From owner-qrp-l@netcom.com Wed May 3 17:23:54 1995 Received: from netcom23.netcom.com (root@netcom23.netcom.com [192.100.81.137]) by oucsace.cs.ohiou.edu (8.6.10/8.6.6) with ESMTP id RAA28248 for ; Wed, 3 May 1995 17:23:50 -0400 Received: by netcom23.netcom.com (8.6.12/Netcom) id JAA05296; Wed, 3 May 1995 09:44:50 -0700 Received: from mail1.digital.com by netcom23.netcom.com (8.6.12/Netcom) id JAA05279; Wed, 3 May 1995 09:44:44 -0700 Received: from us1rmc.bb.dec.com by mail1.digital.com; (5.65 EXP 4/12/95 for V3.2/1.0/WV) id AA11351; Wed, 3 May 1995 09:37:37 -0700 Received: from nac.enet by us1rmc.bb.dec.com (5.65/rmc-22feb94) id AA22302; Wed, 3 May 95 12:32:19 -0400 Message-Id: <9505031632.AA22302@us1rmc.bb.dec.com> Received: from nac.enet; by us1rmc.enet; Wed, 3 May 95 12:35:32 EDT Date: Wed, 3 May 95 12:35:32 EDT From: "Dennis, K1YPP, 226-5982" To: qrp-l@netcom.com Apparently-To: qrp-l@netcom.com Subject: Newsletter article (Long) Sender: owner-qrp-l@netcom.com Precedence: list Status: RO Here is the newsletter article on batteries and charging. This is the basis of the presentation that was given at this years Dayton Hamvention. We are working on having a place to post this stuff and then folks can FTP it etc. For those that cannot FTP we will set up an E-mail list and from time to time will supply newsletter articles etc. for clubs that are interested. 72' Dennis, K1YPP (PART I) BATTERY TECHNOLOGY IN THE 90'S "TO CHARGE OR NOT TO CHARGE, THAT IS THE QUESTION." By Dennis Blanchard, K1YPP JADE PRODUCTS INC. Engineer Batteries are a blessing and a curse, all in the same package. The choices are many, as are the sizes and packages. Unfortunately, this causes a delimma; which one to use, when to use it, and how to maintain it. The traditional choices for batteries are the NiCad, Dry- Cell, Wet-Cell and Gelled electrolyte Lead Acid and Alkaline. Some of the newer devices that are available now include the NiMH (Nickle-Metal-Hydride, a NiCad look alike), Lithium, Zinc-Air (Uses oxygen from the air) and "Smart Batteries". QRP operators use batteries more often than most amateurs simply because we tend to be more portable in our operations. Low power and small size is conducive to battery power. This is not to say that higher power is not possible using batteries, my own personal station consists of a Drake TR-7A that sees full power usage on occassion. The batteries of choice appear to be NiCad and Gelled- electrolyte. Unfortunately, when those NiCads are no longer usable they end up in the landfill, which is more and more becoming illegal. They're toxic. Pound for pound a NiCad can give one more current than most other portable batteries. The NiMH battery also has high current capacity and is less toxic, although not entirely. Their popularity stems from the fact that there has been a trend in Walkie-talkie devices for higher and higher power. We as Amateur Radio operators must ask ourselves if this is really the right direction to be going in. It has not yet been proven, but there appears to be some evidence that high power, particularlly at VHF and UHF (144, 220, 1296 MHz etc.) may be harmful. Microwave ovens operate near 1296 MHz and even the 500 Watt ovens cook very well, do we really want 5 watts next to the brain cells (20 dB less than the oven, of course the oven is shielded, isn't it?)? One need only look around at a Ham Convention to realize that the effects are already there, look at all the gray and balding heads, is this the result of too much RF too close? Just kidding. Seriously, we QRP operators should start pushing for lower power portable VHF/UHF hand-helds, the higher power really is unnecessary, particularly for line of site VHF communications. A question is commonly asked: "Can I charge my NiCad battery with a lead-acid (often motorcycle or small automobile battery) charger? The answer is no. The charging curve for these batteries is in no way related. There are devices on the market however that can be programmed to do both, I refer you to the piece that accompanies this article by Warren Dion, N1BBH, for the specific devices. The charger must accomplish several different things: Bulk charging, final charging and maintainence. Bulk charging is easy, force a high current into the battery until it nears complete charge. Now things get more difficult, we want to complete the final charging stage. This is where the "smart chips" make life easier. These chips watch the charging curve of the battery and as the slope of the curve changes they compensate the current going to the battery to level things off without overheating the battery or doing other damage. Once the final charging is completed the charger must now be smart enough to "hold" the battery at some state, ready for use, this is the "float" voltage. The floating state is usually at some preset voltage point. By referencing a voltage the charger doesn't care how big the battery is. If it were current referenced then the size of the battery would have to be known ahead of time, a 12 volt battery will always use the same charging points on the curve, different sized batteries could have vastly different currents to maintain them. The chip must be smart enough to monitor things once the charge is completed, and without exception they now all do this. A typical charger has a power line rectifier (or solar panel) which goes through some sort of filter to create a DC that may not be well filtered. Unlike a power supply, a hefty filter is neither necessary nor desirable. The ripple in the DC gives the DC a lower average value and as long as that value stays above some minimum point the charger will supply the needed current. If the DC is at some high average (which would mean a more complicated, expensive filter) then the heat sink will have to dissapate more heat to make up for the Voltage drop. The battery makes a pretty good filter capacitor, so equipment in use while the charger is running will not experience too much trouble with hum. Some filtering between the load and the battery can be used if this is a problem. The charger will use the DC from the rectifier to go through a pass device such as a pass transistor. In a situation where the battery is severely discharged the pass transistor may have to dissapate rather substantial amounts of heat. For example, a 12 V battery has been discharged to 3 volts. The charger bulk power supply voltage is up around 20 volts. 20V - 3V = 17 Volts drop. If the charger is to supply a 1 amp charge rate this will mean the heat sink and pass transistor will have to get rid of 17V x 1 A = 17 Watts. Some chargers (such as the Jade Products Inc Fun Kits...hows that for a commercial?) have a feature that looks at the battery and if it is below some pre-set level it will only trickle charge the battery until it reaches a higher voltage, for example 10.5 volts, before charging at the bulk rate. This now reduces the heat wasted to (20V - 10V) x 1 Amp = 10 watts, a substantial decrease. These circuits are easy to build but can be deceptively tricky to get running if something is not right. It is a circuit where the output affects what the input is doing and the input can affect what the output is doing, it is the traditional loop feedback circuit. One thing that has caught more than one builder is that the charger doesn't put out any real power until a battery is connected. If one puts a dummy load out there to test it, there will be very little output because the charger is looking for the condition of the battery and it is not going to charge a dead battery at full rate, it will charge at a trickle. This is very different from the typical brute-force charger found in a department store. Another feature that some charger chips employ now is the "burping" technology. In essence what this means is the charger puts a high current charge into the battery for some pre-determined time, for example 980 millisecond. The charger then takes a coffee break for about 10 Milliseconds and does nothing, then it reverses the charging voltage, thats right it hooks things up backwards for about 15 milliseconds and then takes a voltage reading on the battery to see where the charge state of the battery is. Why the reverse current you ask, simple, this reverses some of the chemical process that heats the battery up during heavy charging and stabilizes the chemical reaction. It "burps" the battery. I believe ICS corporation has the Patent on that one. Earlier a smart battery was mentioned. There is a standard starting to evolve around batteries to start getting batteries into some generic forms so that every device that seems to hit the market doesn't have a unique battery that cannot seem to be found anywhere. This standard will define the battery package, ratings and monitoring function. The batteries have a liquid crystal display showing its state of charge, current rate of use, and how much longer it can go, internal temperature etc. They also have an external bus connection to tell the user load this information, such as a computer or walkie-talkie so that the user knows when to give things a rest and do a recharge. This is a vast improvement over the present few seconds between the battery light on the walkie goes out and the time that the battery goes dead. One exciting developement in battery technology is presently available but hasn't as yet received much attention from the Amateur community. Ray-O-Vac Corporation has developed a re- chargeable Alkaline battery called the RENEWAL Battery. It can be recharged 25 times. I can see the reader response now...Ho-Hum. But wait, theres more! Most NiCad manufacturers promise that the NiCad battery can be recharged hundreds to thousands of times. Sure. They can, but that is under ideal conditions. What is the real world like? Most amateurs are very random when it comes to battery use. The walkie will sit for days, even months before it gets used. Good NiCads commit suicide at the rate of 1.5% per day and that's the good ones, in other words, they self-discharge at that rate. In 90 days the battery is dead. I have tested some inexpensive ones available from a major local electronics supplier and they died at 4% per day, they were dead in a month. This is why upon purchase one must charge the NiCad before use, it is usually technically dead because it has been sitting on the shelf since it was originally manufactured and charged. As mentioned earlier, NiCads are toxic, don't throw them in the landfill. Many states now have recycle centers for them. Contact the manufacturer if you don't know what to do with the dead ones. NiCads are particularly fussy about charging, and to some lesser degree, so are NiMH batteries. They don't like to be charged mid-cycle. They really must be discharged all the way to properly re-charge. Some of the new chips consider this and force a discharge if the battery is not fully discharged. The Maxim 712/713 series support this. If this is not done the battery will develope the "memory" problem that is so often spoken of. In reality more NiCads die from abuse than memory failures. Hobbies like RC cars are much nicer to the batteries, they tend to play with the car until it slows down because the battery needs charging, then PLUNK, into the charger with the batteries for a full recharge. Amateurs on the other hand operate in more of a "stand-by" mode where we want that walkie to be ready when needed. Unfortunately, trickle charges are not really that good for the NiCad, but then neither is sitting around unused, so it is a lose-lose situation. The RENEWAL battery on the other hand is a really long life battery. After a shelf life of FIVE years it is only discharged by 5%. It is almost like new! Not only that, it stores about three times as much power per charge as does the NiCad so it is still really useful. It has one limitation that the high powered walkie talkies don't like, it should only be used on steady loads of about 400 MA maximum and peak loads of about 1.5 Amps. NiCads can offer many times that. Still, in low power mode and for QRP operation this battery is a real winner. The RENEWAL battery charger is made by Ray-O-VAC and is available almost everywhere now. I have purchased one in a drug store and the other in a major retail store. Keep the booklet that comes with the charger, it is loaded with coupons for real price cuts on future purchases of both batteries and chargers. JADE PRODUCTS INC. is in no way involved with Ray-O-Vac Corporation. The above comments are my personal observations about this wonderful battery. give them a call or write for the Applications notes & Data Sheet on the RENEWAL battery line, it will convince you. Their address and some other petinient addresses follow at the end of this article. Now to dispel a few myths. The first one concerns setting a Lead-Acid automobile battery on concrete for an extended period of time. Common knowledge says this will kill the battery. My experience with this myth has uncovered the following scenario: A battery becomes spare because an automobile on its last legs decides to die on the first really cold day of winter. After cranking the daylights out of this engine that refuses to start it is decided to junk the car. Another reason it may become spare is because the automobile was in an accident. Since the battery appeared to be in good health when the accident occurred it is decided that the battery should be saved before the car is sent to the bone-yard. Unknown to the owner the electrical system of the automobile experienced a short circuit and the battery was discharged severely. Since this now "spare" battery has no immediate use it is placed on the concrete floor of the garage, or in some cases the cellar. There it sits, lost, forgotten and probably near dead from having the daylights cranked out of it before being sentenced to the concrete floor. Ohmic resistance of the plastic between the connection posts is in the billions of ohms. At twelve volts, to discharge the battery through this plastic would take longer than most of us have to live. The real reason the battery goes dead is because it was left in terrible condition and allowed to freeze a few times during the winter. Truly the death sentence. The myth about putting a block of wood under the battery will not help, proper charging and maintenance may have. Gelled Electrolyte batteries are finicky devils. One must carefully charge them. I can't begin to relate how many times I have people tell me they charge these expensive devices with very primitive chargers, such as those sold in the department stores. These charger are often used for this task and for a while they will work, however, the battery will not last long. As little as a 5% deviation from proper charging rates can shorten the life of this type of battery by half! Regular lead acid batteries are far more forgiving. It is fortunate that there isn't a branch of government to look after abused batteries, I suspect they would have a substantial workload. This previous scenario reminds me of the story of the fellow that decided he was going to experiment with feeding his horse saw dust instead of oats. He figured he would increase the proportion of saw dust a little each day and decrease the oats. At first he bragged about the experiment far and near and about how well it was going. After a while he didn't say anthing more about the experiment. A curious friend finally asked: "Hey Hank, whatever happened with your horse-saw dust experiment, how did it go"? "Well", replied Hank, " It went darned well for some time, but then all of a sudden that fool horse just up and died before I could finish the experiment!" Another myth concerns the short life of automobile batteries when used as backup batteries for repeaters or home stations. It is true that they will not last as long as deep cycle batteries if certain measures are not followed. One of the reasons the deep cycle batteries last longer is because they allow space under the plates in the cells for flakes of material to accumulate. This material falls there as a function of aging of the battery and if it piles high enough it can start to internally short the cells. There are also chemicals in the deep cycle battery to reduce this flaking action. One can prolong the life of the automobile battery by simply giving it a good "shake" once in a while to level out the flake accumulation. My personal station is a Drake TR-7 (Ah-ha, so K1YPP doesn't always run QRP!!! Honest, I do most of the time.). It uses an automobile battery and a JADE PRODUCTS INC. 1 amp charger and has been running this way so long now I have forgotten when it was installed. The battery is as good as new and it does get a shake every now and then. Hopefully this rather long winded piece has been informative and instructive. (If you think this was long winded, hook up with me on 3.720 or 7.120 MHz on Sunday mornings!). Batteries have been around for a long time and with electric transportation in the near future interest in them can only increase. Take good care of those devices and they will serve you well. Start letting the major walkie manufacturers know that you are more interested in long operating sessions than high power operation and force them to start using those rechargable alkaline batteries, they really are nice. 72' de Dennis, K1YPP SOME USEFUL CONTACTS: Ray-O-Vac Corp. JADE PRODUCT INC. OEM Sales and PO BOX 368 Marketing P.O. Box 44960 E. HAMPSTEAD, NH 03826-0368 Madison, WI, 53744- TEL: (603) 329-6995 4960 TEL: (608) 275-4694 FAX: (603) 329-4499 FAX: (608) 275-4973 RENEWAL Batteries Gel/Lead Acid Chargers RENEWAL CHARGERS Solar Chargers Chips and components (PART II) Batteries, Batteries, Batteries! or Chargers, Chargers, Chargers! by Warren E. "Bud" Dion All the world is going portable; heck, it already has! New and improved batteries are emerging. "Portable by Design" conferences are being held. Attention is focusing on how best to suit the new batteries to their new uses. Emphasis, long overdue, is being place on how to treat our batteries to provide life and capacity hitherto unknown. Charges are giving way to battery-management-systems. Calling these devices "chargers" is like referring to your PC as an "adding machine". A new day is dawning and the chip makers are not asleep. New chips do far more than the old-fashioned chargers, which often accepted overcharging and undercharging as necessary evils. Now they can look after your battery pack, maintain its health, even rejuvenate tired cells. Here are a few of the things they can do for you: 1. Wouldn't it be nice if you could hire a small boy to disconnect your battery from the charging source every second, read and store its open-circuit voltage, and get right back to charging? These chips do just that. 2. The provide charge termination, based on known battery dynamics. For NiCads this includes -V, which uses the slight drop in open terminal voltage to sense full charge. For NiMh cells they respond to the flattening-out of the O.T.V. (Output Terminating Voltage). 3. Offer charge termination's via battery temperature: +T. (Requires a thermistor) 4. Termination based on charging time. (Insurance, really) 5. Pre-discharge -- fights NiCad "memory" loss. 6. Pre-testing for temperature, state of charge, voltage, polarity, before the charging process can begin. 7. Full charging in as little as 15 minutes without damage. 8. Shaking -up (burping) the battery between charging current pulses; which cleans the bubbles off the electrodes, allowing more rapid charge acceptance. 9. Top-off, to get that last bit of capacity. 10. Maintain the charge 11. Some chips include a cool, chopper-type current- limiting function. Most leave it up to the user. It's a nifty function, though! 12. Most chips cost less than ten dollars. 13. The bad news is that no chip can provide all the above goodies. There are trade-off's. The EnChip is the most versatile, but at a very high price. Now let's back up and refer to the manual that came with your good ole HT. It told you to put your batteries on the charger for 14 to 16 hours, urging you to be sure that they were fully discharged before you start. Of course, they seldom were. How about the new cell that you just substituted for that bummer in the middle of the string? UGH! Why? Well, the 16-hour rate was low--and-slow enough to remain within the safe overcharge capabilities of the NiCads. Sort of like driving without a fuel gage, and a tank that takes all day to fill! A spare battery pack may become more of a convenience than a necessity. Inevitably, equipment developers are going to incorporate advanced battery management systems into their coming products. Also look for battery packs with built-in chargers, as well as thermistors. Maybe you are already working on such a project, but right now, poor ole hams who are tired of waiting 16 hours for their packs to come back to life can avail themselves of the advantages of the new chips. Everything from raw chips, and kits to finished assemblies are available. The accompanying table is a list of some of these chips with notes as to their respective attributes. Mfgr Part Batt. - + Pre- Curr Top Main- Notes Type V V check Limit Off tain Bench- BQ2003 NiCad Y Y Y Y Y Y 1 marq NiMH Maxim MAX 712 NiCad Y Y Y N Y Y MAX 713 NiMH ICS 1700A NiCad Y Y Y N Y Y 2 Philips TEA1101 NiCad Y Y Y Y EnChip ECS-II NICad Y Y Y Y Y 3 NiMH Pb-Ac Dallas DS 1633 NiCad Y Y 4 NiMH Pb-Ac Li Shore- ATC106 NiCad Y Y Y Y line NiMH Elect- ronic Notes: 1. The BQ2003 has chopper-type current limiting function. It also has a hardware initiated pre-discharge function. 2. The 1700A provides a unique, programmed reversed - pulse ("burping") feature. 3. Looks like it does everything, but is expensive. Made in Austria. 4. Interesting, three-terminal TO220 device. User- programmed via a single, serial pin! GENERAL: A. Most, if not all, chips include max-time limiting function. B. Blank cells in the above table echo the author's mind on the respective item.