to 36 amps in the multiplus software using an MK3 USB dongle it will take 7 hours to fully recharge a 15 Kow battery with the generator stay tuned to find out what the system can run now
System Wiring, Daily Consumption, and Cost Breakdown
Wiring and Fuse Specifications
now let's talk about the wiring and fuses for our 5 KW upgrade solar system if your panels are 50 ft or 15 M from the charge controller you would need a 14 gauge solar cable as seen in this voltage drop calculation since there is no 14 gauge PV cable we will use 12 gauge the charge controller outputs 100 amps applying a 1.25 safety Factor you would need a cable that can handle 125 amps use 4 gauge welding cable which can carry up to 150 amps install a 125 amp clost defuse to protect the cable the inverter will draw a maximum of 104 amps applying the 1.25 safety Factor the maximum current is 30 amps again use a 4 gauge welding cable and a 125 amp fuse while the calculated current is slightly above 125 amps the fuse will not blow at 130 amps as we can see in this curve of the 120 amp fuse
Daily Energy Consumption Analysis
now many of you might ask what the system can run first we must figure out how much power we can consume daily upgrade solar design States you need 3 days of autonomy if we divide the battery total power of 15 KW hours by 3 days we have 5 KW hours of energy consumption per day in this load analysis we can use a fridge a TV several lights a microwave a freezer and a computer lastly we have to factor in the inverter idle power consumption we become a daily energy usage of 4600 W hour as you can see it's not much for 5 KW of solar many people who order my solar review service have asked me to create a system like this for tiny houses or cabins
Cost Breakdown of the 5 KW Off-Grid System
let's break down the cost of this 5 kwatt offgrid solar system solar panels $2,000 battery $4,500 charge controller $11,200 inverter charger $1,000 $700 generator $2,000 wiring $400 fuses and Breakers $100 the total cost of the system is approximately $112,000 I have linked all the components in description from my recommended stores using these links helps me buy more solar equipment to test on the channel at no extra cost to you if you want more upgrade solar diagrams like this one check the first link in description or pin comments to get them for free with explanations about their sizing including wires and fuses just like this video do you have questions about the system let me know in the comments thanks for tuning in and I will see you in the next one
5 KW Off-Grid Solar System Technical Specifications
| Feature | Detail |
|---|---|
| System Type | 5 KW Off-Grid Solar System |
| Solar Panels | 12 x Canadian Solar 400 W (Total 4800 W) |
| Charge Controller | Victron 450V | 100A |
| Battery Capacity | 15 kWh (three 48V 100Ah batteries in parallel) |
| Inverter Charger | Victron Multiplus 48V 5000VA (Low Frequency) |
| Backup Generator | Honda 3000W Inverter Generator |
| Panel Cable Gauge | 12 gauge PV cable (for 50 ft / 15 M distance) |
| Charge Controller Output Cable | 4 gauge welding cable (150A capacity) |
| Inverter Cable | 4 gauge welding cable |
| DC Breakers | 2 x 20 amps (before charge controller input) |
| Fuses | 125 amp Class T fuse (charge controller output and inverter) |
| Daily Energy Generation (3 Sun Hours) | 15 kWh |
| Daily Energy Consumption (3 Days Autonomy) | 5 kWh (actual usage after idle power: 4600 Wh) |
| Estimated Total System Cost | ~$12,000 |
Frequently Asked Questions
Q: What type and how many solar panels are recommended for this 5 KW off-grid system?
A: This system recommends 12 Canadian Solar 400 W solar panels, totaling 4800 Watts.
Q: What battery capacity is required to store the daily energy generated, and how is it achieved?
A: A battery with a capacity of at least 15 kWh is needed. This is achieved with three 48 volt 100 amp hour batteries wired in parallel.
Q: What is the estimated total cost for this 5 KW off-grid solar system?
A: The total estimated cost for all components in this system is approximately $12,000.