Searching for the Holy Grail of Charger Setups

Written by Greg Gimlick Electrics Column As seen in the June and August 2017 issues of Model Aviation.

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In this column, I plan to discuss finding and building the “perfect” charging setup. This will naturally be different for each person depending on his or her goals and needs, but I hope it will give you an idea of how to quit buying charger after charger before deciding which setup is right for you. I’ve also received a couple of answers to some battery questions that some of you have asked.

John From Revolectrix Responds

Some of you have been pressing me for answers as to why we should store batteries at storage levels and not just leave them fully charged. John, a battery engineer with Revolectrix, took the time to answer a list of questions that I’ll cover now and in the next few columns. This month’s answer concerning battery storage levels is: “Storing at high voltage makes the electrolyte react with the cathode over time and pollutes the anode, which leads to higher internal resistance (IR) and loss of capacity. Why does this not happen to cellphones? Because the coatings of anode and cathode are thicker for low C-rate cells.” I’ve promised not to wear John out with questions, but because he designs these things, who better to ask! Thanks for your questions and thanks to John for taking time to help us out with insider knowledge.

Define Your Charging Needs

Most of us waste money buying various chargers because we don’t stop to think about what we’re going to charge—not just the immediate need, but down the road, too. Take time to figure out what your future plans will be. If you’re never going to go beyond smaller 3S battery-powered airplanes, you don’t need to buy a charger that will do multiple 6S packs at maximum charge rates. If you might want a larger airplane in the future, think about getting that larger, greater capacity charger now, even if you’re not fully exploiting its power. If you’re not going to go beyond the smaller packs, decide whether you might want to parallel charge. Doing multiple 3S packs at one time is a handy capability, and one I regularly use.

The holy grail of charging setups that the author will build. Only the top box has charging gear in it.

Available Options

There are so many options that I can’t cover them in 12 issues. Look around at your club field and see what people are using. Check out a fly-in, if possible, walk around the pits to look at various setups, and ask other pilots what they think. You’ll be surprised at how candid they will be—and maybe even shocked. There are very few “bad” chargers around right now. Prices cover a wide range, but I always try to find a charger with a good reputation for capability and service. I want a company that I can call and I want to be able to talk with someone who knows the equipment and can repair it if needed. There are several companies in the US that can do both, and I encourage you to consider those products.

My Case

My needs have changed throughout the years, although my first choice of a charger setup still covers everything nicely. By “charger setup” I mean a box with a self-contained power supply, which I can easily close up and travel with. I want it to protect my valuable charger and be able to carry a few adapters, etc. The problem I have had with previous setups was the amount of wire and accessories I needed to disconnect and store before closing up the unit. My goal this time was to find a setup that was completely enclosed and contained. I wanted something neat and tidy, where wires wouldn’t get caught in the top after it was closed.

The Choice Is Made

At last year’s Toledo Show: R/C Model Expo, I researched all of the choices. Suddenly, the clouds parted, the sun shone through, and the angels sang—there it was! Okay, maybe I’m exaggerating slightly, but when I found the BumpCharger booth, I knew I had found my answer—and my next project!

BumpCharger offers a more modest setup for pilots. You can easily find something for every budget or need.

This was an incredible find and the process of assembling my box didn’t involve trying to design something from scratch; it was already done. These setups are planned around a commonly available box from a local Home Depot. They offer multiple options for the design and build. You can order: • Complete customized setups that are fully assembled and tested. • One of several prebuilt standard setups. • Only the components if you want to build it yourself. • Almost anything in between!

My Path to Enlightenment

I already owned a Revolectrix PowerLab 8, a parallel board, and a Bump Controller, so I knew I would build my setup around that. I also wanted two separate parallel boards to charge different packs at the same time. I had planned to buy another charger, but because the Bump Controller can handle up to four chargers, I opted to buy another PowerLab 8 and parallel board. These can be purchased from BumpCharger without an additional markup, so I ordered them with my other gear. The next step was configuring the top deck the way I wanted. Decks come in all sorts of configurations, depending on the gear you have, or you can design your own layout and have it cut. It turned out that the configuration I wanted was one of BumpCharger’s standard offerings. My plan was in motion, and I began the ordering process. One of my Christmas presents was a full stack of RIDGID toolboxes from Home Depot, so I was all set.

The Ordering Process

After you’ve decided on the charging equipment you’re going to build into your setup, you can begin working through the ordering pages. These are laid out to guide you and help you think about things you might not have considered. I found several options that I decided to add and I wouldn’t have thought of them up front without help. Each time I found something, such as a special switch or mounting plate, I checked the internet to see if I could do better on my own. In each case, I found it was as economical to buy it from BumpCharger. The upside is knowing that the people at BumpCharger have used the gear and it would fit. I did not want to find that I had bought a number of items and they wouldn’t fit!

The author’s setup is built around two Revolectrix PowerLab 8s, a Bump Controller, and Revolectrix parallel boards.

As I compiled my list of equipment, I corresponded with BumpCharger and asked questions or made comments about how I intended to use the gear. The people there were a big help, telling me why I might or might not want to do something a certain way. One suggestion was to get the basic box from the company instead of modifying one of mine. I could do it myself, but for the minimal expense of having BumpCharger do it, I knew that the right flanges would be trimmed off and that all of the options had been tried. The biggest help was suggesting that I go ahead and order the base mounting plate. Wow, this well-thought-out piece made the final build so much easier. In the end, I ordered the box from BumpCharger with the mounting plate. By doing this, the company also fit the top deck I ordered, so I didn’t have to work out the mounting brackets, etc. I suggest that you follow suit to make your life easier. Check out the BumpCharger website and study the information there. My build will make a lot more sense to you and you can begin to figure out how to do your own.

BumpCharger

After I decided on the format of my setup, I added the second charger and parallel board. I ordered the mounting plate for the bottom of the box along with the top deck. It was trimmed and fitted by the staff at BumpCharger.

The box looks like this when you start. Most of it comes out or is trimmed during the build.

The scariest part of the build was trimming the feet on the Revolectrix CellPro PL8 chargers so that they would fit in the box. I felt better when I found that doing so would not void the warranty. It was an easy task because the case is plastic. I ordered the switches and power supply from BumpCharger because it was easier and as cheap as if I sourced it myself. The benefit was that the power supplies came modified with one of them isolated so that they could be run in series.

The author chose the custom bottom plate to mount his PL8 chargers and power supplies.

If you connect two supplies in series without doing this modification, you will ruin them, so be sure that you understand how to do this if you opt to do it yourself. Study the many references online before trying it. When the box arrived, blue tape marked the exact spots to drill in order to mount the AC socket, switch, and EC5s. The company sells an effective mount for the EC5 plug. I also mounted a 12-volt output socket on the side using Anderson Power Poles (APP) and used Anderson AutoGrips from Hardened Power Systems. This is by far the best way I’ve found to mount APPs to any surface.

The top deck is one of the standard setups that BumpCharger offers. Here, the gear is shown mounted.

Wires and More Wires

There is a lot going on inside this case and everything has a wire. Before bolting anything in, make sure that you’ve breadboarded it and you fully understand the wiring. Don’t skimp on quality or gauge. If you have doubts, contact BumpCharger and ask someone on staff. I used 10-gauge wire throughout. The company has a couple of wiring diagrams online and one exactly fit my setup.

Everything is wired and ready for the top deck to be installed. This is a lot of wiring! It must be double- and triple-checked before powering up for the first time.

Label everything! I found that the studs on my switch were slightly long, so I trimmed them to make final installation easier. Check and double-check everything before plugging it in for the first time. Neatness counts as you wire and connect things. Watch for possible shorts and insulate everything.

The Result

My box is completely self-contained. There are no external wires to work around or connect except for the AC cord. I can open the box, plug it into a wall socket, and simultaneously charge up to 12 8S LiPo battery packs. I can also put the switch in one position to provide an external 24-volt outlet via the EC5 connector on the back. There is a constant 12-volt output on the side via an APP. If I need to power the setup without AC power, I can put the switch in the DC position and supply 12 to 24 volts from any DC source through the EC5. This bypasses the internal power supply and powers the chargers.

This is the ground isolated power supply. One of the two power supplies must be isolated!

The reason I bought the stack of boxes was to install two 12-volt deep-cycle batteries in series in the bottom box to power the setup when I don’t have AC available. The box is on wheels, so it’s easy to move. There is still room to add a couple of USB ports, too!

Final Word

Figure out what your needs are and build a setup to last. Check out BumpCharger.com and look at how many choices there are. You can build as much or as little as your needs and budget allow. I also downloaded the app for my Samsung Galaxy Tab tablet so that I can control it remotely via Bluetooth. I chose a proven setup, but the world is wide open for you to build your own holy grail of charger setups! -Greg Gimlick [email protected]

Sources:

BumpCharger www.bumpcharger.com Revolectrix USA (301) 798-2770 www.revolectrix.com Hardened Power Systems (800) 328-9315 www.portableuniversalpower.com AMA Flickr photos www.flickr.com/photos/modelaircraft Home Depot (800) 466-3337 www.homedepot.com