Technology reporting: vaporware vs. hardware
Red Scholefield | [email protected]
MA has been taking some hits on modeling forums for not being proactive in covering emerging technology, particularly in the field of energy devices. “You’d think MA would have been on the ball and getting this out,” read one such post. “I guess they don’t have anybody there with enough get up and go to keep up to date on stuff like this.”
That opinion was in reference to an article about paper-thin batteries made from algae that some of the popular science media made public. Almost any institution with a chemistry department and a half-dozen test tubes is working on such projects, looking for the Holy Grail in energy—but, more realistically, for fat government or industrial grants to support more research.
Following are comments in one such battery-breakthrough article from the December 21, 2009, MIT Technology Review:
“A ‘digital quantum battery’ concept proposed by Alfred Hubler, a physicist at the University of Illinois at Urbana-Champaign, could provide a dramatic boost in energy storage capacity—if it meets its theoretical potential once built.”
If you are interested in developments that have little chance of becoming usable in our hobby during your lifetime, all you have to do is Google "Flexible Energy Storage Devices." You will find at least 60 pages (I gave up at that number) on the subject.
Another technology not to get too excited about is lithium–sulfur batteries. Following is from the article "Revisiting Lithium-Sulfur Batteries," from the May 22, 2009, MIT Technology Review:
"Lithium-sulfur batteries, which can potentially store several times more energy than lithium-ion batteries, have historically been too costly, unsafe, and unreliable to make commercially. But they're getting a fresh look now, due to some recent advances. Improvements to the design of these batteries have led the chemical giant BASF of Ludwigshafen, Germany, to team up with Sion Power, a company in Tucson, AZ, that has already developed prototype lithium-sulfur battery cells.
"'Compared to existing technologies used in electric vehicles, the plan is to increase driving distance at least 5 to 10 times,' for a given-size battery,' says Thomas Weber, CEO of a subsidiary of BASF called BASF Future Business. Other experts say that a threefold improvement is a more reasonable estimate."
Lithium sulfur dioxide batteries used in aircraft emergency-locator transmitters at one time had the disconcerting habit of spontaneous ignition. Add to that other "exciting" breakthroughs, such as micro fuel cells applicable to modeling applications, and you can dream on.
Cold fusion anyone? How about running your car on water? What about carburetors that will get you 100 miles per gallon? Remember those personal aircraft in every garage that we were promised in the late 1940s?
So at the risk of not keeping you up to date on the latest vaporware, I purposely report only on those "breakthroughs" I can touch and get samples to test.
Nickel-Zinc Rechargeable Batteries
This antique electrochemical couple has been around for a century or longer. Thomas Edison originally conceived of nickel–zinc (NiZn) batteries for use in high-power, high-energy applications.
However, a severe flaw limited these batteries' use: dendrite formation during recharging. Dendrites reduce the overall performance of the battery and can even lead to shorts, rendering the entire cell useless.
Atlanta, Georgia–based Air Energy Research spent more than 10 years researching and developing zinc-air batteries (hearing-aid technology). They convert oxygen to electricity to power cellular phones, pagers, handheld video recorders, and other small electronics. Unable to bring the product into production, the company folded. Now PowerGenix, another player in the battery market, brings us rechargeable NiZn that might show some promise.
I received a dozen 1.6-volt NiZn AA rechargeable cells (1500 mAh) to evaluate, along with the consumer charger. PowerGenix also offers a Sub-C NiZn in 2000 mAh.
Before PowerGenix, in partnership with Hunan Corun Hi-Tech Co., Ltd. (a China-based battery manufacturer), could make NiZn battery chemistry available, it needed to solve the technical problems associated with the instability of the zinc electrode in the rechargeable cell. The company claims that the cornerstone of this solution is in electrolyte formulation that reduces zinc solubility and prevents dendrite shorting problems.
The PowerGenix NiZn batteries cost roughly the same as other rechargeables. They are listed on Amazon.com for about $2.50 per cell. This battery, with its higher cell voltage, has close to 50% more energy density (Wh/kg) than Ni-Cd or NiMH batteries. Cycle life is reduced, while long shelf life (charge retention) is touted.
Charging NiZn batteries requires a constant-potential, current-limited charger, much the same as Li-Poly cells do—just with different voltages and current limits. The limit is 1.9 volts with a 1C current limit; charge should terminate when the current drops below 75 mA.
The charger that PowerGenix offers accommodates one to four cells, charging individually and taking one hour for one to two cells and two hours for three to four cells. Because they are a constant-potential system, cell balancing should be employed, as with Li-Poly packs.
I have been unable to determine the impact of deep discharge on NiZn cells. Until that is known, it is suggested that you don't take them lower than 0.9 volt. As with Ni-Cd and NiMH cells, reversal should be avoided.
In receiver packs, using four NiZn cells gives you a nominal voltage of 6.4 V with a high just-off charge of 7.2 V, which would dictate a regulator for most receivers in which 7.2 V could exceed the limit. A transmitter normally powered with eight cells would require only seven NiZn cells.
The catch in both of these situations is charging. There are currently no units I know of that will accommodate charging and balancing NiZn packs. I see no reason why chargers such as the Cellpro Multi-4, with its open programming architecture, could not be upgraded to charge and balance four-cell packs.
On the other hand, a seven-cell charge/balance unit has yet to be offered for NiZn. One workaround is to use an eight-cell holder in which the cells can be individually removed and charged with a dummy cell (made from a 1/2-inch-diameter wood dowel with jumper wire), using the consumer four-position charger that PowerGenix sells.
The Jigs Up soldering tool
If you have trouble soldering battery connectors, The Jigs Up soldering tool might relieve your pain. Michael Howell submitted the following information.
Gregg Paxton developed this tool for his friends to use while soldering connectors on their speed controls and for other RC electrical needs. They were using the old methods of needle-nose pliers, tweezers, etc., to hold the hot wires while trying to make good solder joints.
The Jigs Up ends all of those problems. It is machined from bar-stock aluminum, with spaces that hold a variety of connectors such as, but not limited to, Deans T-plugs, Deans two-pin plugs, and 2 mm and 3 mm bullet plugs.
The face of the tool has recesses and holes for holding various electrical connectors. A thumbscrew through a 1/2 x 1/8-inch strip of aluminum is used to facilitate the clamping action to hold the plug part to be soldered. The machining and finish are excellent.
A hot soldering iron is needed to accomplish a good, strong solder joint. Paste flux is my favorite way to solder, even though I also use flux-core solder.
(Editor's note: RadioShack 60/40 Rosin Core Solder, item 64-008, serves our electrical soldering purposes well.)
Make sure that the soldering iron you use has enough mass at the tip to assure good heat transfer. A 1/4-inch-diameter chisel tip with a 40-watt iron is recommended.
The wires must be tinned first, and you must also tin the plug parts. This keeps from overheating the metal portion of the plug and melting the plastic portion.
With The Jigs Up, soldering to your connector is greatly simplified. Not only does this tool act as a clamp, but it's also a heat sink.
If you need to solder any plug to a battery, my preference is to slip on a piece of heat-shrink tubing that is longer than the plug. This acts as an insulator against accidental shorting across the plug's terminals.
Soldering the vertical post on the connector is easy and quick if you turn The Jigs Up on its side. I have found this tool to be a worthwhile investment of time and money when performing these important and necessary tasks.
FMA Direct PowerLab 8
FMA Direct has released another breakthrough charger: the PowerLab 8.
Pushing 1,000 watts of power, the company addresses the needs of the electric flier who wants to take things to the limit. This unit has all the features one could want in battery maintenance. Priced at approximately $250, this charger should be shipping by the time you read this.
PowerLab 8 is the most advanced battery maintenance system I have seen. Open architecture presets allow for customization of any user preset, including show/hide presets on unit, preset naming and editing, and as many as 100 parameters that can control how presets are displayed.
This unit also has charging/discharging/cycling parameters associated with particular batteries and/or charging strategies. It includes 25 user preset banks preloaded for most major battery types/chemistries and 50 library presets.
This only scratches the surface of the capabilities and features this charger offers. Space prohibits my including a full list, but you can see all of the details at the FMA Direct website (see Sources).
Club visit: Central Florida Sport Flyers
I had the privilege of being a guest of the Central Florida Sport Flyers during the Christmas holiday. This club is heavy on electric power, with a first-class charging facility. It is fortunate to have AC power at the site to operate a heavy-duty 12-volt system.
I included a photo of the club's president, Brad Paul, flying a 1/4-scale Balsa USA Nieuport 11. It is powered with a Scorpion 2516 outrunner motor and has a Phoenix Ice HV 60 ESC on an 8S2P A123 M1 cell pack.
The AMA forum on its website is up and growing. Stop by for discussions and to join the fun!
Sources
- PowerGenix
(858) 547-7300 www.powergenix.com
- The Jigs Up
- FMA Direct
(800) 343-2934 www.fmadirect.com
- AMA forum
- The Battery Clinic
12219 NW 9th Ln. Newberry, FL 32669 www.hangtimes.com/redsbatteryclinic.html
Transcribed from original scans by AI. Minor OCR errors may remain.
