4000 watt, 24v Off-grid solar power system

Recommended Components (scroll to bottom of page to see what products I recommend):
  • 400-4000 watts of solar panels
  • ​2x 40 amp MPPT charge controller with over-current protection 
  • 4x+ 12v,100 ah LiFePO4 Batteries (wire these 4x batteries in series/parallel to create a large 24v battery bank)
  • 3000 watt, 24 volt inverter
  • 40amp DC-DC Converter for 12v appliances. 24v goes in, 12v goes out
  • Battery Protect by victron energy, 2200 amp
  • 2 gauge copper wire and lugs/heatshrink
  • 50 amp circuit breaker for the MPPT's​, 25 amp fuse for the converter
  • Wooden board to mount the components
This system is a beast! It can handle any solar panel array up to 4000 watts, can handle a large battery bank of 24/12/6 batteries wired to 24 volts, and can power a large 24 volt inverter (inverter size will be limited to battery size in this situation)

Can this system charge my tesla car or other electric vehicle?

Technically it is capable of level 1 charging a tesla car, but ​I must stress that this is only possible while sunny, but the moment the sun goes below 45 degrees of horizon, it will switch to battery/grid. So it is good to supplement your charging system and reduce your overall bill, but that's about it. If you have full solar power coming in, it will take 96 hours! and each day only has 5-6 hours of full sunshine available. So this system should be seen as a backup. To build a solar array capable of charging at 240 volts, you would need to spend 50k or more. Not really worth it. 

This system is a great idea for people with electric motorcycles! You can charge it no problem with this system.


If you are not familiar with 24 volt systems, check out my video: Click Here to watch my 12v vs. 24v Video
Pros of a 24 volt System:
  • Lower Financial Cost Compared to 12v System. Save a lot of $$$
  • Higher Efficiency of Components and Wires
  • Higher Power Output from Smaller Components
  • 24 volts is considered a very "safe" voltage to work with
    ​
Cons of a 24 volt System:
  • You need a higher voltage solar panel array. Not really a con because you should be series connecting your panels anyways. Open circuit voltage of solar panel array must be at least 40+ volts if you plan to charge a 24 volt battery with it. This means that if you are using 12 volt panels (open circuit of 17-20 volts), you will need to series connect your panels to create a larger voltage.
  • Difficult to source 24 volt solar system components locally. 12v is easy to find at stores, 24v components require ordering online.
  • Difficult to charge with a vehicle alternator. I do not suggest anyone charging a deep cycle battery with an alternator regardless, but some people still insist upon it. If you have a 24 volt system, you will need some special circuits that are extremely expensive to get it to work. Or buy and install a 24 volt alternator.
  • If you have 12 volt appliances, you will need to run them with a 24v to 12v converter. Very easy to do!

​In my opinion, the pros dramatically exceed the cons. If you are trying to convert your system to 24 volt, it may not be worth it. But if you are building it from the ground up, a 24 volt system is a great way to go!
Step 1: Mount components to a wooden board like this:
This picture should give you a rough idea of how to mount and connect your components. Each system is different though, so be sure to use my book to calculate the fuse and wire gauge size for your components. This picture does not cover other remote wires/shunts/temperature compensation wires etc, so please be sure to use my book to understand how this all works!
Step 2: Connect to 24v Battery Bank
If everything is installed correctly, the solar charge controller should now turn on, and you should be able to run the inverter. You may see a small spark when you connect the inverter to a battery, and this is completely normal.

Step 3: Mount Solar Panels to the roof and Connect them to Solar Charge Controller

If you follow the previous steps correctly, the solar charge controller should now be charging your battery! (if there is sunshine present)
​For more information on how to do this, please check out my book :)

Components I recommend for this system:

Buy 400-4000 watts of Either Glass or Flexible solar panels

Glass Solar Panels
​(recommended)

Pros:
  • Cheap (usually)
  • Extremely durable (can handle snow, rain, heat for years!)
  • Easy to mount on a vehicle's roof. Click Here to learn how
  • Last 25+ years, no problem

Cons: 
  • Heavy. Typically around 16 pounds for a 100 watt solar panel
  • Can cause a huge amount of aerodynamic drag to your vehicle
  • Mounting glass panels to the roof of a moving vehicle is typically a bad idea. If one of these falls off your roof, someone can die. Make sure you mount all panels properly.
  • Requires air flow under the panel. Just an inch or so, not much, but it is necessary. 

400 watts of Glass Solar Panels
Click here

Flexible Solar Panels

​Pros:
  • Lightweight
  • Easy to mount
  • Aerodynamic efficiency (they are designed to be flush mounted on your roof, which means better gas mileage for your vehicle.
Cons:
  • Longevity issues. Typical life is 5-10 years. (Glass panels can last 25 years+)
  • Expensive
  • Cheap materials (and connectors)
  • They can bend.. but not too much. Anything more than a 30 degree radius will cause damage of the solar cells ( you will hear a distinct crunch, and you may see cracks in the cells)
  • They like to over heat. If you are in arizona, they will die in less than a year. If you use them in a cool environment, 5-10 years is average.
100 watt Flexible Solar Panels
Click here

Buy X2 40 amp mppt solar charge controller:

Max. Solar Input Power:
You can hook up a maximum of 2080 watts of solar power to this charge controller (only when the controller is used with a 24v battery). The max charge rate is limited to 40 amps at 24v. ​

​The benefit of having 2000 watts attached to this 40 amp controller is that there is more power production during sunrise and sunset times. If you wish to harness the entire 2000 watts of solar power, use a 60 or 80 amp charge controller: (Click here to see other charge controllers)
​
Be sure to read the instruction manual. Lots of really fun features in this controller!

​40 Amp MPPT Charge Controller kit: Click Here for a cheap price

Choose a battery:

12 volt Sealed Lead Acid
Buy 8-16 of these:
155 amp hour AGM Sealed Lead Acid Battery
​Click Here for a cheap price
  • Weight: 190 pounds total
  • ​Charge Cycle Life: 500-1,000 cycles
  • Depth of Discharge(how much of the batteries capacity you can actually use): 50%
  • (Cheaper initially, but expensive in the long run)
or
12 volt Lithium Iron Phosphate 
​(recommended)
​Buy 4 - 12 of these (whatever you can afford):
A 100 amp hour Lithium Battery
Click Here to buy it on Amazon.com
Click Here to buy it directly from Battle Born
​
  • Weight: 60 pounds total
  • ​Charge Cycle Life: 3,000-5,000+ cycles
  • Depth of Discharge(how much of the batteries capacity you can actually use): 100%
  • (This battery is expensive initially, but much cheaper in the long run)
This battery can safely be series connected to create 24 volts. Not all lithium batteries can do this! Stick to battle born if you are building a 24 volt system.
Click here to learn more about this battery

24v, 3000 watt inverter:

Wire and Adapters:

High-Quality Copper Wire for DC appliance hookup
(most wire on amazon is "copper clad aluminum", which is cheaper but lower in quality):

50 feet 10 gauge Blue/Black
Click Here
​Solar Panel Array to Solar Charge Controller Cable (this cable goes through your roof):
​ 
Click Here
​Battery to Battery Cables

Any size battery (be sure to select the right size for your battery bank) Click Here
​Pre-fabricated Battery to
​Inverter Cables
​(if your inverter does not come with them)
make sure that the holes on the connector will work with your battery/inverter

12 volt 500-1100 watt inverter
​0r 24 volt 1000-2200 watt inverter  
Click Here

12 volt 1000-2000 watt inverter
or 24 volt 2000-4000 watt inverter 
Click Here

12 volt 2000-4000 watt inverter
​or 24 volt 4000-8000 watt inverter
​Click Here
Main Component Hook-up wire/connectors/heatshrink
Requires a Hammer-type Crimper and Assembly. Great for custom built systems where length of each wire matters. If you are a beginner, stick to pre-fabricated cables.

Click on a link below and choose your length
​(default length is 10 feet of red, 10 feet of black): 
Solar Panel Cable Entry Gland

When your solar panel array wires enter your vehicle, you will need to drill two holes. Use this cover to prevent roof leaks from developing.

 This system requires x1 Click Here

Required fuses, fuse blocks, bus bars and Circuit breakers:

​Battery Bank To Inverter/Fuse Block Main Fuse

100 amp Fuse and Holder 

150 amp Fuse and Holder

200 amp Fuse and Holder

250 amp Fuse and Holder

300 amp Fuse and Holder

The fuse should match your inverter. Use the link below to figure out what size fuse your inverter requires:
Fuse Size Chart Click Here

Fuse Block
Cell Balancer 

My favorite! This thing rocks. 

Click Here
Victron Energy Battery protect

​Low voltage disconnect and short circuit protection. I love these! Great for all systems. 

Click Here to Purchase

​Solar Panel Mounts:

Every vehicle is different, so check out my book and this page (click here) to figure out how to mount your solar panels

Battery Monitor:

1 Required for all systems. Tells you voltage of the battery and amp draw. Simply connects at the negative terminal of the battery bank.


Click Here

Required Tools:

Precision Wire Stripper

8-22 gauge wire
Click Here
Hammer Type Crimper
Can crimp up to 4/0 gauge wire, and it is much cheaper than other large wire crimpers. If you plan to build only one system, this is the tool for you. 

Click Here
Ratcheting Crimper
Allows you to crimp standard size crimp connectors.
 Click Here
​Standard Size Crimp Connector set
There are cheaper crimp connector sets available, but they are junk! Spend the extra money and buy a high quality set of connectors. The cheap chinese ones will fail and I have had it happen before. This is what I currently use:
Click Here
Large Size Crimp Connector Set
Use this set to connect large wires together, such as inverter or solar charge controller wires. 
Click Here

Other Accessories

12 volt USB charge strip
 Click here
46 Liter Dometic Solar Power Fridge
 Click Here
When connecting fans or lights or pretty much anything, use these quick connectors that are rated to 60 amps! I have used them for years for my rc airplanes and helicopters, but they are insanely useful for living in a rv. 


Click Here 
Super useful clippers. Use them to cut anything small.


Click Here