I thought it could be the alternator but I heard that the car would not run for very long, and I know that once the car is charged it will run fine until parked up for a couple of nights, and then it is as flat as hedgehog on the A1. Can anyone help????
2007-01-21 05:28:58 · 8 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
It's easy enough to check if the alternator is charging by putting a volt meter at battery terminal, should read about 12.5v with car off and between 14-15v while running. You have to determine this first, if charging then you have a bad battery or a draw on battery while it's parked.
2007-01-21 05:35:19 · answer #1 · answered by wheeler 5 · 0⤊ 1⤋
Charging System Basics: The electrical system in an automobile is said to be a 12 volt system, but this is slightly misleading. The charging system in most cars will generally produce a voltage between 13.5 and 14.4 volts while the engine is running. It has to generate more voltage than the battery's rated voltage to overcome the internal resistance of the battery. This may seem strange, but the current needed to recharge the battery would not flow at all if the charging system's output voltage was the same as the battery voltage. A greater difference of potential (voltage) between the battery's voltage and the alternator's output voltage will provide a faster charging rate. As long as the engine is running, all of the power for the accessories is delivered by the alternator. The battery is actually a load on the charging system. The only time that the battery would supply power with the engine running is when the current capacity of the alternator is exceeded or when engine is at a very low idle Some people tell you that you can check your alternator by disconnecting it from the battery to see if the alternator can produce enough current to keep the engine running. Disconnecting the battery will subject the voltage regulator (and computer and audio equipment...) to significant voltage spikes which may cause an otherwise good alternator to fail. Even if there were no damaging spikes, this test would not indicate whether or not the alternator was good because the engine will easily run with a weak or failing alternator. Simple Test: If you want to see if your alternator is producing current, turn on your headlights when you're parked and the engine idling with the headlights shining on a wall (at night). Notice how bright they are. Then turn the engine off. The lights should get dimmer when you turn the engine off. If the lights get brighter when you kill the engine, the alternator was not charging sufficiently. When doing this test, the lights should be the only load (turn the stereo, a/c and other accessories off). With a heavy load, an otherwise good alternator may not be able to produce sufficient amounts of current at idle.
2016-05-24 05:59:24 · answer #2 · answered by Anonymous · 0⤊ 0⤋
it's probably some connection problem. You could check if there's a drain with a multimeter. I'd pull the alternator off and check that the earth off it (maybe the bracket) is clean. I had the same problem on my old bmw 325, it was allowing enough charge to keep the battery light out, but not enough to charge the battery. took me 4 weeks to figure it out - practically tore the car apart !
2007-01-21 20:28:02 · answer #3 · answered by spooky 2 · 0⤊ 0⤋
Sounds like the alternator is faulty,a wee test you can do yourself
is wait for darkness switch off all electrical items, keep ignition off,disconnect negative lead from battery if it sparks then something on car is using power.
2007-01-21 05:37:06 · answer #4 · answered by Anonymous · 0⤊ 0⤋
maybe you are leaving an interior light on ? the one in the boot may be on and you havent noticed...or you have a "short" somewhere ?? summat is draining the battery a good garage will have the nous to find out why...hope iv helped a little (",)
2007-01-21 05:34:49 · answer #5 · answered by sp4nna 3 · 0⤊ 1⤋
take the car to an auto-electric repair mechanic and quit messing around --- you could have the car die on the freeway and get seriously banged-up or someone else hurt .. if the car gets fixed properly then everyone gets happy ... ....
2007-01-21 05:36:15 · answer #6 · answered by XTX 7 · 0⤊ 0⤋
try checking to see if the boot light or interior lights stay on when they should be off. if your lights brighten up when you rev the engine up then the altenator should be ok .or get some one to check the charging system properly
2007-01-21 05:39:47 · answer #7 · answered by smokie 1 · 0⤊ 0⤋
short out some where?
best bet electro enginiere not mechanic
2007-01-21 05:35:34 · answer #8 · answered by witheringtonkeith 5 · 0⤊ 0⤋