How to Design an Off-grid Solar Power Array Wire Configuration

0:42 3 important variables
1:12 EPever MPPT
3:19 24V 1050W Example
4:21 12V 1050W Example
5:34 MPP LV2424 Example
7:18 OCPD for multiple strings
10:13 12V PWM Example

If this video is confusing, watch this:

How to calculate OCPD for PV strings:

Does off-grid solar confuse you? Check out my DIY friendly website for solar system blueprints, recommended components and much more!

Join our DIY solar community! #1 largest solar forum on the internet for beginners and professionals alike:

Check out my international best-selling 12V off-grid solar book (Amazon affiliate link):

Coupon codes and solar distributors I recommend:

-Rich Solar: No coupon code needed here because they have the lowest prices around. High quality solar equipment and solar generators: Megasite! They have everything you need to build any size system (
10% off code: WillProwse (
10% off code: diysolar

-Watts 24/7: Best deals on all-in-one solar power systems, with customer support and distribution here in the USA:

-Signature Solar: Great deals on large solar panels in bulk and server mounted LiFePO4 packs:

-Practical Preppers: DC Mini Split Air Conditioners and Sol Ark Inverters! If you want the best of the best, find it here:

My solar equipment recommendations (Constantly updated, unlike my videos! Check here first):

Plug-n-play Lithium Batteries:

Solar Panels:

DIY LiFePO4 Batteries:

Raw LiFePO4 Battery Cells:


Off grid Inverters:

LiFePO4 Battery Chargers:

Solar Charge Controllers:

Solar Panel Mounting Guide:


Battery Monitors:

Favorite Tools:

12V fridges:

-DIY Solar System Packages-

Plug and Play Systems:

400W Starter System:

400W Starter System w/ Alternator Charging:

800W System:

DIY LiFePO4 System Design:

Contact Information:
I am NOT available for personal solar system consult! No exceptions! All emails asking me to design or help with building your system will be deleted. If you are a business or youtuber and wish to contact me, this is my direct email:

Join the forum at if you wish to hang out with myself and others and talk about solar

Affiliate information and disclaimers:
Every video includes some form of paid promotion or sponsorship. Links in description are affiliate links. My videos are for educational purpose only. Information is subject to change/update at anytime. Electricity is DANGEROUS and can kill. Be smart and use common sense 🙂

DIY Solar Power with Will Prowse is a participant in the Amazon Services LLC Associates Program,
An affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to
FTC Disclosure Statement:
Some links on this youtube channel may be affiliate links. We may get paid if you buy something or take an action after clicking one of these.


  1. Very informative video. Answered a bunch of questions I had regarding solar array layout/wiring config. Thanks Will.

  2. Please be careful, most of the wiring in the back of the solar panels are rated for a max current of 20 amps (AWG 12 ) and NEC recommends using only 80% of that for a total of 16 amps. Putting multiple strings in parallel will increase the current and you can have a potential fire on your roof.

  3. Man I need your help. Did things a little backwards and bought my batteries first due to one hell of a deal. Bought 8,12 volt 145 amp hr. Now I need recommendations on panels and inverter/charger.

  4. It would be nice if they were self current limited that way you could overbuild the panel for consistent output in various weather.

  5. Cool, cool, cool 😎 now if I can just remember the difference between parallel and series…Just do the math he says. Know what I'm mounting on the side of my first diy system? Fire extinguisher. News @ 11…Love it man, keep it up!

  6. I can bend up sheet metal all day, but this electric, like he said can kill u, an for that reason I'm not confident an can't Grasp it at all

  7. I have 36v 140w 10 solar panals.i needed to get 60v for my mppt charger controller . 2s 5p or 5p 2s most sutable.

  8. I am new to the off grid solar systems. I have installed a system that is working well for me. I would like to ask that you give me your opinion and any recommendations for improvements. Would you be willing to do that for me?

  9. Blah blah blah, until solar can run the entire house AND a/c, for less than buying the house…… is dead to me. Lol

  10. So my three 200 watt solar panels (nominal 12 volts) in parallel to my Morningstar Pwm tristar 45, charging my 12 volt battery bank on my boat is ok. I think

  11. Hey I have 3, Hyundai 36 volt 260 Watt 8.9 amp solar panels what charge controller should I use and how should I connect these such as (series or parallel)

  12. Will, can you make a video for a hybrid on-grid solar system, I'm thinking of getting solar but want a system that if the grid goes out for whatever reason I can shut off that part. Been told that if grid goes out your system shuts down so no power goes to the grid, would like to get a on / off grid, is this possible?

  13. i havent found and good videos on 48volt systems with my 6volt batterys videos took me awhile but i figured it out working on a video now thanks i learned alot from your videos all basics and used it all to make my sysyem works great the systems i see are just to small for normal houses saved myself thousands of dollars got to love utube

  14. Every video you make does not have any annoying music, is straight to the point, fast and clear. That is so hard to find on YouTube!
    Thank you for that! Keep on making great content.

  15. im doing 3S on the first array 135volts 1050w 9a and 2S2P on the second array 90V 700W 18A. what you said about the disconnect for checking dc voltage is very SAFE. your suggestions for fuses is also SAFE and to check series current up to 100 A DC you need a $100 meter from the box store. this is a minimum amount of watts. when she plugs in at the campground she gets 50A x 240volts or 12000 watts, 30A at 120v is only 3600watts (most trailers) still more than the 1700watts she will have off grid. i taught an electrical class at TA&M and you are one of the best i have ever seen for explaining something you cant see. thanks again.

  16. thank you so much, i got your book online but still had questions. you answered them all today. i am helping my daughter with her Shamrock Skoolie. 3 panels 1050watts and 4 panels 1620watts. i have 14215BN and will purchase another this week. She has 24v Lifepo battery system and the 8s BMS controller came in yesterday. i will feed the 3 panel array into it first and then add the 4 panel array. She has everything except a swimming pool for this bus. Thanks again.

  17. What is url for your website Want to buy some inline fuses for my solar array. Using your configuration but with 4 -300 watt panels

  18. Are u related to the guy who does the woodworking for mere mortals course by any chance? Just curious. Yall have the same cadance when speaking, which for some reason, seems to be quite conducive for driving in information to my brain lol. Keep it up lol

  19. Hi Will!
    I really enjoy your videos and have learned a lot however, you made a mistake with your voltages and wattages when putting then in series and parallel. You do not add both values, it is always one or the other. In series, you add the voltages together but the wattage stays the same (Example: three 45v/100 watt panels in series would be 100 watts @ 135v. Those same panels in parallel would be 300 watts @ 45v).

  20. Do you have a solar charging system recipe generator? If not I think you could sell that. Type in the required total load output desired and get the specs for each component up stream. Great video.

Leave a comment

Your email address will not be published.