What About the A BatteryThe Importance of Balance in Trickle Charging Those Misleading"Statements About A Battery Elimination" Comparing the Methodsof Charging and Their Costs The Best Rate and When to ChargeBy EDGAR H. FELIXfails to function because of a APower is a term used to describeWith charging rates as high as two amperesgradually until the set at last comparatively few who manufacture such a device supplying B current also most simplicity and, by observingdischargeddevices which enable aSOCKETreceiving set to draw battery. In this case, unless the trickle charger available, the danger of grave overcharge,its power directly from the electric light has a high charging adjustment which permits resulting in quick destruction of the battery, ismains. To the uninformed enthusiast, it usually bringing back the battery from its discharged constantly present. On the other hand, a fewimplies a complete elimination of all the elements state to full charge quickly, it is difficult to restore hours a week with a high charging rate, and a lowof the power supply system which require care it to good working order without the assistance of trickle charge for the balance of the time, willand attention.a high-rate charger. When a user experiences a keep the battery in the best of condition.Socket power devices now on the market fall run-down A battery, he naturally increases the There are always occasions when a set is used aslightly short of accomplishing this desirable trickle charging rate to the maximum, which great deal for a few days for special reasons, andresult. They do, however, reduce to the very should bring the battery back to full efficiency in this case a higher charging rate istemporarilyminimum the care and attention required to in several days. But often, he considers such an necessary to bring the battery back to full charge.keep the receiver's power supply at full efficiency.experience as evidence that the charging rate The table on page 27 shows the chargingThe storage battery and rectifier, which should permanently be kept at maximum. For adjustments recommended by Philco. This tablethese devices invariably combine in a single a long time, perhaps even two or three months, gives the average number of hours a dayunit, do nevertheless require a little intelligent this rate gives satisfaction because the battery is a set may be used at various current drains andcare, and, given that care, are both reliable and always kept fully charged, but, sooner or later, the charging rates. For example, with a five-tube setconvenient.battery breaks down completely from prolonged used 3.02 hours a day, each tube drawing aThe most advanced types of socket power and continued overcharging, Active material quarter of an ampere, the trickle charger at theequipment comprise a charging device and storagestarts to fall out of the plates and, also, the speci-0.2 ampere adjustment will keep the battery upbattery so designed that the battery is left fic gravity of the electrolyte may rise to a high to full charge. If the set is used but two hours aon charge at a slow or trickle rate during the value and the distilled water of the solution day, the trickle charger should be shut off byentire time the set is not in use. Therefore the requires renewal every few days. Usually the removing the attachment plug occasionally sostorage battery is either discharging through the manufacturer is condemned for these misfortunes, that constant overcharging is avoided.tubes of the receiver or being charged by the while the cause issimply incorrect setting of the On the other hand, such a five-tube receivertrickle charger. Theoretically, the only attention trickle charging rate.may be used for twelve hours within two dayswhich must be given such socket power devices Different socket power devices use different because of some special broadcasting event,is the occasional addition of distilled water to combinations of charging rate. Philco, for example,and this would draw a total of fifteen amperethe storage battery and the trickle charger.has three adjustments, low, medium, and hours from the battery. For example, the setEven when turning on and off the set, it is not high, giving 0.2, 0.33, and o.6-ampere charging may be in use from eight o'clock until one a. m.necessary to think about the trickle charger connectionsrates respectively. Willard uses a low and a high on one evening and from six o'clock to one a. m.because, by the use of an automatic adjustment, giving 0.5 and 2.0 amperes, while on the next, drawing a total of fifteen amperedevice, the receiver's "on-off" switch disconnectsGould offers no less than five adjustments, 0.2 hours from the storage battery. Between thesethe charger when the switch is turned on, to 0.25 ampere, 0.275 to 0.320 ampere, o 350 to two periods of listening, and between the secondand connects it when in the "off" position. 0.425 ampere, 0.450 to 0.750 ampere, and 0.9 to period and a third period which we shall supposeWith most devices provision is also made for 1.5 amperes, according to line voltage.commences at eight o'clock on the thirdconnecting the power line to a Bevening, the battery is rechargedsupply device when the controlfor thirty-six hours at the lowswitch is in the "on" position.rate, which gives it back 7.2A minimum of attention is indeedampere hours. Now, if the cur-attained, provided that therent drain, after this experiencetrickle chargeis of the correctof twelve hours' use in two days,rate to offset the current drawnis continued at its normalwhen the set is used. But, alas,average for about three hoursthis condition of perfect balancedaily, and the normal chargingof input to output is not alwaysrate of 0.2 ampereis maintained,happily secured. Therefore thethe battery may never be restoredfilament current require mentsto full charge.of the receiver and the number ofUnderstanding these conditions,hours a dayit is used must beit is not difficult to under-determined fairly accurately, andstand the correct charging rate.the charging rate by the trickleEstimate the average needs ofcharger adjusted to meet them.your set in ampere drain andFor this reason, A power combinationshours of use and adjust the trickleare equipped with meanscharging rate recommended byof adjusting the trickle chargethe manufacturer for that load. Ifrate to suit the power requirementsyou depart from this average useof different receivingby extended use on special oc-sets.casions, use a higher chargingThe importance of balancingrate for a few days to counterbalanceit. On the other hand,charge and discharge becomesapparent when we consider theif the receiver is subject to longeffects of undercharge and overchargeRADIO BROADCAST Photograph periods of disuse, disconnect theupon the life and con-attachment plug for a few daysdition of the storage battery.A THREE-IN-ONE SOCKET POWER DEVICEwhen you estimate the batteryIf the trickle charge rate is tooCombining trickle charger, storage battery, and B power supply in one unit. Althoughmany manufacturers combining the first two in one unit, there These are operations of theto be in a fully charged condition.low, the battery voltage will fallut-
MAY, <strong>1927</strong> WHAT ABOUT THE A BATTERY? 27them, you getthe true convenience of socketpower.The only other attention required to keep asocket power device in working order is to keep itconstantly filled with fresh distilled water. TheGould "Unipower" has an ingenious method ofreminding you of this water matter because therectifier cell is so designed that the rectifier cutsoff just before the storage battery needs renewalof water. Hence the battery will go dead beforeits plates have been unduly exposed because oflack of water. Philco supplies a convenient hydrometerwith certain of its larger storage batteries,fastened in the top of the cell case. If the wateris at the proper level, squeezing the hydrometerbulb draws electrolyte into the charge indicator.If it fails to do so, you are plainly warned that thewater must be renewed. Philco and others alsouse built-in charge indicators which permit one tosee the electrolyte level through the glass wallsof the cell, simple markings indicating the dangerpoint.MISLEADING STATEMENTSWE HAVE observed the advertising andliterature of several concerns purportingto describe A-battery eliminators or insinuatingthat their devices eliminate A-battery troubles,storage battery attention, etc. A number of thesedevices which we have examined, are simply storagebatteries with trickle chargers. To imply"elimination of storage battery troubles" withsuch devices is plain deception. If manufacturersare not above using such deception in theiradvertising, dealers can hardly be blamed forextending this misrepresentation to the consumer.Readers are therefore warned to examine socalledA-battery eliminators carefully beforepurchase, lest they prove to be only the conventionaltrickle charger-storage battery combination.They then require the simple attentionsherein recommended and will fail in service ifthey are not given it.The condition of a storage battery, whetherused in connection with a trickle charging deviceor otherwise, is not difficult to check so long asit receives fairly normal treatment. Voltmeterreadings, however, should not be relied uponunless a very accurate, high-grade instrument isused.A hydrometerisvery useful for the purpose,because it isinexpensive and somewhat moreaccurate in its indications than a voltmeter.However, it too is subject to certain slightdiscrepancies which, when understood, are notdifficult to account for.When a battery is fully charged, the specificgravity is at its maximum. Constantovercharge produces boiling,reducing the water in the solutionand accordingly increasing the specificgravity. Extended and continuedovercharging (such as thatresulting from an excessive tricklecharging rate) tends to force thesulphuric acid to the top of the cellso that we sometimes get a highspecific gravity reading althoughthe battery goes mysteriously deadafter a few minutes of use.Another misleading state is manifestwhen an unusually strong sulphuricacid solution is used. Thissubterfuge is sometimes employedto make a storage battery appearbetter than it really is. In automobileservice, where extremely heavycurrent is drawn for a few seconds,it is of advantage to use a strongsolution because an electric startersometimes draws as much or morethan ninety amperes from the battery but, with aradio battery, no such heavy loads are drawn.The only advantage gained by the use of a strongsolution is a little higher terminal voltage andbetter specific gravity reading; on the otherhand, it causes more rapid deterioration of theplates. The specific gravity reading for a radiostorage battery at full charge should be between1225 and 1300, depending upon the recommendationsof the maker. The majority of radioTo110V. iov. JA.C, .C. _
- Page 1 and 2: RADIO BROADCASTVOLUME XIMAY, 1927,
- Page 3 and 4: INDEX.ContinuedPAGEThreshold of Hea
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- Page 11 and 12: MAY, 1927WITH MACMILLAN TO THE ARCT
- Page 13: THE MARCHInterpretation of Current
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- Page 18 and 19: The ElectricalA Non-Technical Expla
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- Page 22 and 23: A Balanced Short-Wave ReceiverA Des
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- Page 34 and 35: AS THE BROADCASTER SEES ITDrawings
- Page 36 and 37: 38 RADIO BROADCAST MAY, 1927Interes
- Page 38 and 39: Some Facts About Coil DesignThe Osc
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