Last week I noticed my battery light flicker once or twice, I didn’t think much of it, just watched it carefully from there on. Figured I left interior lights on by accident and drained it a bit.
Well, last night I started my car up, rolled down the windows and when I turned on my headlights I lost virtually all power. headlights dimmed to almost nothing, radio turned off, dashboard lights gone and windows only go up extremely slowly. The battery light might have come on, but who knows? the whole dashboard was dark… I could hear and feel my engine straining, it wanted to stall if I didn’t give it gas. finally got the windows up in case it rained and left it parked till next day when I got a friend with AAA gold to tow it(I know, I know, I’m a horrible person…)
When we got to the garage, the mechanic started it up no problem. He checked it out and said there was nothing wrong with it of any significance. The idle pulley and tensioner were a little tight, but he said he wouldn’t recomend replacing them. That wouldn’t cause the near catastrophic electric failure I had last night anyway. I should bring it back when the electric problem persists he says. YES!!! I love driving a ticking time bomb!
OK, tonight I unlock my car, noticing my power locks strugle to unlock, “Bad sign” I thought to myself. I started with very little trouble and a mile down the road the battery light goes on. I downlshift and when I get the rpms over 3k it goes off. I managed to get home and parked facing downhill in front of a drive way so I know I can coast out and do a rolling start.
So now for the questions…
a) Is the mechanic I went to an idiot?
b) Is it the alternator, battery or what? I want to be armed with info when I go to another mechanic.
c) Out of curiosity, assuming the battery is near toast, at what rpm would an alternator need to spin to run the car, headlights and radio?
With my pitiful knowledge of cars – hey I changed my serpintine belt once, just had to borrow an engine jack cause the retarded engineers at ford decided to put it around the engine mount, way to go ford! – I would think 3000 rpm would be a little high
Oh, I just got the belt tensioner and alternator replaced last year…
We don’t know what the mechanic checked, so let’s start from the beginning.
Both ends of each battery cable should be checked and determined that it has good clean tight connections. This is especially a problem with side connection batteries.
Many auto part stores will check the battery and charging system for free. They generally do a good job and will accurately catch most problems.
If you go to a mechanic, don’t try to tell them what to do, rather your only part in that is to tell them why you came to them. You tell them what you have personally observed and not what you think that means.
a) Why do you think the mechanic is an idiot? If the problem was not there for him to see, it is not his fault if he cannot find it. Electrical problems like this can be hard and time consuming to find. Especially if they are intermittent problems.
b) I believe it is the alternator. The battery light is actually a signal from the alternator that something with the charging system is wrong. If the engine starts right up, the battery is holding and releasing charge. Another possibility is a short somewhere else killing the voltage for the whole car. But, this normally would cause burnt wires or even a fire. The battery is capable of releasing enough voltage to weld with. Only the wire to the starter is able to contain that much power. Also, there may be a problem with the fuse box. A 9-year old car is getting to the age where fuses and connectors can cause all kinds of little electrical gremlins. Not all cars suffer these problems, but some are more susceptible than others.
c) Even with a totally busted battery, the alternator at idle should produce enough power for everything. That is why I suspect a bad alternator. I’ve jumped cars with absolutely no juice in the battery, and no capacity to hold a charge, and it ran just fine after starting it, even running lights, wipers, radio, all at idle.
Did your mechanic actually connect perform a test to evaluate the charging system. Places like Walmart do this for free.
I asked if was an idiot because he said nothing was really wrong, if he said he couldn’t “find” anything wrong, I wouldn’t ask if he was. I’m also stressed over this because I had to cancel a trip this weekend. Getting towed off the turnpike is a financially scary proposition. Basically just pissed and venting.
I assume he did hook it up and perform a test on the charging system. He quoted amperage to me with and without the lights on, which he said was fine. Maybe there’s a problem getting the charge from the alternator to the rest of my car. I don’t know. Something causing the headlights to drain much more power than they should? Regardless, it’s sitting at a different garage now waiting to be looked at.
I think you may have touched on the problem with your statement about the power from the battery and the rest of the car. There very well my be a connection problem between the battery and the main power panel under the hood. If the battery is getting charged properly and is in good shape then it sounds to me the problem is in the main power buss to the accessories. It should be pretty easy to find it. Tapping on suspected areas while watching the lights may help locate it.
HUZAH!!!
I now have a fully electrified car, and a new mechanic to boot. He’s only a two minute walk from my house, didn’t even know he was there for two years. Anyway, turns out it was just the alternator all along. New guy said it was running 6 volts/amps whatever under full load, now it’s 13.5 so happy day, Pittsburg here I come!
Turns out the last mechanic was an idiot after all, since he hooked it up and quoted amperage at me. Unless an alternator can not charge one day, charge the next, and then not charge the following day.