Battery running down ?

L

lancermr

New Member
Guys, i have a suspission that my near new 12 volt car battery is running down in volts due to something electrical. if the vehicle is left for a few days the battery does need a charge up for starting of the engine. i had an alarm fitted which i now have disconnected thinking it could have been draining current whilst sitting but just today i did charge the battery up to approx 12.80 volts and every hour i checked the voltage with a multimeter and noticed a drop of around .10 per hour, the voltage at present is 12.44. i also did disconnect the terminals and checked voltage drops per 1/2 hour and there was a slight drop per test. i took the battery back to place of purchase and they checked it with some fancy unit and the read oput said; needs a charge up. i mentioned to them it has only just been charged and its loosing a slight percent per every hour , they will charge this up overnight and test it tomorrow so we will see what happens but as mentioned i still have a feeling something else is draining the battery, any ideas ?
 
Anything that runs whist the car is turned off will drain power. So alarm system could be a chance... just go through step by step in your car and find what is running after you take the key out. A blown fuse or a short may be causing it to just waste electricity.
 
the battery is approx 2 months old [ century brand ] nothing is left on in the vehicle , even checked to make sure the boot light wasn,t on when boot closed.
 
prob a faulty battery, dropped a cell or something along those lines.
its happens quite often, the test machine the shop used should be able to tell them that. that's if they know how to use it.
if its dropping even while disconnected its not your car.
 
just re checked the voltage with another battery fitted and at 4.30 o,clock it read 12.74 volts and at 5 o,clock it read 12.72 volts, is this normal as in a drop and total voltage for this 12 volt battery ? just like to know what the normal voltage should read.
 
have you got any aftermarket lights or amps ect fitted?
your stereo, clock, alarm and other bits and pieces will use some power when the car is off for memory ect.
what is it charging at when the car is running?
what is it charging at when the car is running with all lights and stereo on?
does your multimeter have charged batterys? otherwise it can give a false reading.
again i would almost say it has dropped a cell being that it was still loosing charge once it was disconnected.
i wouldnt be to concerned with a 0.02v drop unless it was constantly dropping.
 
its too dark to test more now but tomorrow morning i will test the voltage of the battery then hopefully statr the engine and test charging current with and without lights on. i did do the alternator charge test the other day and think it was putting out either 13.8 or 14.8 volts with engine running and no lights on.
so to me the alternator is charging well . will let you know tomorrow what readings i get. thanks.
 
just got the battery back and they charged it overnight and it tested up well [ so they say ] they told me these Century Brand Batteries need to charged up for up to 48 hours so they get full capacity . i know i did only charge this up for about 3 hours after it went flat in the car but the car started up well and then i drove for about half an hour , so why did this so called good battery drop its voltage levels by say .o2 volts every half hour even whilst disconnected from the car leads ? was it just under charged and couldn,t gain a full charge from the alternator that is putting out approx 13.8 volts with engine idleing. got me stumped.
 
Is it a calcium battery? Calcium batterys have troubles charging up when flattened low by the alternator, when u flatten a calcium battery you'll need to throw an actual charger on it. Taxis do this all the time.
Also wen u suspect a drain, put an ammeter in series with your battery terminal and anything over .06amps is no good, this will eventually flatten your battery
 
can,t see any words on this battery stating Calcium. its just the normal Century heavy duty wet cell battery , cost me approx $125.
 
its the serviceable type battery ie; 6 x caps under a lid. just checked this new battery and it is holding charge very well, just under 13 volts and the old battery which is in car and connected is reading 12.63 volts after sitting for 24 hours. so all i can now fathum is 2 things; the alarm system must have been draining batt power whilst sitting plus my batt charger wasn,t left on long enough for a good re charge between drives.
 
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