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Practical Lead-Acid Battery Tips
by Wesley Cardone
February 23, 2000
The lead-acid battery, developed in the nineteenth century, remains a primary source for electrical energy storage today. It is used in applications ranging from intercontinental ballistic missile silo energy storage to providing operational power for golf carts. Battery technology has vastly improved since the days of North America’s old west resulting in a very wide variety of options to consider when acquiring a battery. There are also a lot of "ins and outs" to be aware of in maintaining them. This article will explore many of the little known nuances of these batteries and provide the reader with a number of helpful tips.
Measurement of battery charge is usually accomplished by two means: measurement of its terminal voltage (no-load); and measurement of the specific gravity of the electrolyte. A terminal voltage reading of 12.6 volts indicates a full charge, 11.7 volts a low charge, and 10.5 volts is an indication of an exhausted battery. Before taking a terminal voltage reading be sure to draw a couple of amps from the battery for a few seconds to remove any surface charge which might be present. This
test, while only returning rudimentary results, is quick and simple. Do not be fooled by the overly simplified battery model taught in college physics. The simple physics model contains merely an ideal voltage source and resistor. The oxidation-reduction chemical reaction of the lead-acid battery contains parasitics which defy the imagination. Corporations have invested considerable resources into modeling it and only recently have had moderate success.
When measuring charge by means of specific gravity, keep in mind that the volume of fluid in a cell affects the reading. While the solute in a given cell is constant, water leaving the cell through outgasing causes the specific gravity reading to increase even though no additional energy was driven into the cell. Therefore, make these measurements only after filling the cell to a reference level so that your measurements will be repeatable and therefore more accurately indicate the state of charge. When adding water to a cell, however, make sure the electrolyte is mixed well before taking the measurement. Mixing is most easily accomplished (if the battery is nearly fully charged) by charging the battery a few minutes driving it to outgas slightly.
Deciding what level to consistently fill battery electrolyte to involves some trade-offs. The highest level you should fill a cell to is its ring. On the other hand, the electrolyte level must never be so low as to expose the plates. This causes immediate and permanent loss of capacity. Anything in between will work just fine. When the level is kept low, the battery is better able to fend off a freeze of bitter cold when it is only moderately charged. The trade-off is that a low level requires increased visual checking to see that the level is not too low. When the level is kept high, the danger of freezing (when only moderately charged) is more likely but the battery will be much more tolerant of outgassing its water (it forgives you for not watching it closely).
Generally any water that is safe to drink is safe to use to refill a battery cell. It is important, however, that mineral content (iron) be minimized. The iron will react with the acid resulting in neutralization which permanently lowers its capacity. The safest practice is to use distilled water.
The following table illustrates typical specific gravity values for a golf cart or marine cell in different stages of charge:
100% Charged 1.255 - 1.260
75% Charged 1.220 - 1.225
50% Charged 1.185 - 1.190
25% Charged 1.150 - 1.155
0% Charged 1.115 - 1.120
It is important to correct for temperature in a specific gravity measurement. Subtract or add 0.004 points for each degree difference from 80oF. For example, a reading of 1.220 taken at 10oF would have a corrected reading of 1.192 (1.220-0.004(80-10)=1.192). Many hydrometers have color zone coding (green, white, and red) suggesting good, moderate, and dead gravity ranges. These ranges are only applicable for automotive batteries.
In the winter make sure a battery charge never goes below maybe 50%. The electrolyte of a fully discharged battery will freeze at a mere +32oF while a fully charged battery is good to less than thirty degrees below zero.
An indicator that a battery is nearing 100% charge is when it begins to outgas. During the charging process, sulfate ions combine with hydrogen in the water to form sulfuric acid and lead dioxide. Oxygen (O2) and hydrogen (H2) begin to evolve from the solution when the process nears completion and can be easily observed as bubbles sparkling at the surface. When a cell cap is removed, the bubbling action is violent enough to spew minute amounts of electrolyte out of the cell falling on the surface of the battery. Outgassing can be detrimental to the longevity of a battery if a high rate of charge is continued. A rule of thumb to observe is to charge at 20% to 25% of battery capacity where outgassing is not occurring and less than 5% once it begins. As an example, a 100 Ah battery could be charged at 20-25 amps while highly discharged and then less than 5 amps once outgassing begins. A note of caution should be given here in that these gasses are explosive. Always make sure reasonable ventilation is provided during the charging of lead-acid batteries.
Install a battery array in such a way as to facilitate ease of maintenance. Make sure there is enough room above the batteries to allow a hydrometer access. The space above the batteries should allow you to visually inspect fluid levels. There should be no wires obstructing battery extraction. If access to the batteries is awkward, you will tend to examine them less often. The times that you do examine them will be more difficult.
Keep a container of baking soda handy to neutralize battery acid spills. The baking soda will double as an electrode cleaning agent. However, make sure you wash the electrodes thoroughly with ordinary tap water after cleaning.
Keep cotton rags handy around a battery installation to wipe dirt and dust from the surface of the batteries when doing routine maintenance. Such contaminants can contribute to self discharge.
There is a myth that placing lead-acid batteries directly on a concrete floor for extended periods will discharge the batteries. However, there is a glimmer of truth in this tale. A non-beneficial temperature inversion layer may form within the battery if placed on a cold surface such as an outdoor concrete slab during warm weather. It is, therefore, a good practice to stand off batteries from a concrete floor with wood.
Low temperatures severely limit the capacity of a battery but this should not be confused with a loss of energy. Drawing energy from a very cold battery causes an internal temperature increase restoring a proportionate amount of its capacity. On the other side of the spectrum, if a battery is operated at an ambient in excess of 100oF its self discharge rate increases and overall battery longevity is shortened. The optimum temperature for battery operation is 80oF.
Many years ago there were television commercials giving battery usage tips. One of the tips supposedly would help a battery crank a car’s engine in sub-zero temperatures. Viewers were told to first turn on headlamps for a moment before cranking the engine. The reason given was that this would heat the battery and that the battery would then be able to deliver more energy. Hopefully the reader is knowledgeable enough at this point to see the fallacy in such a practice. Yes, drawing maybe 20 amps to drive headlamps will heat the battery a little but wait a minute. The operator is preparing to draw in excess of 300 amps to drive the electric starting motor. Maybe the battery will be hampered at first by a low internal temperature but why chemically lower the battery capacity first. What comes first: the tail or the dog?
A number of factors influence the efficiency of a lead-acid battery. Under optimum conditions a battery will usually operate at about 80% efficiency. One of the primary factors affecting efficiency is the discharge rate. Driving a battery to 50% charge in a single hour will dramatically lower its efficiency for that cycle. The same battery, however, once properly recharged and driven to 50% charge over ten hours will deliver significantly increased energy than it did in the earlier condition.
Either raise or lower the temperature from 80oF and the efficiency decreases further.
Lead-Acid battery manufacturers today only spec amp-hour (Ah) ratings for golf cart batteries. All other batteries have a variety of specifications but it is virtually impossible to otherwise find Ah specs for them. It is possible, however, to extract a rudimentary Ah spec from the specification called "reserve capacity" given in minutes. Reserve capacity is a test in which a 25 amp load is placed on a battery at 80oF. The time is then measured that it takes the battery voltage to reach 10.5 volts. For example, a battery having a reserve capacity of 120 minutes would equate to 50 Ah [120min x 25a / 60 (min/hr) ]. Convert reserve minutes to Ah by multiplying by the ratio 25/60. Reserve capacity should only be considered rudimentary or worst case since it tends to measure battery capacity under stressful conditions which reduces efficiency. The same battery, if discharged at the smaller rate of 5 amps, would yield an increased net capacity.
One last tip: If you are going to own and work with lead-acid batteries, you have the perfect excuse to tell your wife you are getting out that old leisure suit you haven’t worn in twenty years. Polyester is quite resistant to battery acid spills. If, however, you are just going to continue wearing those comfortable blue jeans and warm cotton shirts, you might as well take up smoking again. From time to time unnoticed drops of battery acid will end up on your fine clothing creating the same holes your cigarettes used to make. If smoking is out of the question maybe you should consider learning to weld. Better yet, wear protective clothing and eye glasses.
About the author: The author has been an electrical engineer for twenty years having earned his degree from Cal Poly, San Luis Obispo. At The Boeing Company he participated in the evaluation of experimental ballistic reentry vehicles, and designed power conversion systems. At the Johns Hopkins University Applied Physics Laboratory he was involved in the development of fleet systems weapons and submarine stealth for the US Department of the Navy. For the last seven years he has worked in southeastern Michigan’s automotive industry.
THE UNABRIDGED SECOND AMENDMENT
by J. Neil Schulman
If you wanted to know all about the Big Bang, you'd ring up Carl Sagan, right ? And if you wanted to know about desert warfare, the man to call would be Norman Schwarzkopf, no question about it. But who would you call if you wanted the top expert on American usage, to tell you the meaning of the Second Amendment to the United States Constitution ? That was the question Iasked A.C. Brocki, editorial coordinator of the Los Angeles Unified School
District and formerly senior editor at Houghton Mifflin Publishers -- who himself had been recommended to me as the foremost expert on English usage in the Los Angeles school system. Mr. Brocki told me to get in touch with Roy Copperud, a retired professor of journalism at the University of Southern California and the author of "American Usage and Style: The Consensus." A little research lent support to Brocki's opinion of Professor Copperud's expertise. Roy Copperud was a newspaper writer on major dailies for over three decades before embarking on a a distinguished 17-year career teaching journalism at USC. Since 1952, Copperud has been writing a column dealing with the professional aspects of journalism for "Editor and Publisher", a weekly magazine focusing on the journalism field.
He's on the usage panel of the American Heritage Dictionary, and Merriam Webster's Usage Dictionary frequently cites him as an expert. Copperud's fifth book on usage, "American Usage and Style: The Consensus," has been in continuous print from Van Nostrand Reinhold since 1981, and is the winner of the Association of American Publisher's Humanities Award. That sounds like an expert to me. After a brief telephone call to Professor Copperud in which I introduced myself but did not give him any indication of why I was interested, I sent the following letter: "I am writing you to ask you for your professional opinion as an expert in English usage, to analyze the text of the Second Amendment to the United States Constitution, and extract the intent from the text.
"The text of the Second Amendment is, 'A well-regulated Militia, being necessary for the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.'" The debate over this amendment has been whether the first part of the sentence, 'A well-regulated Militia, being necessary to the security of a free State', is a restrictive clause or a subordinate clause, with respect to the independent clause containing the subject of the sentence, 'the right of the people to keep and bear Arms, shall not be infringed.' "I would request that your analysis of this sentence not take into consideration issues of political impact or public policy, but be restricted entirely to a linguistic analysis of its meaning and intent. Further, since your professional analysis will likely become part of litigation regarding the consequences of the Second Amendment, I ask that whatever analysis
You make be a professional opinion that you would be willing to stand behind with your reputation, and even be willing to testify under oath to support, if necessary." My letter framed several questions about the test of the Second Amendment, then concluded: "I realize that I am asking you to take on a major responsibility and task with this letter. I am doing so because, as a citizen, I believe it is vitally important to extract the actual meaning of the Second Amendment.
While I ask that your analysis not be affected by the political importance of its results, I ask that you do this because of that importance." After several more letters and phone calls, in which we discussed terms for his doing such an analysis, but in which we never discussed either of our opinions regarding the Second Amendment, gun control, or any other political subject, Professor Copperud sent me the follow analysis (into which I have inserted my questions for the sake
Of clarity):
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[Copperud:] "The words 'A well regulated militia, being necessary to the security of a free state,' contrary to the interpretation cited in your letter of July 26, 1991, constitutes a present participle, rather than a clause. It is used as an adjective, modifying 'militia,' which is followed by the main clause of the sentence (subject 'the right', verb 'shall').
The to keep and bear arms is asserted as an essential for maintaining a militia. "In reply to your numbered questions:
[Schulman:] "(1) Can the sentence be interpreted to grant the right to keep and bear arms solely to 'a well-regulated militia'?"
[Copperud:] "(1) The sentence does not restrict the right to keep and bear arms, nor does it state or imply possession of the right elsewhere or by others than the people; it simply makes a positive statement with respect to a right of the people."
[Schulman:] "(2) Is 'the right of the people to keep and bear arms' granted by the words of the Second Amendment, or does the Second Amendment assume a preexisting right of the people to keep and bear arms, and merely state that such right 'shall not be infringed'?"
[Copperud:] "(2) The right is not granted by the amendment; its existence is assumed. The thrust of the sentence is that the right shall be preserved inviolate for the sake of ensuring a militia."
[Schulman:] "(3) Is the right of the people to keep and bear arms conditioned upon whether or not a well regulated militia, is, in fact necessary to the security of a free State, and if that condition is not existing, is the statement 'the right of the people to keep and bear Arms, shall not be infringed' null and void?"
[Copperud:] "(3) No such condition is expressed or implied. The right to keep and bear arms is not said by the amendment to depend on the existence of a militia. No condition is stated or implied as to the relation of the right to keep and bear arms and to the necessity of a well-regulated militia as a requisite to the security of a free state. The right to keep and bear arms is deemed unconditional by the entire sentence."
[Schulman:] "(4) Does the clause 'A well-regulated Militia, being necessary to the security of a free State,' grant a right to the government to place conditions on the 'right of the people to keep and bear arms,' or is such right deemed unconditional by the meaning of the entire sentence?"
[Copperud:] "(4) The right is assumed to exist and to be unconditional, as previously stated. It is invoked here specifically for the sake of the militia."
[Schulman:] "(5) Which of the following does the phrase 'well-regulated militia' mean: 'well-equipped', 'well-organized,' 'well-drilled,' 'well-educated,' or 'subject to regulations of a superior authority'?"
[Copperud:] "(5) The phrase means 'subject to regulations of a superior authority;' this accords with the desire of the writers for civilian control over the military."
[Schulman:] "(6) (If at all possible, I would ask you to take account the changed meanings of words, or usage, since that sentence was written 200 years ago, but not take into account historical interpretations of the intents of the authors, unless those issues can be clearly separated."
Copperud:] "(6) To the best of my knowledge, there has been no change in the meaning of words or in usage that would affect the meaning of the amendment. If it were written today, it might be put: "Since a well-regulated militia is necessary tot he security of a free state, the right of the people to keep and bear arms shall not be abridged.'
[Schulman:] "As a 'scientific control' on this analysis, I would also appreciate it if you could compare your analysis of the text of the Second Amendment to the following sentence, "A well-schooled electorate, being necessary to the security of a free State, the right of the people to keep and read Books, shall not be infringed.' "My questions for the usage analysis of this sentence would be, "(1) Is the grammatical structure and usage of this sentence and the way the word modify each other, identical to the Second Amendment's sentence?; and "(2) Could this sentence be interpreted to restrict 'the right of the people to keep and read Books' _only_ to 'a well-educated electorate' -- for example, registered voters with a high-school diploma?"
[Copperud:] "(1) Your 'scientific control' sentence precisely parallels the amendment in grammatical structure. "(2) There is nothing in your sentence that either indicates or implies the possibility of a restricted interpretation." Professor Copperud had only one additional comment, which he placed in his cover letter: "With well-known human curiosity, I made some speculative efforts to decide how the material might be used, but was unable to reach any conclusion."
So now we have been told by one of the top experts on American usage what many knew all along: the Constitution of the United States unconditionally protects the people's right to keep and bear arms, forbidding all governments formed under the Constitution from abridging that right. As I write this, the attempted coup against constitutional government in the Soviet Union has failed, apparently because the will of the people in that part of the world to be free from capricious tyranny is stronger than the old guard's desire to maintain a monopoly on dictatorial power.
And here in the United States, elected lawmakers, judges, and appointed officials who are pledged to defend the Constitution of the United States ignore, marginalize, or prevaricate about the Second Amendment routinely. American citizens are put in American prisons for carrying arms, owning arms of forbidden sorts, or failing to satisfy bureaucratic requirements regarding the owning and carrying of firearms -- all of which is an abridgement of the unconditional right of the people to keep and bear arms, guaranteed by the Constitution. And even the American Civil Liberties Union (ACLU), staunch defender of the rest of the Bill of Rights, stands by and does nothing. it seems it is up to those who believe in the right to keep and bear arms to preserve that right. no one else will. No one else can. Will we beg our elected representatives not to take away our rights, and continue regarding them as representing us if they do? Will we continue obeying judges who decide that the Second Amendment doesn't mean what it says it means but means whatever they say it means in their Orwellian doublespeak ?
Or will be simply keep and bear the arms of our choice, as the Constitution of the United States promises us we can, and pledge that we will defend that promise with our lives, our fortuned, and our sacred honor ? (C) 1991 by The New Gun Week and Second Amendment Foundation. Informational reproduction of the entire article is hereby authorized provided the author, The New Gun Week and Second Amendment Foundation are credited. All other rights
reserved.
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About the Author
J. Neil Schulman is the award-winning author of novels endorsed by Anthony Burgess and Nobel-economist Milton Friedman, and writer of the CBS "Twilight Zone" episode in which a time-traveling historian prevents the JFK
assassination. He's also the founder and president of SoftServ Publishing, the first publishing company to distribute "paperless books" via personal computers and modems. Most recently, Schulman has founded the Committee to Enforce the Second Amendment (CESA), through which he intends to see
the individual's right to keep and bear arms recognized as a constitutional protection equal to those afforded in the First, Fourth, Fifth, Ninth and Fourteenth amendments. J. Neil Schulman may be reached through: The SoftServ Paperless Bookstore, 24-hour bbs: 213-827-3160 (up to 9600 baud).
Mail address:
J. Neil Schulman
PO Box 94, Long
Beach, CA 90801-0094.
GEnie address: SOFTSERV
softserv@genie.geis.com
http://www.shadeslanding.com/firearms/unabridged.2nd.html
Seventy-Six
By
William Cullen Bryant
What heroes from the woodland sprung,
When through the fresh awakened land,
The thrilling cry of freedom rung,
And to the work of warfare strung
The yeoman's iron hand!
Hills flung the cry to the hills around,
And ocean mart replied to mart,
And streams, whose springs were yet unfound,
Pealed far away the startling sound
Into the forest's heart.
Then marched the brave from rocky steep,
From mountain river swift and cold;
The borders of the stormy deep,
The vales where gathered waters sleep
Sent up the strong and bold.
As if the very earth again
Grew quick with God's creating breath,
And from the sods of grove and glen,
Rose ranks of lion-hearted men
To battle to the death.
The wife whose babe first smiled that day
The fair fond bride of yestereve,
The aged sire and matron grey,
Saw the loved warriors haste away,
And deemed it sin to grieve.
Already had the strife began'
Already blood on Concord's plan,
Along the springing grass had run
And blood had flowed at Lexington
Like brooks of April rain.
That death-stain on the vernal sward,
Hallowed to freedom all the shore;
In fragments fell the yoke abhorred--
The footstep of a foreign land
Profaned the soil no more.
Death to the New World Order!