ali125 0 Posted November 27, 2012 Share Posted November 27, 2012 Toyota avensis diesel 2.0HiI put in a new Bosh Battery from Halfords (bought two months ago http://www.halfords....yId_165762#tab1), yesterday whilst the engine was running i had a tomtom satnav plugged into the cigarette lighter, had the heater on, radio. I turned the car off and done my shopping, came back after 10 minutes, turned ignition and car won’t start. My brother done a jump start and the car started again.Went to Halfords, and they said the Battery is fine.Went to a garage and the bloke said the Alternator is ok. He said it might be the starter motor as when turning my engine he noticed a crank. He said the starter motor might be draining the Battery when it cranks as it uses the Battery to turn on the engine.Has anyone had this problem??Would it be the starter motor that is draining the Battery??? Quote Link to post Share on other sites
averageuser 0 Posted November 27, 2012 Share Posted November 27, 2012 Hi!Relying on my experience, possible reasons may be:Poor Battery terminal contacts and/or Battery grounding (simply clean from oxidation and tight up);Battery energy leakage as via starter circuitry as any other way (when key is removed, connect multimeter leads across grounding cable, multimeter set to DC operation 200 mV. reading must not exceed few millivolts;Poor Battery (even brand new);Starter winding is possibly shortened (enormous current consumption). Thank you. Quote Link to post Share on other sites
t-spiritpete 119 Posted November 27, 2012 Share Posted November 27, 2012 Why did you replace the original Battery in the first place, was it the same problem? Quote Link to post Share on other sites
Druid Boy 70 Posted November 29, 2012 Share Posted November 29, 2012 I had a similar experience. Drove for about an hour, parked for about an hour, car wouldn't start. AA chap suggested starter motor was killing Battery as he had to use booster pack as well as jump leads to get it going - it was pulling a huge amount of power. Local dealer diagnosed simple Battery fault so new Battery fitted. Soon ahd the same problem. Dead Battery. Turned out the starter motor was failing and drawing so much power that it was killing the Battery. Got a new Battery under warrnety but had to cough up for the starter motor. Worth getting your starter motor checked. Quote Link to post Share on other sites
ali125 0 Posted November 29, 2012 Author Share Posted November 29, 2012 Thanks for the reply.I replaced the old Battery because of the same problem. Thought this would sort it out. It might be the starter motor. @ Druid BoyIs your car problem sorted after changing the starter motor??? Quote Link to post Share on other sites
Druid Boy 70 Posted December 1, 2012 Share Posted December 1, 2012 Oh yeh. Totally sorted. The starter spins faster and the engine leaps into life. I was surprised by the amount of difference it made. Just be careful though - just because the symptoms sound the same doesn't mean the fault is the same - and starter motors are not cheap. Quote Link to post Share on other sites
garethpaul 22 Posted March 12, 2013 Share Posted March 12, 2013 many toyota starter motors suffer from worn contacts over time which present similar symptoms to that of a dead Battery (just a click when turning the key).I had to change mine at around 100,000 miles.These contacts are easily replaced and parts are available for no more than £10 on ebaySearch Google for "replace toyota starter contacts diy" Quote Link to post Share on other sites
frankie406 154 Posted March 12, 2013 Share Posted March 12, 2013 funny that i just replaced my Battery last week on avensis d4d because she wouldnt start thought Battery was dead as it would even start with jump leads new Battery started right away. though thinking back now then starter did sound a bit lazy on it..must get it tested thanks for the heads up! Quote Link to post Share on other sites
+robster+ 39 Posted March 12, 2013 Share Posted March 12, 2013 most jap equipment i work on have small starter motors that dont last as long as othersthey do put a lot of current through the starter solenoid contacts as mentioned but usually firstly due to a poor Battery on the premise of voltage vs currentlow volts/charge to an accessory cause high current drawhigh volts/charge to accessory cause lower current drawso the moral of the story isthe Battery could have been poor and caused excess heat to the contactsnew Battery fitted problem solved for a while but ultimately contacts are now giving upmay not just be the contacts though as the brushes and armeture will have taken the same current loadingcheapest and best bet is a service exchange from an auto electrical garage who recon rotating electrics £100+vat ish for this if you can remove and fit yourself Quote Link to post Share on other sites
frankie406 154 Posted March 12, 2013 Share Posted March 12, 2013 yeah rob thinking of taking mine out and getting it checked over it sounds lazy but thought that was just a toyota thing as ive heard a few like that.? Quote Link to post Share on other sites
cooper12000 2 Posted March 13, 2013 Share Posted March 13, 2013 ok silly question how does a low voltage cause a high current. ie v/r=i 12/1k=0.012 amps or 12 mA 9/1k=0.009 amps or 9 mA it might be me being thick or is it some weird thevnins (spelling) thing where u put a short across the Battery but it doesnt go bang.not trying to argue just understandcoop Quote Link to post Share on other sites
+robster+ 39 Posted March 13, 2013 Share Posted March 13, 2013 Ohms law bud The power source and wiring arent the whole systemThe starter or other consumer is rated in wattsThe calculation you show is a motor free wheeling which is correct lower voltage will just slow it down but the differences in voltage try ing to push the same thing is where the current differsThis needs to be takeninto the equationIts tried and tested in my line of workPoor tractiion Battery will eat contact tips. Motors. Transistors etctAnother observation on a lower scale is vehicle diagnosticsThere is usually a block measuring Battery voltsThis is to calculate the current neefed to correctly feed outputs such as stepper motors and scv etc The higher a voltage the less current needed to work the consumer to do the same functionAnd vice versa Quote Link to post Share on other sites
+robster+ 39 Posted March 13, 2013 Share Posted March 13, 2013 This may make more sense http://m.ecmweb.com/design/highs-and-lows-motor-voltage Quote Link to post Share on other sites
+robster+ 39 Posted March 13, 2013 Share Posted March 13, 2013 Dont go trying the dead short over a Battery thingNever heard of that theoryIt will melt the wiring or if wiring is ample then Battery will explode especially if its been gassing due to a recent chargeBut put a bulb in series and its ok Quote Link to post Share on other sites
t-spiritpete 119 Posted March 13, 2013 Share Posted March 13, 2013 With regard to a DC motor, the voltage across the motor, minus IR losses, is proportional to the speed or RPMs of the motor. The current through the motor is proportional to the torque produced by the motor. Normally the back EMF created by the speed of the motor opposes the voltage being applied and limits the amount of current the motor draws and thus it's torque. As more and more load is applied to the motor, the motor slows reducing its back EMF allowing more current to flow, producing more torque.With a lower applied voltage to the motor not only will the motor be turning slower, which reduces the back EMF and allows more current to flow, the losses such as the internal Battery resistance, the cable loss and the IR drop in the motor become more important. This may mean that the motor may not have the speed or torque to turn over the engine and stall. When the motor stalls there is no longer any back EMF and all the current goes towards heating up the motor windings and that can damage the motor.Pete. 1 Quote Link to post Share on other sites
cooper12000 2 Posted March 13, 2013 Share Posted March 13, 2013 im just being thick i guess i cant see how somthing can draw more current if the voltage is dropped...i wasnt suggesting trying short circuiting a Battery it was a therom we had to do for my onc it was one of thoes things that i just couldnt get my head around like trig identities i just had to hope it didnt come up in the exams....however i can see that if the current was increased it would burn out the components quicker through arcing and sheer heatthanks for trying to explain anywayscoop Quote Link to post Share on other sites
+robster+ 39 Posted March 14, 2013 Share Posted March 14, 2013 A higher current/ higher load on a component drops voltageThink of your Battery dropping dropping from the 12s into the 9s on your meter when cranking( drawing current)Its just the opposite mirror image of thatThats the last input from me on the subject lol it can get quite deep subject to get intoheres an easy converterhttp://www.supercircuits.com/resources/tools/volts-watts-amps-converterput 12v base Battery figure in voltsput 3000 watts ( 3kw starter) in wattsleave amps blank and press calculate now try 9 volts and 3000wsee if the amps go up or downim gonna have to do some real world tests when i get time, i probably need refreshed on a lot of things as i mix ac/dc charging / powering and i mostly know what the problem is without thinking about it but need to brush up on my terminoligy for each so i reserve the right to look like a fud if ive gone off track with any above. lol Quote Link to post Share on other sites
t-spiritpete 119 Posted March 14, 2013 Share Posted March 14, 2013 A higher current/ higher load on a component drops voltageThink of your battery dropping dropping from the 12s into the 9s on your meter when cranking( drawing current)Its just the opposite mirror image of thatThats the last input from me on the subject lol it can get quite deep subject to get into :lol2: ;) Quote Link to post Share on other sites
cooper12000 2 Posted March 15, 2013 Share Posted March 15, 2013 robster please dont think i was picking at ya i was just trying to learn somthing new:) Quote Link to post Share on other sites
boboo 4 Posted November 18, 2013 Share Posted November 18, 2013 theory right formula wrong not vir but piv common mistake to quote the power formula as ohms law Quote Link to post Share on other sites
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