Homemade Portable Solar Panel Built

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April 22, 2019, 05:58:37 pm

Parts List
Renogy Solar Starter Kit . $95

Renogy MC4 Tool . $5.50

Super Cloud Extension Connector Terminals. 1Ft . $9.00

Renogy-10Ft-Adaptor-Female-Connectors . $21.00

Construction Note
I knew it but its worth repeating Lazy Daze is not know for using too much wire. The hardest part was getting the battery out so I could attach the extension connector to the plus battery terminal. Once the battery terminal connectors where in place the rest of the construction was plug, screw down, and play.

Why and what not......
I took on this project to learn and teach myself about solar power, solar panels and solar controllers. As we all know there are a lot of very 'helpful' folks on the internet. Sorting the facts from the alternative facts is a full time job.
My project by its nature is a throw away. I beleive ALL lesson cost money. Thank god for the cheap ones. My plan now is the use this setup in the 'real' world so I can learn what improvements I'll need.

Lesson learned so far.
MPPT and PWM -- the difference is more to do with the use and application is what is better. They both will produce, in the same price range the same amount of power.

Cost -- the price of a controller will get you more bells and whatnot but they all seem to produce the same amount of power.

The controller you SHALL have should be based on the amps your solar panels will be producing. I.E. 10 amp controller for a set of 10 AMP panels etc.

All controllers produce large amounts of heat. Get one will a good heat sink.

Edit note: I added a new image of controller 'dressed' up. (april 28,2019)

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Re: Homemade Portable Solar Panel Built

Reply #1 – April 22, 2019, 06:29:58 pm

Quote from: colddog - April 22, 2019, 05:58:37 pm

MPPT and PWM -- the difference is more to do with the use and application is what is better. They both will produce, in the same price range the same amount of power.

Cost -- the price of a controller will get you more bells and whatnot but they all seem to produce the same amount of power.
All controllers produce large amounts of heat. Get one will a good heat sink.

MPPT will transfer more power from the panel to your applications than PWM, particularly when your battery is at a low state of charge. More money can either get you more features, or a more rugged design - opt for the latter. A good design should produce little heat. My Sunsaver MPPT doesn't get warm to the touch, and has no display other than a few LEDs. The cost is in the quality.

Steve

Re: Homemade Portable Solar Panel Built

Reply #2 – April 23, 2019, 02:56:47 am

"My project by its nature is a throw away. I beleive ALL lesson cost money. Thank god for the cheap ones. My plan now is the use this setup in the 'real' world so I can learn what improvements I'll need."

That's a good strategy: build an inexpensive setup to learn what you need to make a really good one. Make mistakes, but make them cheaply. Smart.

"the price of a controller will get you more bells and whatnot but they all seem to produce the same amount of power."

I can't agree. An MPPT controller will milk significantly more power from the same panel than a PWM controller. In my fifteen years of experience I've seen gains between 10% and almost 30%. Whether that increase in power is worth the higher cost of an MPPT controller is up to you, but there's no question that MPPT gets you more from the same panel.

"I.E. 10 amp controller for a set of 10 AMP panels etc."

I'd rephrase that to "Your controller should be rated for at least as many amps as your panels produce." Since it's pretty common to upgrade solar arrays by adding panels, I wouldn't buy a controller that was sized exactly to my first set of panels--I'd get one with "room to grow."

For example, Victron's MPPT 75/15, for about a hundred bucks, is an excellent place to start. It'll get the most possible juice from your panel(s) up to 15 amps, doesn't run hot, and has a built-in Bluetooth capability that works with Victron's free iOS/Android/macOS/etc. apps to provide better information than any wall-mounted display I've yet seen... shown wirelessly on your phone, tablet or laptop.

"All controllers produce large amounts of heat."

Again, not necessarily. Cheap controllers waste energy, which is released as heat. Victron's small to medium MPPT controllers (I use both their 15-amp and 50-amp versions) don't even have external heatsinks, but my thermal camera photos don't show them running hot--merely warm.

Re: Homemade Portable Solar Panel Built

Reply #3 – April 27, 2019, 02:33:20 pm

I agree that an MPPT controller will provide more current to the battery under most conditions, but one thing never mentioned is the overhead of the controller which is higher in an MPPT because of the additional electronics it uses. While its not much, on a very small system (like a single 50 watt panel) it could be an issue. The only other negative of MPPT is the price. If cost is an issue, you would get better results spending the additional $100 on another 100 watt panel than a MPPT controller.
Another thing to consider if you are using portable panels is where the controller will be located. Renogy sells a quality 20 amp PWM controller that is waterproof for $60 (less when on sale). I'm not aware of any MPPT controller that is waterproof; the advantage is that you can mount it on or near the panels and not worry about a midnight shower.

Rich - former 2000 MB - now Bullet Crossfire trailer pulled by a Chevy 2500HD - Birch Bay, WA - 200 watts portable solar with a Renogy Voyager controller hinge mounted on one of the panels and not worried about PNW weather.

Re: Homemade Portable Solar Panel Built

Reply #4 – April 28, 2019, 06:13:26 pm

Review of controllers

https://youtu.be/kF_cVEYxj3E

But back to my homemade system. On first test all seems to work. I'm getting good voltage 14.4 or so. Since I'm only leaving the system up for at most 1 hour I'm not sure what the result will be on the life of my installed AGM's. As the AGM's are over 5 years old I'm willing to experiment. We'll be camping soon so I will have more data. If it fails (smile)...... I'll just be a bit smarter.

glen

Re: Homemade Portable Solar Panel Built

Reply #5 – July 13, 2020, 10:05:48 am

Update......

I've added a new solar panel and controller.

1.Victron MPPT 75/15

2. Rich Solar 100 Watt

The solar panel was pick basically because the Renergy panels were sold out when I wanted to upgrade.

The Victron SmartSolar was purchased after must internal debate. The question came down to what size. Since this will only be a one maybe two panel setup I went with 75 volt 15 amp device.

Construction Notes.
Soooooo I removed the old Renolgy PWM controller with no problems. The small issue was the Victron changes the order of battery and solar terminals. Being 'smart' I marked all the cables (plus and negative). I did enjoy a lesson on Murphy's Law. Wired the system and dress the cables. Did the smoke test -- enjoyed listening to a rather loud bang. Between you and me I didn't know a 20 amp fuse could made that loud a noise. After a few moments of explaining to myself what a smart person I was I replace the used fuse with a new one. Put the solar and battery cable in the connections that Victron suggested they should go redid the smoke test --- all is happy in the Baxter world again.

glen

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Re: Homemade Portable Solar Panel Built

Reply #6 – July 13, 2020, 11:41:56 am

Sounds good, Glen. One thing I noticed: your controller appears to be floating your batteries at 13.79 V. Most AGMs prefer a much lower float voltage (e.g., for Lifelines the recommendation is 13.3 V at 77° F--see attached chart). You may want to change your controller's settings to avoid overcharging.

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April 22, 2019, 05:58:37 pm

Reply #1 – April 22, 2019, 06:29:58 pm

Reply #2 – April 23, 2019, 02:56:47 am

Reply #3 – April 27, 2019, 02:33:20 pm

Reply #4 – April 28, 2019, 06:13:26 pm

Reply #5 – July 13, 2020, 10:05:48 am

Reply #6 – July 13, 2020, 11:41:56 am

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