Power-Box or Solar Generator – Part #2

Power Box - solar generatorThis is the second article in a series written for you to make a power box, also known as a solar generator. But, this design is far above and beyond that of the normal run-of-the-mill solar generator or power box!

In the first article I went into the mission, restrictions, requirements, and some of the components that would be going into the unit.

In this article I will go into the nitty-gritty details and explain why and how I expanded the original design and intention. Before I do that, it would be a good idea for you to get caught up by reading the first article if you haven’t already read it. (and yes, I did some editing last night to clean it up.)

< click here to read the first article >

OK, let’s get rolling…

The first thing I realized that I really wanted a decent power supply that had adjustable vDC output. That gives you some flexibility when dealing with radio power demands and charging different types of batteries. But, that’s a different story, for now let’s get into the components and the build.

 { click on any picture to enlarge }
More components from the first article…

The power supply – I wanted to make sure I had plenty of power to run two mobile radios off of DC power from an MFJ-4230MV COMPACT SWITCHAC supply. I figured 25amps was plenty. I went with the MFJ 4230MV Compact 25a Power Supply.

There is plenty of power, solid piece of equipment, easy to use knobs, dials, and switches, plus easy to read amp/volt meter.

The build…
Step #1 –

I started with the empty Rigid toolbox with wheels. The box is incredibly sturdy and I love the wheels for moving the box around. Plenty of room inside for the battery and other components, and there is “stackability” to the system.  Which brings in a very sweet option later in the project.

To keep the battery in-place I added some Velcro to the bottom of the box. I secured it with Gorilla Glue in addition to the Velcro’s own stickiness that came with it. Then there Rigid Professional Tool Storage Systemis corresponding Velcro secured on the bottom of the battery. The battery weighs a whole lot so it really isn’t going to somehow just fall out of the box. The Velcro is used to keep it from moving around inside the box.

I used Gorilla Glue to secure the Velcro to the bottom of the box. When that was dry I placed the corresponding other side of the Velcro on top of that piece which had already secured to the bottom of the box. Then I put Gorilla Glue on that Velcro and set the battery on top of it.With the battery setting on it I figured I would get a great solid seal with the box, Velcro, and battery as it dried.

I let it set that way while I built the box. When it came time to remove the battery a couple of weeks later the Velcro was stuck perfectly to the bottom of the battery just like I wanted it to be. This was the easiest way I could think of to get Velcro on the bottom of the battery.

I wanted to ensure that I could get the battery in and out of the box (in case replacement was needed) without moving any other component. I also wanted to keep the components spread out to reduce PowerBox-000heat build-up as much as possible. It made sense to put the battery to the center-back of the box located as close to, and centered over, the wheels as possible for balance and ease of movement. The power supply and auto-switch mounted on opposite sides of the box made the most sense.

Originally I wanted the power supply on the inside-front of the box to make it easier to read the volt/amp meter. But, the bracket pretty much dictated where the unit was to be mounted. With the location and positioning of each component figured out, I moved on the to the actual installations.

Step #2 –

The MFJ power supply doesn’t come with a mounting bracket, and it is a little off when it comes to standard dimensions for mounting brackets. I don’t like reinventing the wheel if I don’t PowerBox-005have to, so I didn’t want to custom build a bracket. I took one of my spare Yeasu radio mounting brackets and added two small spacers to make it work for the MFJ power supply. I wanted the front display voltage/ampere meter to be easily read but I also wanted to maximize the airflow around and through the unit itself. Hence, mounting it on the left side of the box with the bottom facing towards the inside of the box to give it increased/maximized airflow.

Step #3 –

Next came the PWRgate auto-switch and its proper placement. I already had the left side used for the power supply. The front Ham In The Box - Super PWRgate PG40S by West Mountain Radioof the box I had decided to use for my Powerpole connections, meter, and power outlets. By default that gave me the right side of the box for the PWRgate. It was simple to find a decent spot and secure it to the side of the box.

Step #4 –

Then I ran my wiring from the MFJ power supply to the PWRgate. I used fuses on both legs of the wire coming out of the power supply.

PowerBox-007Once that was done I wired up from the PWRgate “out” connectors to a Powerwerx chassis mount for Anderson Powerpoles. That gives me two Anderson Powerpole outlets on the outside of the box that are easy to access. Since I was already using #10 wire I just did a simple splice connector for the second chassis mount Powerpole connection. I can’t imagine that running two radios, or other small electronics, would be more than the #10g wire could handle…splice connector or not.

Step #5 –

I wanted to complete one side of the power circuit to see if it was actually working so I went ahead and placed the battery in the box, wired the battery to the PWRgate “batt” connection. Next I connected the PWRgate to the Powerwerx chassis mount. All wiring is high quality 10g wire to prevent voltage/amperage loss. And, I used fuses again on both legs of the wiring between the battery and PWRgate. I really want to protect the PWRgate. That is a fairly expensive piece of electronic gear, and a blade fuse is cheap insurance.

PowerBox-202Notice on the battery terminals I used a standard battery connection terminal but with top-mounted posts. Then I made sure I used brass washers and wingnuts. I want as little corrosion potential as possible. And I want the best connection possible to pass the that precious power to the electronic components.

PowerBox-009Notice that I have connected the power outlet (Powerwerx Anderson Powerpole chassis mount) to the PWRgate with a single 10g wire. Then off of that wire I used a connector to splice in another 10g wire. Doing so gives me two sets of Anderson Powerpoles for connecting equipment such as mobile radios to the power box. The 10g wire is more than enough to carry the amperage; I used high-quality wiring from Powerwerx.com

Everything worked as expected. Yea!!

Step #6 –

At this point I tried to implement some logic…getting power to the battery other than through the PWRgate. So I installed another Powerpole chassis Anderson Powerpole Chassis Mount for 2 Powerpoles Sets (4 conductors)connection point on the left side of the front panel of the box. This would be my connection to external charging devices. Those devices could be solar chargers, a battery tender, or even another power box.

Notice that I ran the “power in” lines directly to the battery for the lowest voltage and amperage loss. I also didn’t want to run the risk of backflowing vDC through a piece of electronic gear. But, I did place a fuse inline to protect the battery from any surge coming into the box and vice-versa.

Step #7 –

I wanted to be able to monitor the battery and get a feel for usage rate, remaining operational time, etc. So in Powerwerx Panel Mount Digital Blue Volt Meter for 12/24V Systemscomes the Powerwerx voltage meter. It was a simple install direct to the front of the box. I located it in between a couple of horizontal structural pieces of the box. I used a State Of Charge charft for AGM Battery1-3/16” hole saw then used the standard plastic ring to secure the voltage meter to the box.


Step #8 –

As I mentioned earlier I wanted to have both a USB power outlet and a cigarette power outlet. The later provides a connection point for a wide variety of existing power options for various electronic and electrical equipment…including a power inverter.


Ham In The Box - Powerwerx Panel Mount Dual USB Socket 3 Amp Device Charger.Ham In The Box - Powerwerx Panel Mount Cigarette Lighter Socket Automotive Marine Grade

However, several weeks ago I did an evaluation on an alternative to the Powerwerx equipment. Not that I wasn’t pleased with the Powerwerx parts, I just thought they were a little pricey and I started looking around for something a bit less expensive. Well, I found an option that is just as good as, maybe even better, quality than the Powerwerx parts, and about 1/2 the price.

12v Technologies USB & power outletI placed a power outlet on either side of the voltage meter simply for a “balanced look”. What I also had to do was work the layout so the protective caps on the power outlets would open and not interfere with, or be impeded by, the lips of plastic on the box itself.


Step #9 –

I had originally thought to wire each of the power outlets (USB and cigarette) and the voltage meter directly to the battery. Then I started to figure out having to fuse each line, etc. Then I thought it might be better if I would go with one of my Powerwerx Red-Dee power distributors to move the power from the battery to the various outlets. Fuse the power line going into the distribution point. Then I would attach the two power outlets and the voltage meter to the distribution point and I would be good to go. But it looked like this…

PowerBox-015That is when I purchased a Powerwerx distribution unit to make it look much neater and way more professional. Oh, yeah, and it was way more functional to boot!

Powerwerx - PD4 power distributionPowerBox-203

In the next installment of this series of articles I will finish the build, talk about testing the powerbox, and how I made it even more functional with some great options and add-ons!

Related Articles –
Associated Articles –


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2 thoughts on “Power-Box or Solar Generator – Part #2

  1. Pingback: Power-Box or Solar Generator – Part #3 | A.H. Trimble - Emergency preparedness information for disasters and grid-down

  2. The work you do to help prepare us is such a blessing. I look forward each day to your blog. I have built this solar generator and love it.


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