Charging System TS

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Charging System Tests

by Richard Atwell(c) Copyright 2005-2011

Contents:

1. Battery Tests

2. Battery Chargig

!. Battery "oad Testig

#. A word abo$t %pti&a

5. Ter&ials

'. ow does the Alterator wor

*. Alterator %$tp$t

+. ow the ,oltage Reg$lator ors

. Testig the ,oltage Reg$lator

10.Testig the Alterator

11.Alterator ear

/$ite ote whe yo$r battery stops chargigyo$ are let woderig why s$bse$etatte&pts at co&poet replace&et ail toc$re the proble&. 34e pro4ided a set odetailed steps to ollow to help yo$ deter&iewhich parts ha4e ailed. teps are &ay b$tthoro$gh to help to h$t dow yo$r electrical

gre&lis.

This article oly co4ers b$s alterators adot the early style geerators.

Beore we start6 there are two co4etios to obser4e. 7irst6 , wirig syste&s areegati4e gro$d which &eas that the egati4e post o the battery is coected to the4ehicle body. This &ay see& at$ral b$t positi4e gro$d syste&s e8ists (lie 4itageBritish &ade 9ag$ars) which ca be co$sig to people who ha4e wored o theopposite syste&.

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ecod6 whe talig abo$t c$rret6 i the a$to&oti4e ield we &ore ote &eaco4etioal c$rret which states that c$rret lows ro& positi4e to egati4e. reality6electros (which are the charge carriers) low ro& egati4e to positi4e b$t theco4etioal syste& is ill$strated i &ore te8ts (a hold o4er ro& the early days osciece).

Overview:

The chargig syste& is &ade $p o !co&poets: (A) the battery6 (C) alteratorad (C3) 4oltage reg$lator. The battery isthe heart o the syste& that prod$ces4oltage ad pro4ides storage or electricalc$rret. he the egie is o6 the battery

powers the lights ad accessories. heyo$ are tryig to start the egie6 thebattery powers the starter ad igitiosyste&. t also eergi;es the alteratorwhich begis to prod$ce its ow c$rretwhe the alterator ears the egie3s idlespeed.

The alterator charges the battery whilethe egie is r$ig< witho$t it6 thebattery wo$ld r$ dow 4ery $icly.

Altho$gh the alterator is a so$rce oc$rret6 yo$ &ight thi that oce yo$ startthe egie yo$ co$ld discoect thebattery b$t the syste& is ot desiged tooperate that way. =o$ sho$ld ot r$ the egie witho$t the batterycoected especially i yo$ ha4e 7 or sesiti4e electroics that always e8pect 12-1#,.The battery is itegral to the proper $ctioig o the electrical syste&.

he the egie is r$ig6 the battery ad alterator pro4ide power si&$ltaeo$sly.The alterator tries to power the electrical syste& ad charge the battery at the sa&eti&e b$t beca$se the alterator3s o$tp$t is so&ewhat depedet o the egie rp&6

whe loads are high the battery ca istatly s$pply &ore c$rret whe ecessary. t3sthe electrical >shoc absorber> i the syste& which is essetial a h$ge capacitor(&eas$red i 7 ot $7?). he the alterator is spiig at high rp& it is easilyprod$cig eo$gh electricity to &eet all o the c$rret re$ire&ets.

ow ad whe to charge the battery is deter&ied by the 4oltage reg$lator whichcotrols the c$rret low ro& the alterator to the battery. t3s &o$ted o the irewall

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which acts as a gro$d ad heat si. The ,R reads the battery 4oltage ad 4aries thealterator3s o$tp$t accordigly.

Beca$se the battery6 alterator ad ,R are so closely co$pled6 ig$rig o$t which oe isat a$lt ca be diic$lt witho$t ollowig the proper diagostic steps. The diagra& o the

right shows the tight electrical co$plig betwee co&poets. @eerally battery testsare si&ple b$t deter&iig whether the alterator or ,R is at a$lt ca be co&plicated$less yo$ $derstad how they wor.

the wirig sche&atic yo$ ca see how the alterator is idirectly coected to thebattery 4ia the starter soleoid. =o$ ca also see how the igitio switch is batterypowered ad acti4ates the warig la&p which ser4es a d$al p$rpose: it co&pletes acirc$it that also eergi;es the alterator 4ia the 4oltage reg$lator e4e beore the egiehas bee started. hat3s i&portat to ote ro& the begiig is that there are a lot oelectrical cotacts i4ol4ed. Prit o$t this diagra& ad eep it i yo$r glo4eco&part&et.

Beca$se the battery is the easiest to test ad the &ost essetial6 we3ll ig$re o$t how totest it irst. The we3ll proceed to the 4oltage reg$lator ad the alterator last. Alog theway 3ll e8plai how each wors so the reaso or each tests ca be $derstood.

Battery Tests:

Disclaimer:lectricity ad battery acid ca both be 4ery dagero$s. lectrical shortsca start ires. he hadlig batteries6 $se all preca$tios beca$se the cotets are a

highly corrosi4e potetially e8plosi4e poiso. se 4etilatio6 re&o4e ewelry6 wearprotecti4e clothig ad eyewear6 etc.

The stoc si;e battery or the b$s is a @ro$p #2 or @ro$p #1 as rated by the BatteryCo$cil teratioal (BC). These are $ropea style batteries: they loo the sa&e b$tthe ter&ials are re4ersed co&pared to a >A&erica> battery. 7or $rope6 positi4e iso the right ad egati4e o the let with the ter&ials acig towards yo$. yo$p$rchase aother gro$p battery or yo$r b$s6 the cables &ight ot reach i yo$ lip itaro$d so the ter&ials ace the body6 especially o a *!-* b$s. Dote that the '+-*2&odels ha4e the battery cables re4ersed (gro$d strap is behid the taillight) so yo$co$ld $se a battery.

As yo$ ca see6 o the two batteries the di&esios are 4ery si&ilar with the @ro$p #1beig abo$t 2> loger.

Group CCA CA Ah RC Size (inches

#2 #50 5'5 5# *' &i -5E+ 8 * 8 '-!E#

#1 '50 +15 '! 110 &i 11-1E2 8 '-*E+ 8 '-5E+

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o what do the ratigs &eaF

Cold Craig A&ps (CCA) - ow &ay a&ps that ca be deli4ered or !0 sec at07 (-1*C) beore the 4oltage drops below *.2,. That is the &ii&$& 4oltagere$ired to egage &ost starters ad soleoids.

Craig A&ps (CA) - ow &ay a&ps that ca be deli4ered i the sa&esceario b$t or !0s at !27 (;ero C).

A&p o$rs (Ah) - ow &$ch c$rret a $lly charged battery ca s$pply or 20ho$rs beore the 4oltage drops below 10.5, at +07 (2*C). 7or e8a&ple6 !Adeli4ered or 20 ho$rs wo$ld $stiy a '0Ah ratig. hile dri4ig6 a !A load isbelow the typical c$rret draw which is why batteries r$ dow so easily.

Reser4e Capacity (RC) - This is the ti&e i &i$tes that the b$s ca be dri4ewith the headlights o ater the alterator ails. This test ass$&es a 25A load at

+07 (2*C) ad is the legth o ti&e it taes or the 4oltage to drop to 10.5,. Asyo$ ca see the gro$p #2 is goig to last abo$t a ho$r i yo$r alterator ails atight where as the slightly large gro$p #1 will last 50G loger.

The r$le o th$&b with regard to battery selectio is to a4or CCA i cold cli&ates adRC i war&er cli&ates whe co&pariso shoppig. Always apply the &ii&$& BCgro$p ratigs i yo$r selectio process beore yo$ elect to choose aother battery gro$pthat its the battery cla&p so yo$ do3t ed $p picig a $derpowered battery.

ere3s a list o typical drai le4els or a $el iected egie to gi4e yo$ a idea o thec$rret de&ads:

Con!ition Amperage

gitio o !.5A

H parig lights !.+A

H low bea&s (55) 15.5A

H high bea&s ('0) 1*.2A

gie o 5.0A

H low bea&s (55) 1*.2A

H high bea&s ('0) 1+.+AH alterator -5.0A

As yo$ ca see the a&o$t o r$ig ti&e yo$3ll ha4e at ight will be slightly logertha the RC ratig o yo$ battery beca$se the load is less tha 25A speciied by thestadard. yo$ are r$ig yo$r stereo as well6 =II,. The last etry i the table is the&ost iterestig as it shows the alterator powerig all o the electrical loads (&i$s thelights) while chargig the battery at the sa&e ti&e.

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Beyod si;e6 there are two basic types o batteries that are costr$cted dieretly:starter ad deep cycle. A deep cycle battery ca be discharged al&ost co&pletely adrecharged o4er ad o4er b$t oly with &oderately low c$rret draw. A starter batterycaot be deep discharged. hy ot $se a deep cycle all the ti&erF Beca$se it3s otdeiged to deli4er high c$rret loads or short periods o ti&e to r$ the starter. 7ail$re

to $se each battery type as iteded will shorte its liespa.

Test 1. Coir& the battery 4oltage

Alterators are desiged to eep a battery charged ad power the accessories i theb$s. They are ot desiged to recharge a dead battery so yo$ &$st test the batterybeore yo$ atte&pt to diagose the rest o the chargig syste&. Alterators see& liethey are worig 100G o the ti&e b$t i act$ality they are t$rig oEo at reg$lariter4als. Atte&ptig to recharge a dead battery will o4erwor the alterator ad &ayb$r it o$t.

A$to&oti4e electrical syste&s are ot e8actly 12,. The lead-acid battery cosists o 'cells coected together i series. ach cell prod$ces appro8 2.1, ro& ro& theelectroche&ical reactio so the battery 4oltage is really closer to 12.'-12.+, whe $llycharged. =o$ eed a 4olt&eter to &eas$re the battery.

Beca$se we are so $sed to hearig abo$t 12, a$to&oti4e electrical syste&s6 we tedto igore the e8act battery 4oltage. Tae or e8a&ple a battery that reads 12.!5,. At irstit see&s to be i perect coditio (abo$t 12, rightF) b$t i reality a 12.!5, battery is

oly 50G charged6 12.0, is 25G ad 11.+0, is co&pletely draied. hee4er thebattery reads 11., or lower it is basically a >dead> battery that has lost al&ost all o itscharge. This will gi4e yo$ a ro$gh g$ide to the state o charge (%C).

hat are the critical 4oltages or operatioF

1. *-, to egage the starter

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2. 10.5, to ire the $el iectors o (*5-* &odels)

!. igitio syste&: 4aries accordig to spar pl$g gap

Below those &ii&$&s yo$ will be st$c tryig to start the egie.

he batteries go bad6 the plates iside s$lphate ad iterere with the or&alche&ical reactio. $latio is a ter& that reers to the battery che&istry. ach cell6cotais positi4e lead plates that are coated with lead ad egati4e plates that arecoated with lead dio8ide. he the battery is coected to a load that ca$ses c$rret tolow6 the hydroge ad s$lphate ios i the electrolyte co&bie with the plates to or&lead s$lphate which or& as crystals. As the electrolyte beco&es de4oid o ios6 itbeco&es weaer ad the ability to pass c$rret lesses. he the battery is recharged(c$rret re4ersed) the lead s$lphate ret$rs to sol$tio lea4ig lead behid o oe platead lead dio8ide o the other.

To say a battery has s$lated &eas that the lead s$lphate caot ret$r to sol$tio.This is beca$se the bod betwee the s$lphate ad the plate re$ires &ore electricity tobrea tha ca be geerated thr$ or&al chargig. i&ply lea4ig a battery o the shelor a &oth will ca$se a light le4el o s$latio that ca be re4ersed by rechargig. Theloger the battery si;e that &ore layers o crystals b$ild $p ad e4et$ally the batterydies. The c$re is to recharge batteries reg$larly whether o the shel or i $se.

t3s also possible or 4ibratio ad deep dischargig to ca$se the lead plates to shedtheir coatig ad e4et$ally short o$t the cell. ice the battery electrical che&istry isbased o s$race area6 it beco&es weaer i the sa&e way that a low electrolyte le4elca$se the battery to $derperor& (low 4oltage ad low c$rret capacity). heddig also

occ$rs ro& age.

"ow electrolyte le4els ad s$latio ro& deep dischargig are reported to acco$t oro4er 50G o battery ail$res yet they are easy to pre4et. Reg$lar chec-$ps o thebattery ca easily e8teded their lie to $ll.

%te a battery that appears good caot pro4ide eo$gh c$rret to start the egie.Beore taig ay readigs6 with the egie o6 t$r o the headlights or 15 &i$tes tore&o4e ay s$race charge ro& the battery the t$r the lights o ad tae yo$r&eas$re&ets.

%ce yo$ t$r o the egie ad the alterator ics i6 the battery 4oltage will rise ear1#,. The higher 4oltage is ecessary to charge the battery (p$sh the electros agaistthe battery 4oltage). Iore o the alterator later so a4oid t$rig the egie o at thispoit.

Che&ical reactios are te&perat$re depedet so yo$r e8act &eas$re&et will 4aryro& &ie e4e i yo$ ha4e the sa&e brad o battery:

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Con!ition Battery "oltage

itial chec 12.*0,

Jey i 12.50,

"ights o 12.21,

15 &i later 12.12,

"ights o 12.#1,

aother 5 &i later 12.'0,

Be s$re to test the 4oltage at the battery posts ad ot at the cla&ps beca$se there&aybe corrosio that will aect the tr$e readig.

Ater this test6 &y tr$e battery readig shows that it3s dow 0.10, (12.*-12.',) or 0Gcharged. A battery with a higher le4el o s$race charge wo$ld show a &$ch lower ial4al$e ater the headlights had p$t the battery $der load so yo$ ca see why testig the

iitial 4oltage is3t s$iciet.

A see&igly good battery whe tested or 4oltage ca e8hibit a large 4oltage drop $derload. Jeep the probes o the ter&ials or 10-15s to otice ay coti$al 4oltage drops.The 4oltage sho$ld hold airly steady o a good battery while the lights are o b$t wo$ld0.01, drop e4ery 1-2s o a wea battery. Ater 15&i i the battery 4oltage is i the .88rage ad still droppig yo$ ca be s$re that it is ti&e to replace the battery beca$se itcaot deli4er power or electrical loads ay&ore.

A battery lie this will ote sprig bac to a 12.88 4oltage ater yo$ t$r the lights owhich de&ostrates the i&portace o taig &$ltiple 4oltage readigs ad watchig

the res$lts while the lights are still o.

t is &$ch easier to otice these decre&etal 4oltage drops o a digital &eter co&paredto a aalog oe.

yo$ ca3t ig$re o$t why yo$r battery is r$ig dow whe yo$r let yo$ b$s sit yo$&ay ha4e a c$rret drai iss$e. The actory cloc ad draws oly a ew &A ad i yo$ha4e a stereo it &ight draw so&e c$rret to eep it settigs. These accessories arecalled parasitic loads ad they will e4et$ally drai yo$r battery dow to the poit that itcaot start yo$r egie. Coect yo$r a&&eter betwee the battery egati4e cablead post to test or e8cessi4e loads. K% D%T start the egie or t$r o the headlights

or yo$ will blow yo$r a&&eter. %ly a id$cti4e cla&p sho$ld be $sed to &eas$rethose large a&o$ts o c$rret while the egie is startigEr$ig. Ko ot coect yo$ra&&eter i yo$ are ot 100G s$re that the c$rret draw is less tha the c$rret ratig oyo$r a&&eter i yo$ are ot $sig a c$rret cla&p ad istead &eas$rig it directly.

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Ayti&e the c$rret draw is greater tha !5&A yo$ sho$ld s$spect a accessory orwirig proble&. The best way to atte&pt to isolate the iss$e is to p$ll $ses oe ad ati&e ad watch yo$r a&&eter to see where the largest drop i c$rret occ$rs. 7ro&there yo$ ca e8a&ie the wirig diagra& or that part o the wirig haress to try adpipoit the proble&.

Test 2. Chec the electrolyte le4el

A lead acid battery is so a&ed beca$se it cosists o lead plates ad a s$l$ric acidsol$tio. The sol$tio is '#G distilled water ad !'G s$lph$ric acid (2%#). yo$ getthis sol$tio o yo$r clothig it will eat thro$gh it so always be care$l aro$d a ope

battery. =o$ do ot wat it gettig i yo$r eyes either.

yo$ ha4e a sealed battery it will ote ha4e a idicator o the top that idicates thebattery state o charge alog with a leged to read it. t3s $s$ally a colored idicator thatshows good6 wea ad dead. ort$ately they oly test oe o the si8 cells so their$se$less is li&ited.

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Iay batteries are ot sealed ad yo$ ha4e to chec o the electrolyte le4el by poppigthe sealig caps. o&e sealed batteries will let yo$ ope the& b$t oly atte&pt this ithere are caps o top. Atte&ptig to crac ope aother id o sealed battery isco$ter prod$cti4e. reco&&ed selectig a o-sealed battery i war& cli&ate. Theywill &ore easily allow yo$ to add distilled water that teds to e4aporateEboil away i hot

weather ad will e8ted the lie or yo$r battery.

=o$ ca peer ito the iller opeigs to chec the l$id. Iore ote that ot theelectrolyte le4el is too low ro& the heat ha4ig e4aporated the water iside the battery.Beca$se the battery has large plates iside ay portio o the plates ot co4ered byelectrolyte6 will ot participate i the electrical reactio. other words less c$rret willbe prod$ced.

The iller caps are desiged to let hydroge gasses escape ad allow the acid &ist tocodese ad drop bac ito the battery. Jeep the area aro$d these caps clea addo ot allow ay cota&iats to all ito the battery.

%ly ill $p the battery with distilled water ro& the grocery store. %te yo$ ca b$y agallo or L1 or so. Iae a ote o how low each cell is ad do ot o4erill. Po$r i $steo$gh to co4er the tops o the plates iside. yo$ o4erill the&6 they &ae lea o yo$i the battery boils o4er ro& beig o4ercharged.

o&eti&es a battery low o water will per&aetly da&age itsel. =o$ &ay be able toill6 recharge ad ret$r the battery to or&al b$t yo$ will id that it slowly dischargesad strads yo$ withi 2-! &oths. he that happes yo$ eed to p$rchase a ewbattery.

Test !. Test the electrolyte

The state o the electrolyte is &eas$red $sig a hydro&eter which &eas$res thespeciic gra4ity o sol$tio. =o$ isert the hydro&eter ito the cell6 s$ee;e the b$lb tos$c $p the electrolyte ad tae the readig at the eye le4el o the l$id. =o$ the ret$rthe electrolyte to the cell ad repeat the process or the other cells. t3s 4ery i&portat toeep the hydro&eter clea otherwise yo$ will cota&iate the electrolyte ad the&ieral deposits will iterere with battery cell operatio.

"oo or a tester that has $&bers. The oes with colored balls or a loatig strip arehard to read the e8act speciic gra4ity.

peciic gra4ity (@) is a ter& ro& che&istry that idicates the weight o a sol$tiorelati4e to water which is gi4e the 4al$e o 1.000. $l$ric acid has a @ o 1.+!5 adso a $lly charged battery has a @ o 1.2*0. As the battery discharges6 the s$lphateios i the sol$tio co&bie with the lead plates ad the sol$tio beco&es weaer. By&eas$rig the sol$tio we ca ig$re o$t how &$ch charge the battery has let.

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=o$ &ay woder yo$ ca3t &$ltiplyEadd 1.+!5 (!5G acid) H 1.000 ('#G water) to get1.2*0F t is beca$se a) the acid sol$tio already had so&e water cotet ad b) those

$&ber are based o a stadard te&perat$re which is &$ch lower tha the a&biette&perat$re that yo$ are taig yo$r &eas$re&ets at.

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Test chart:

#ercentage charge Speci$ic Gravity at %&' "oltage

100G 1.2'5 12.'*

*5G 1.225 12.#*50G 1.10 12.2'

25G 1.155 12.0+

0 1.120 11.1

the dierece betwee the higher ad lowest 4al$e ro& all si8 cells is greater tha0.050 yo$ also ha4e a bad battery. o&eti&es a cell ails co&pletely ad at$rallyres$lts i a s$bstatial total 4oltage drop (either 0, or ay readig below 11,) so agaiit3s ti&e to replace that battery.

o&e hydro&eters are te&perat$re co&pesatig< others are ot ad calibrated at +07. yo$rs is ot a$to co&pesatig6 the yo$ &$st add 0.00# to yo$r res$lt or e4ery 107abo4e +07 ad s$btract 0.00# or e4ery 107 below +07. "$cily this 4ariatio is s&alleo$gh that yo$ ca largely igore it $less yo$ are peror&ig yo$r tests atte&perat$re e8tre&es.

Be s$re yo$r battery is sec$red properly: 4ibratio has bee ow to ca$se the& to ailpre&at$rely.

Battery Charging:

yo$34e deter&ied yo$r battery is dead ad is too wea to start the egie6 yo$34e gotto charge it. @ettig a $&p ro& aother 4ehicle is a optio. ere3s how to do it saely:

1. Iae s$re the dead battery is3t ro;e

2. Jeep cars is$lated ro& each other

!. Coect H4e $&per cable ro& good battery to dead battery

#. Coect the -4e $&per cable ro& the good battery to the egie bloc or agood gro$d away ro& the dead battery to a4oid spars.

5. tart the booster car (with the good battery)

'. R$ the booster car or 10 &i$tes at 2000 rp& to i4igorate the dead batteryad war& the electrolyte

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*. tart the b$s with the dead battery

+. T$r o the headlights ad a o the b$s with the dead battery

. Re&o4e -4e $&per cable ro& good battery6 the dead battery

10.Repeat abo4e with H4e (this will pre4et a accidetal short with the cable)

=o$r ,R wo3t be able to tell yo$34e got a good or bad battery while coected to theother booster car. %ce yo$ discoect6 r$ yo$r egie at speed or !0 &i$tes or soad will yo$ be able to deter&ie i yo$r battery is chargig properly by t$rig it o adatte&ptig to restart. Ko ot do this i yo$ are ar ro& ho&e? he yo$ ially t$r othe egie6 yo$ sho$ld chec the 4oltages ad @ agai to coir& i the battery hasbee partially restored to health.

A $se$l de4ice to ow is a battery charger. These are great or eepig shel batteries

charged beca$se they slowly drai dow o their ow. These ie8pesi4e &odels area$to&atic6 co&e i a$to ad &otorcycle si;es. yo$ $se the &otorcycle $its to chargea car battery they will tae a log ti&e b$t still wor eecti4ely (good to ow i yo$ha4e both types o 4ehicles beca$se the a4erage a$to charger will o4er-charge a&otorcycle battery).

The &a$al type chargers are ti&er based ad deli4er a higher c$rret &ore $icly.These $its are $s$ally 4ery b$ly (they ha4e wheels?) ad ote e8pesi4e. yo$ do3t$derstad the &a$act$rer3s spec o yo$r battery yo$ &ay da&age it by s$pplyigtoo &$ch c$rret.

Re&e&ber to always discoect the gro$d cable i yo$ are goig to charge the batteryi the b$s to a4oid 4oltage spies ad li&it the 4oltage that is see by accessoriesbeca$se the chargers operate abo4e 1#, d$rig so&e o their chargig phases.

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Battery oa! Testing:

hile 4olt&eters ad hydro&eters are good diagostic tools6 oce yo$ deter&ie thatyo$r battery is at least *5G charged6 it3s sae to load test witho$t $rther chargig. Ayo these tests are s$itable:

T$r o high bea&s or 5 &i$tes.

Kisable the igitio ad $el p$&pEiectors ad cra the egie or 15 secs.

K$rig the test the 4oltage sho$ld ot drop below .',. yo$ wait 5 &i$tes ater thetest the battery sho$ld regai it3s 50G charge 4oltage le4el. either o these tests ail6yo$ sho$ld replace the battery.

yo$ still are3t s$re i yo$r battery is bad ater testig ad atte&ptig to recharge6 yo$ca ha4e it load tested at the local a$to parts store. They will ote $se a carbo pile

based load tester that si&$lates a large c$rret lie a starter wo$ld draw. The battery$s$ally eeds to ha4e at least a *5G charge beore the test ad the tester is $s$ally setto !8 the a&p-ho$r ratig o the battery or 1E2 the CCA ratig.

The tester will ha4e a ga$ge that shows goodEbad ad $s$ally a readig o .', orhigher d$rig the load test idicates a good battery. The test lasts 10-15 secod &a8. the battery is ot at roo& te&perat$re6 the c$t-o or the threshold 4oltage sho$ldicreaseEdecrease 0.1, per 107 chage o electrolyte te&perat$re.

Iost o these load testers are D%T co&patible with the ewer A@I style batteries lie%pti&a. A@I stads or Absorbed @lass Iatte ad the electrolyte is s$speded i a gel

so the battery does3t lea. =o$ &ay per&aetly da&age this type o battery tryig totest it at the a$to parts store.

Iidtroics is a co&pay that &aes a ew id o battery tester that is startig toappear at a$to parts stores. t is co&pact ad easy to $se altho$gh it has 4aryigreports o acc$racy. They sell &ay &odels b$t &ost oly pro4ide passEail ior&atio.This tester &eas$res the cod$ctace o the battery istead o si&$latig a real loadlie the carbo pile testers. The cod$ctace (i4erse o resistace) chages as thes$race coditio o the plates iside chage. All batteries ha4e so&e iteralresistace iside ad the &icroprocessor iside the tester p$t the battery thro$gh aseries o tests beore rederig a decisio. Beca$se its res$lts are table loo$p based6 i

it ass or the CCA o the battery ad yo$ ca3t id it o the battery label yo$ wo3t beable to test it ad deped o the res$lts.

o&e o these testers do ot test the ewer A@I style batteries lie %pti&a ad so&edo. Iae s$re yo$ ow the re$ire&ets beore b$yig oe o these cod$ctacetesters. Persoally6 do3t thi they are worth the cost.

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A wor! a)out Optima:

%pti&a is battery $lie yo$34e e4e see beore. t3s &ade by 9ohso Cotrols (oethe largest battery &a$act$rers) ad is the closest yet to a leaproo desig. yo$ aretired o leas r$stig o$t yo$r battery tray6 yo$ eed a %pti&a. They cost &ore tha a

or&al battery b$t they also last loger beca$se they do3t lose water log beoreyo$34e oticed with a reg$lar battery. They ca also deli4er a h$ge a&o$t o startigc$rret co&pared to a or&al battery beca$se they ha4e a 4ery low iteral resistaceo ! &illioh&s.

The %pti&a !#R is the &odel that its o$r b$sses (pict$red below). !# is the BC gro$p$&ber ad R &eas the ter&ials are re4ersed ($ropea layo$t).

Optima CCA CA Ah RC Size (inches

!#R 1000 +00 50 110 &i 10 8 ' *E+> 8 * 1'E1'>

Accordig to %pti&a6 whe $lly charged the 4oltage sho$ld be 12.+, ad the battery isco&patible with ay chargig syste& that o$tp$ts 1!.!-15.0,. he the battery is deadit reads 10.5,.

Terminals:

As the battery ter&ials corrode6 the electrical resistace that b$ilds $p is eo$gh toi&pede both the chargig ad startig syste&. A s&all 0.1 oh& resistace at the battery

ter&ials ca red$ce the starter3s o$tp$t by 2G beca$se o the eor&o$s c$rretdraw. The power to the headlights is also red$ced by !2G which red$ces the 4is$alitesity by &ore tha 50G. hy does this happeF %h&s law: whe the c$rret le4elis high6 the 4oltage drop is proportioally high. 7or e8a&ple6 0.1 oh& ad 10A M 1,drop.

A &aority o charig ad startig diic$lties ca be traced to the wirig i the or& ocorrosio or da&age to ter&ial or so&eti&es it3s as si&ple as loose coectio. itherway6 yo$ are bo$d to e8periece this o a 25-!0 year old 4ehicle lie a baywidowb$s.

Test 1. Chec or resistace

The copper eds o the cables corrode as do the lead ter&ials ad the battery posts.tart by &eas$rig the resistace betwee the ter&ial ad the battery posts ad theeach ed o the cable.

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both cases the 4oltage yo$ wat to see 0.0, 4olts with the battery coected or 0.1oh&s or less resistace with the gro$d cable discoected. T$r o the headlightswhe testig the 4oltage beca$se a load o the battery will &ae 4oltage drops easierto witess. Ko ot t$r o the headlights whe testig the resistace. %ly testresistace with the battery gro$d cable discoected.

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he &eas$rig resistace yo$ wat to irst deter&ie what readig yo$ get by si&plyto$chig the probes together. ires ad iteral co&poets that are part o yo$r &eterha4e resistace that yo$ ha4e to acco$t or i yo$r &eas$re&ets. yo$ &eas$re 0.2oh&s ad yo$r probes acco$t or 0.1 oh&s yo$ are really &eas$rig 0.1 oh&s.

additio to the braided cable coectig the battery egati4e to the body yo$ &$stalso chec the tras&issio gro$d strap that coects the starter (4ia it3s casig) to thebody. A large eo$gh 4oltage drop there will also ca$se startig diic$lties (&ore abo$tthis below).

Test 2. Clea the ter&ials

ea4y corrosio ca be e$trali;ed ad cleaed with a wire br$sh ad a sol$tio obaig soda ad water. pecial ter&ial cleaers are sold that ca clea the posts (let)ad the cables (right).

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he ter&ials are clea ad dry6 reattach the cables ad coat the ter&ials withpetrole$& elly or a special p$rpose battery ter&ial spray.

the corrosio is e8tesi4e yo$ &ay ha4e to replace the cable or cri&pEsolder o a ewter&ial. "ead based ter&ials sho$ld be a4oided beca$se they do3t hold their shapead corrode badly. preer the high $ality co&poets $sed below. They do3t corrodead pro4ide a soldered &oist$re proo coectio ro& the cable to the ter&ials.

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o&e people isist that yo$ replace the etire cable b$t that depeds o the coditioo the cable ad i they sell cables? A si&ple ter&ial replace&et lie this ca brigyo$r electrical syste& bac to lie ad pre4et the $ecessary p$rchase o a ewstarter or alterator.

Test !. Chec the starter ter&ials

=o$ also wat to clea the large ter&ial o the starter soleoid. 7or so&e reaso ,chose ot to p$t a r$bber boot o4er these ite&s. Ay other electrical coectio i the$dercarriage that is protected by a boot is $s$ally i great shape ater 25-!0 years. Dotso with the soleoid. The large ter&ial where the battery (blac) ad alterator (grey)

cables &eet is ter&ial !0.

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Ignore my remove starter comment in the photo: I reused it from another article.

additio6 yo$ eed to &ae s$re yo$34e got good coti$ity betwee betwee all thestarter ter&ials beca$se i yo$ ca3t start yo$ ca3t charge either. 7ollowig the circ$it6cleaig ad testig:

Battery H4e to starter (ter&ial !0).

tarter (ter&ial 50) to starter (ter&ial !0) 4ia igitio switch

tarter soleoid to starter body (short gro$d strap)

tarter Body to tras&issio (4irt$ally g$arateed good).

Tras&issio gro$d strap to 4ehicle ra&e.

Battery gro$d strap to battery -4e ter&ial.

"astly6 the battery case itsel sho$ld be clea beca$se 4oltage ca lea ro& thepositi4e ter&ial to the battery body to gro$d thro$gh the d$st ad acid that collects otop. se a &ild baig soda sol$tio ad co&pletely dry the battery beore istallig it.

*ow !oes the Alternator wor+:

Beore e8plai how to test the 4oltage reg$lator ad alterator eed to e8plai howboth wor. yo$ are a&iliar with its operatio yo$ &ay wat to sip the e8t ! sectios.

The alterator charges the battery by re4ersig the c$rret low thro$gh it ad re4ersigthe che&ical reactio iside as a res$lt. t also s$pplies c$rret to the etire electrical

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syste&. 7$lly testig the alterator re$ires a $derstadig o how it operates adwhe it geerates 4oltage ad c$rret.

The alterator is a electric geerator with rectiied o$tp$t. This &eas that $lie KCgeerators it prod$ces AC ad t$rs it ito KC istead o prod$cig KC directly. This

has pro4e to be a &ore eiciet desig tha geerators beca$se:

&ore c$rret ca be prod$ced at low rp&s

4oltage ca be &ore acc$rately cotrolled with solid state reg$lators

they eed less &aiteace

they cost less to &a$act$re

yo$ let yo$r old beetle idle6 the battery teds to r$ dow &ore easily with a

geerator. =o$ &ay also otice the chargig light o the dash at idle or whe dri4ig atight ti&e. This is beca$se the geerator by desig has to be dri4e at a lower &a8.speed tha a alterator which ca easily be dri4e at 28 egie speed. i8 4oltelectrical syste&s were e4e worse: the headlight o$tp$t wo$ld icrease as yo$ re44edthe egie beca$se the geerator was so poor ad pro4idig c$rret to eep the batterycharged at idle.

A alterator cosist o a &o4ig coil o wire called the rotor ad a statioary coil o wirecalled the stator. Both coils are wrapped aro$d &agets to icrease their respecti4eelectrical stregths.

KC c$rret is s$pplied to the rotor by the 4oltage reg$lator ad this geerates a c$rreti the stator. A slip rig o the rotor is i coti$o$s cotact with a pair o br$shes as itspis which coect the rotor to the 4oltage reg$lator. This is $lie the &echaicalswitchig that occ$rs i the co&&$tator o a geerator which is li&itig. The costatcotact is possible beca$se the solid state power diodes i the rectiier circ$it o thealterator pro4ide the c$rret polarity switchig $ctio. This also &eas that o o$tp$tc$rret passes thro$gh the br$shes to wear the& o$t pre&at$rely.

To &ae the alterator &ore eiciet6 three sets o wires &ae $p the stator adbeca$se o the way they are wrapped6 4oltage is prod$ced i ! separate phases &$chlie tras&issio i city power lies. The power diodes rectiy the !-phase AC ito a KC-

lie wa4eor& with 4ery little ripple. This is preerred by batteries as they charge as wellas electroics yo$ &ay be operatig. The re$ecy o the AC is deri4ed ro& the speedo the rotor which is go4ered by the egie speed.

The shape o the rotor is a claw-pole desig cosistig o a &agetic iro shell thateeps the wirig iside ro& lyig o$t (e8plodig) at high rp&s. t is a precisio&achied part with a shat that r$s i two roller bearigs. C$rret lows thro$gh thewidigs o the rotor ad the e8act a&o$t lowig deter&ies how &$ch c$rret is

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id$ced i thestator ollowigthe laws o

electro&agetis&. Precisely &eterig the o$tp$t c$rret is the ob o the 4oltagereg$lator which &oitors the battery 4oltage to deter&ie its load ad state o charge.

Alternator Output:

%te ot well ow is that alterators do ot prod$ce 4oltageEc$rret as soo as theystart to spi. There is a ;ero-a&pere speed at which the alterator reaches its rated4oltage beore it ca geerate ay c$rret. This is typically 1000 rp& (500 egie rp&). ca&e $p which the secod ig$re beca$se the alterator p$lley o the b$s is hal the

si;e o the egie a p$lley ad so the alterator spis at twice the egie speed. De8ti the series o i&portat e4ets d$rig alterator spi $p is the idlig speed: typically at1500 rp& (*50 egie rp&) the alterator &$st be able to satisy the eeds or logter& cos$&ers (basic electrical de&ads) witho$t r$ig dow the battery.

9$st abo4e the idle speed is the c$t-i speed at which the alterator begis to deli4erc$rret or the irst ti&e. The e8act speed depeds o the battery 4oltage6 4oltage ro&the alterator warig light (pre-e8citatio power)6 the rate o chage o rotatioal-speed

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ad the &agetic re&aece o the rotor3s &agets. yo$34e started yo$r egie ad>heard> the alterator slow dow the egie at the begiig o ast idle war&-$p this isthe c$t-i speed heard i actio.

There is also a speed ratig or the &a8i&$& c$rret o$tp$t6 typically '000 rp& (!000

egie rp&) ad there is a &a8i&$& rp& at which the alterator ca spi which isdictated by the roller bearigs ad carbo br$shes iside as well as the a beca$se ittae power to p$ll air thro$gh. % a4erage this li&it is 206000 rp& (106000 egie rp&):&$ch higher tha ay stoc , egie ca reach ad ay that do are drag racers whoha4e o eed or a alterator (s$bstit$te a dry cell battery or &ageto powered igitiosyste&).

7ially6 the alterator ca3t r$ all day log at 100G d$ty cycle (+0G is &orereasoable) so yo$ sho$ld actor yo$r c$rret load re$ire&ets with that i &id.

*ow the "oltage Regulator ,or+s:

The 4oltage reg$lator cotrols the ield c$rret i the rotor o the alterator. t &eas$resthe 4oltage o the battery (decreasig) ad by chagig the c$rret (icreasig) i therotor6 &ore 4oltageEc$rret (icreasig) is prod$ced i the stator o the alterator whichis $sed to charge the battery. This i4erse relatioship betwee the 4oltage reg$latorad the alterator is all that3s re$ired to eep the battery charged ad the electricalsyste& powered &ost o the ti&e.

The earliest 4oltage reg$lators istalled o baywidows were &echaical relay based

de4ices b$t they ha4e bee replaced by loger lastig &ore acc$rate solid state4ersios. Both styles are coig$red to prod$ce 1#, ro& the alterator ad o &ore6hece their a&esae. The &echaical 4ersios are the easiest to $derstad so 3llsip the details o the &icrocotroller ad DPD power trasistor wirig i the solid state4ersio.

the alterator were r$ at idle speed o a bech yo$ co$ld &eas$re the o$tp$tc$rretE4oltage by chagig the ip$t c$rret. The slip rig path thro$gh the rotor has ai8ed resistace so accordig to oh&s law ( M ,ER) yo$ ca icrease the c$rret to therotor si&ply by 4aryig the 4oltage. This is the basis or how the 4oltage reg$latorcotrols the alterator3s o$tp$t.

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the diagra& the let i&age shows the basic wirig layo$t ad the ! diagra&s o the

right show how c$rret lows i the ! stages o operatio. =ellow arrows idicate s&allc$rret low while orage arrows idicate a larger c$rret low. The 4oltage reg$latortaes a ! wire ip$t which is $ses to sese the alterator 4oltage ad cotrol it:

1. rotor egati4e K- (brow)

2. rotor ield K7 (gree)

!. stator o$tp$t KH (red)

C - Alterator

C3 - ,oltage Reg$lator

T1a - wirig coector to warig la&p

The bl$e wire leads to the warig la&p i the istr$&et pael ad the red wire at BHleads to the battery (4ia the starter soleoid). sig the leged i the wirig diagra&sectio o Betley3s electrical chapter6 yo$ ca lear to read the ,R iteral wirigsche&atic: iside is a relay cotrollig two cotacts ad a ew resistors. The blac blocto the let o C represets the rotor iside the alterator.

The ,R operates i ! stages. The irst stage (ey o) iitiates whe the igitio ey ist$red to the o positio b$t beore the egie is started (alterator o). Power ro& theigitio switch lows thro$gh the warig la&p ad thro$gh the rotor ield widig iorder to e8cite the alterator.

stage 2 (alterator o) the egie has started6 the alterator spis $p at 28 egiespeed ad ear the alterator3s ;ero-a&pere speed (aro$d 500 egie rp&)6 it begisto prod$ce 4oltage at BH thro$gh oe set o diodes which is ed to the battery ad alsoto KH which is piced $p at the 4oltage reg$lator. The 4oltage at KH ollows BH b$t4aries slightly beca$se KH recei4es its sigal ro& the stator thro$gh a separate set odiodes.

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ith si&ilar 4oltage at both eds o the warig la&p ow6 it goes o$t. t3s alsoiterestig to ote that the ;ero-a&pere speed is largely deter&ied by the power ratigo the warig la&p. o$r case6 it3s a or&al 1.2 istr$&et light b$lb.

The 4oltage at KH is ed to K7 by the ,R ad the icreasig &agetic ield i the rotor

id$ces a alteratig c$rret i the stator which is rectiied ito KC ad ed to thebattery 4ia BH. The o$tp$t 4oltage 4aries accordig to the ip$t 4oltage (ed bac itothe rotor by the ,R) ad the egie rp&.

the !rd stage (alterator idle) the o$tp$t 4oltage has reached the 1#, set poit atwhich ti&e the relay (coil) iside the reg$lator eergi;es ad breas the cotact isidewhich coects KH ad K7 ad sh$ts K7 to gro$d 4ia K-. hile the &aority oc$rret lows to gro$d6 a s&all c$rret is ed thro$gh the rotor so the alterator is3tco&pletely t$red o. The diodes iside the alterator protect it ro& the battery at allti&es d$rig these switchig operatios.

As the 4oltage drops at BH6 the relaycotacts re-ope ad the ,R cycles tostage 2 ad the process begis all o4eragai. The 4oltage is cotrolled $sig a4ariable re$ecy d$ty cycle approach.This syste& is pretty brailess ad slow torespod. t3s hoped that a) ay s$ddechages are absorbed by the battery b) a10, >dead> battery wo3t be preset toorce the alterator to r$ 100G d$ty cycletryig to charge it. These are two reasosthat solid state reg$lators are so &$chbetter: the better oes are &icrocotroller based ad $derstad a lot &ore abo$t thestate o the electrical syste& tha a si&ple relay. =o$ $st ha4e to &ae s$re yo$ i4esti oe ro& Bosch (0 12 0'2 00*) pict$red right ad ot a piece o $ ro& A$to;oe.The latter cotais a $derpowered switchig trasistor ad oly abo$t L1 worth oelectroic parts iside.

olid state ,Rs ca also e8ert &$ch ier cotrol o4er the rotor3s ield 4oltage. At lowrp&s the ield 4oltage ca be set high to help the alterator eep the battery chargedbeca$se it3s less eiciet at low rp&s. 4ery alterator has a spec that describes ac$r4e o c$rret o$tp$t 4s. egie speed which ted to rise sharply aro$d the idlespeed ad the le4el o.

At higher rp&s6 the alterator o$tp$t is s$iciet that oly a low 4oltage is re$ired.he the battery 4oltage is low (high c$rret drai) the rotor 4oltage is icreased toicrease the o$tp$t. All this happes istataeo$sly as the solid state ,R &oitors thebattery ad alterator as the electrical load ad rp&s chage. ow does it acco&plish

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this cotrolF By sesig the phase o the o$tp$t 4oltage it ca deter&ie the rotorspeed. As a side ote6 e4e tho$gh the alterator o$tp$t is rectiied ro& AC to KC6so&e o the AC leas thro$gh the diodes ad appears as a KC ripple.

he the reg$lator ails6 the battery is either a) i dager o beig o4ercharged or b)

ails to charge. he the 4oltage le4el is too high &ost batteries will gi4e o gas as thes$lph$ric acid ad water i the electrolyte deco&poses ito hydroge ad o8yge.Re&e&ber the ideb$rgF =o$ do3t ot wat ay spars to occ$r whe this ishappeig which is why the $&p startig tips reco&&ed that yo$ coect the egati4e

$&per cable to a good egie gro$d away ro& the battery egati4e post.

Testing the "oltage Regulator:

Dow we ow how the syste& wors6 we ca easily diagose it. Always chec the

reg$lator beore the alterator beca$se they ail &ore ote.

Test 1. dicator "a&p

the la&p is ot co&ig o whe yo$ t$r the ey to o yo$ eed to 4eriy that the b$lbis good. the battery is coected the the b$lb sho$ld be gettig battery 4oltage. hatis ote &is$derstood is the bac o the istr$&et cl$ster is ot &ade ro& a siglepiece o &etal. Iost o it is gro$ded to the body by the circle o spaded coectors othe bac b$t the area where the idicatorEwarig lights reside is is$lated by plastic6so&eti&es i two separate sectios. =o$3ll see a tab o that is$lated sectio to pro4ide12, $st or those lights istead o the $s$al gro$d.

ice it3s oly a b$lb it ca b$r o$t lie ay other istr$&et la&p. To chage the b$lbyo$ do3t eed to re&o4e the istr$&et cl$ster b$t wo$ld ad4ise yo$ to discoectthe battery beore yo$ accidetally short o$t the istr$&et pael ad s&oe theistr$&et wirig haress or start a ire.

Test 2. ,eriy 4oltage at haress pl$g

To test the reg$lator yo$ eed a 4olt&eter ad a set o probes that ca reach ito the$derside o the coector to to$ch the ter&ials. do the right-side &o$tig screwad the let the ,R rotate 0 C so yo$ ca &ore easily access the $derside o the

coector.

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State

D-(re!.)lue

D'(green

D/()rown

amp

gitio o6 egie o 0, 0, 0, o

gitio o6 egie o 1.2+, 0.'#, 0, ogitio o6 egie idle 1#, 5, 0, o

gie o (ast idle) 1#, 5, 0, o

Dote: All 4oltages are KC. yo$ try to &eas$re the AC 4oltage at K7 with the egier$ig yo$ sho$ld see oly a ew &,. The K7 4oltage with the egie o depeds othe act$al battery 4oltage. =o$ will see N5, o a $lly charged battery ad $p to 12, asthe %C o the battery decreases. he the egie is o it will also deped o thebattery 4oltage (%C H electrical load) ad the readig will be less tha 1,.

t taes 4ery little ti&e or the egie to spi the alterator ast eo$gh to geerate $llo$tp$t 4oltage. yo$ ha4e to re4 the egie to get the warig light to go o$t yo$ willprobably coir& a alterator proble& by &eas$rig a battery le4el 4oltage at KH withthe ey o ad the egie o. A readig o 1-2, readig at both KH ad K7 ater theegie starts idicates a diode proble& i the alterator.

Ieas$re the battery 4oltage with the egie r$ig. t sho$ld be 1!.+-1#.2 e4e withthe lights o. The e8act 4oltage depeds o yo$r alterator ad wirig resistaces b$tit3s ot $co&&o to see a 0.#-0.+, drop with the lights o. =o$3ll id that the&echaical 4oltage reg$lators ha4e tro$ble eepig the 4oltage right at 1#, whe thesyste& is $der load.

the ,R see&s to be chargig the battery correctly the a $ll-ield test o the alteratorsho$ld be peror&ed.

Test !. Test the reg$lator

yo$r 4oltage reg$lator is &echaical yo$ sho$ld eel it clicig. yo$ ca3t eel itabo4e the egie 4ibratio6 yo$3ll eed to ope it $p. By looig at the photo yo$ &ight

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woder6 did Bosch really $st seal it $p with tape. =es? To re&o4e the cap6 si&ply c$t thetape i the &iddle all the way aro$d witha $tility ie ad care$lly wiggle the topo.

side is a ield coil (soleoid)6 a choead a pair o cotacts that rese&ble a seto Bosch igitio poits. The coil iscoected across KH ad K-. he theigitio is o6 battery 4oltage at KH co&esro& the igitio switch ad lows thro$ghthe poits to the rotor. This is the iitiale8citatio that the alterator re$ires.he the alterator starts prod$cig the1#, set poit 4oltage6 the coil eergi;es6breas the cotacts ad the ield c$rret

goes al&ost to ;ero. The choe e8ists toli&it the arcig thro$gh the poits.

the &echaical reg$lator has3t b$red o$t yo$ sho$ld see these readigs whe&eas$rig resistace betwee ter&ials:

KH ad K7 - 0.! oh&s

K- a K7 - ope

K- ad KH - +0 oh&s

yo$ ha4e the later style ,R with a real power trasistor &o$ted o the botto& (solidstate)6 the yo$r readigs will be 4ery dieret so do3t worry.

% the botto& is a ther&al resistor that drops i resistace as the itae te&perat$redecreases. The p$rpose is the alter the chargig set poit beca$se batteries ca becharged to higher 4oltages i the cold. i&ilarly whe they get too hot6 the set poit islowered i order to eep the& ro& boilig o4er.

t3s ot possible to test the ther&istor witho$t switchig the cotacts iside beca$se thec$rret ro& yo$r oh& &eter taes the path o least resistace which is betwee KH ad

K7. =o$ ha4e to ope the reg$lator ad toggle the switch by had. Tae the ther&istorreadig betwee KH ad K7. t sho$ld read abo$t 2.! oh&s at '+7 ad decrease withte&perat$re (a $ic blast o cold spray will coir&).

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the reg$lator checs o$t6 the yo$ eedto peror& a $ll-ield test o the alteratorto r$le the ,R o$t co&pletely. Thisi4ol4es6 discoectig the pl$g ro& the,R ad coectig the battery positi4e 4ia

patch cable (preerably at the BH ter&ialo the alterator) to the K7 (gree wire)ter&ial o the pl$g. Dow r$ the egieor a ew secods< $st log eo$gh to4eriy 4oltage at the battery. This sho$ldoly be doe or a istat beca$se the4oltage co&ig o$t o the alterator will be$reg$lated b$t it will deter&ie i the ,Reeds to be replaced or i the alterator isat a$lt. Beca$se we34e bypassed the ,R6 sesiti4e electroics &aybe at ris? yo$regie is $el iected reco&&ed that yo$ tae the alterator to a alterator repair

shop or a $ll ield bech test istead (tests are $s$ally ree).

Koes it get hotF o&eti&es it ca. The ,R taes 12, ro& the battery as ip$t. iteeds to pass 2A o c$rret thro$gh the #.5 oh& rotor to raise the o$tp$t 4oltage to 12,that &eas it has to sed , thro$gh. This &eas it has to absorb !, at 2A o c$rretwhich e$ates to ' o power that it has to dissipate as heat.

Test #. Test the wirig haress

This is3t a easy step with the alterator istalled b$t it is possible. =o$ eed todiscoect the haress pl$g ro& the alterator to test the resistace o each wire.

Resistace sho$ld be 0.1 oh&s or less. Corrosio is $s$ally hea4ier o the alteratorside b$t yo$ sho$ld also e8a&ie the 4oltage reg$lator pl$g icl$dig the wirig thatleads to the idicator light o the dash. se a pic ad bed the tabs iside ro& therot to re&o4e the $is$lated ter&ials ro& the rear. Badly corroded ter&ials ca bereplaced easily beca$se this haress teds to ha4e a lot o slac i it.

the wire is bad6 yo$3ll ha4e to replace the wirig ad shri wrap it. reco&&ed $sigthe sa&e colors ad be s$re ot to get the colors &i8ed $p whe yo$ reattach theter&ials to the pl$gs or yo$3ll s&oe the alterator.

Testing the Alternator:

Test 1. Physical idicators

s the belt tightF it3s too tight it will place a side load o the bearigs ad pre&at$relywear the& o$t. it3s too loose6 it &ay slip o the p$lley ad ot spi the alterator asteo$gh. 8cessi4e slippig oises are always ob4io$s b$t ot always preset. The belt

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stretches ad re$ires re-ad$st&et6 especially ater yo$ istall a ew oe. 34e e4esee belt stretch ro& the egie al&ost o4erheatig i e8tre&ely hotEdry weather.

ice the rotor is &agetic yo$ ca test that it is gettig c$rret witho$t disasse&blig it(the ,R has to be worig with the ey o or this test):

gie o - o &agetis& betwee p$lley $t ad screwdri4er.

gie o - attractio &eas &agetic ield is preset so br$shes ad rotor are&aig good cotact.

Be s$re to test that the screwdri4er has o resid$al &agetic p$ll beore yo$ test itagaist the alterator. there is little or o p$ll o the screwdri4er6 $pl$g the ,R adshort the red ad gree wires together. Dow t$r o the ey ad this will pro4ide therotor with a direct 12, ield which sho$ld icrease the &agetic p$ll.

there is still o p$ll6 test the 4oltage o the red wire. there is o 4oltage the haress&aybe broe or ot &aig proper cotact. there is still o &agetis& the thealterator &aybe bad (diode6 short6 etc).

Test 2. 7$ll ield test

This was described abo4e i the ,Rsectio. The alterator sho$ld prod$ce0G o its rated o$tp$t d$rig the test to

be cosidered good. the photo yo$ casee the techicia at the reb$ild shop $st$ses a large electric &otor to spi $p thealterator. They all see& to ha4e this ido ho&e &ade set$p ad $s$ally ha4eso&e hard to read oscilloscope.

Jeep i &id that alterators are desiged to operate at +0G or so d$ty cycle. heyo$ dri4e the alterator with $ll ip$t 4oltage at K7 yo$ ris da&age to it $less the testis brie.

Test !. lectrical a$lts

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A Bosch alterator has diodes: ! egati4e ad !positi4e power diodesor& the $ll-wa4e bridge

rectiier that co4ert ACto KC. The there are !s&allerisolatioEe8citatiodiodes. The last ! arethe oes that cotrol KHo the 4oltage reg$latorb$t &ost a$to part storesha4e o icliatio otestig the&: they applya 4oltage to K76 spi it

$p6 the alterator p$tso$t 0-100G rated a&psat BH ad they say it3sgood b$t that test does3tpro4e the alterator isworig correctly? theo$tp$t wa4eor& at KHis3t checed yo$ ca3tbe s$re the alterator isworig??? Abor&alo$tp$t at KH is $s$ally

ca$sed by bad diodes.7or e8a&ple6 a high c$t-i rp& is a co&&o side-eect o diode ail$re.

The reaso or testig the s&aller isolatio diodes properly is that whe they ail the ,Rwill be co$sed ad ot ow how to cotrol a alterator that ca otherwise o$tp$t $ll4oltageEc$rret. They pro4ide the 4oltage sigal $sed to deter&ie the battery 4oltage. the test is sipped6 yo$ &ay si&ply get bac ho&e with yo$r alterator6 reistall it6replace the reg$lator o the ad4ice o the a$to parts store ad still ha4e chargig

proble&s. =o$ eed a oscilloscope to detect this witho$t disasse&blig the alterator.

Rate their test proced$re...a co&plete test o the alterator wo$ld cosist o:

rotor coti$ity

stator coti$ity

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$ll ield test or &a8i&$& power o$tp$t (+0 or *0A)

&a8i&$& o$tp$t power $der $ll load (*0A)

4oltage reg$lator set poit (1#,)

4oltage reg$lator set poit hot (te&p co&pesatio)

c$t-i speed (idicator la&p o$t)

o$tp$t wa4eor&

ripple 4oltage O &a8i&$& o$tp$t

rectiier diodes 4oltage drop ad orward c$rret tests

rectiier diodes leaage c$rret tested at 12 4olts

% co$rse6 sice the test is ree6 they oly do the &ii&$&: $ll ield-test.

Kiscoectig the battery while the alterator is r$ig ca ry the diodes iside soe4er do that e4e whe the egie i t$red o. =o$ sho$ld ot do this i order to testthe alterator by seeig i the car still r$s or by checig the 4oltage at the battery. Thebattery also acts lie a h$ge capacitor that s&oothes o$t the power deli4ery ro& thealterator. esiti4e electroics &ay ry i yo$ r$ the alterator witho$t the battery.

Alternator ,ear:

the alterator checs o$t electrically6 yo$ still eed to ispect the parts so yo$ do3tget st$c o the road. Alterators ha4e a li&ited lie beore they re$ire reb$ildig. =o$ca e8pect to get 200 &iles o$t o a actory $it. By that ti&e6 yo$ will ha4e oe or&ay o the ollowig proble&s:

or bearigs

or br$shes

or slip-rigs

There sho$ld be o side to side play i the rotorEp$lley. That idicates yo$r bearigs areshot. there is e8cessi4e edplay it &eas that the rotor is ot press it to the bearigay&ore or the dri4e ed bearig retaiig cap has co&e loose ad the bearig is ologer press it to the dri4e ed plate (ho$sig).

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Bearig replace&et re$ires co&plete disasse&bly. %te the bearigs are so old thatthe grease iside has dried $p6 beco&e cota&iated or o loger cotacts thebearigs. Bearig grease ca dry o$t log beore the e8pected lie o the bearig isreached6 so yo$ &ay ha4e wor bearigs ater 100 &iles i yo$r alterator sat $$sedor &ay years. the bearigs spi easily ad &ae a &etallic rollig so$ds they are

wearig. yo$ hear ay gridig oises they are iished. %ly a silet bearig thatspis dow 4ery $icly is i e8cellet coditio.

or br$shes are a si&ply &atter o replace&et. The br$shes are carbo based ad asprig presses the& agaist the slip-rigs. he the sprigs are $lly e8teded (abo$t#-'&& o wear) they o loger &ae good cotact with the slip-rigs. Br$shes sho$ldbe ispected e4ery *5 &iles o a Bosch alterator.

/$ite ote the sy&pto& o wor o$t br$shes is a a licerig warig light o the dash.

or slip-rigs are a &ore i4ol4ed repair. The slip-rigs are &ade ro& copper ad the

br$shes car4e a groo4e ito the&. =o$ ca t$r the slip rigs i they are ot too wor b$tthe &ileage o the alterator will deped o how &$ch copper is let. At so&e poit theslip rigs ha4e to be re&o4ed6 replaced ad re-soldered to the rotor.

Doise &aily co&es ro& wor o$t bearigs. ith the egie r$ig yo$r caot hearthe oise ro& wor br$shes altho$gh yo$ ca hear it whe yo$ spi the rotor by hadas well as see it o a oscilloscope.