Technical Car turned off when I turned the headlights on

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Technical Car turned off when I turned the headlights on

Balak

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I drove to work this morning (20 minutes, 10 miles) and it was fine with the headlights on.

Then when it was time to go home, the car would not start. Electrics came on and gauges where flickering, I could hear ticking. I'm 100% sure no lights had been left on.


My FM radio transmitter thing also tells me the voltage. It was down to 8.5V. I had to get it jump started and was advised to let it idle for an hour after getting home. So I did with all electrics turned off and slight gas to get it to 1500-2000rpm. At this point, I was seeing a voltage of 14.3V at high rpm and 13.8 on fully idle.

When I looked closely at the screen, I could see a very faint flicker that went away at higher revs. While fully idle, I turned the headlights on and the power cut out. Car wouldn't turn back on and the voltage read as ~8.5V.


Is the alternator bad? Is the battery bad? Is the driver bad?

Any help much appreciated. Thanks.
 
Thanks for the speedy response.

I'm too upset to look at it now (it's also dark outside). Cleaning the terminals didn't help but I'll try checking for Earths tomorrow.

It's just crossed 70,000 miles today.

I'm so lost. It's like a dead brick on the driveway - do mechanics do home visits?
 
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To clarify, I don't actually have a voltmeter. What I have is a cigarette lighter fm transmitter that also displays the voltage.

When the key is turned halfway, the reading is now 8.9V. But when the engine was on, it read up to 14.3V.

I've not had battery drain problems before. The start/stop function doesn't work. Perhaps that's relevant.

Also, when I tried to start it and it failed, attempting to then turn the radio on and USB charger caused the airbag warning to come on.

Should I quickly order a mains battery charger from ebay (~£15)?
 
To clarify, I don't actually have a voltmeter. What I have is a cigarette lighter fm transmitter that also displays the voltage.

When the key is turned halfway, the reading is now 8.9V. But when the engine was on, it read up to 14.3V.

I've not had battery drain problems before. The start/stop function doesn't work. Perhaps that's relevant.

Also, when I tried to start it and it failed, attempting to then turn the radio on and USB charger caused the airbag warning to come on.

Should I quickly order a mains battery charger from ebay (~£15)?

Most likely issues are:
1/ Bad battery
2/ Bad negative "earth connection"
if you have jump leads connect one from battery negative to the enging block or gearbox case. Connect the second from the engine block to the bodywork.
If it now starts you have bad earth connection, get a new cable. If it dosen't work try a new battery. An auto electrician will do a call out to your house but get a price for the call out and a new battery before you commit. It might be cheaper to just buy a battery and try it.
A charger is not going to help, if you buy anything before a battery it should be a cheap multimeter.


Robert G8RPI.
 
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Update:

I managed to get a jump start today so I went straight onto the motorway and drove with the sidelights on. Absolutely no problems, felt completely normal.

After 10 miles, I turned off the motorway and onto a 50mph route back home. Along this road is where I first felt the car jolt back a bit. Then this kept happening about every five seconds. Speed gauge was all over the place, instrument lights were going off and on. Battery warning light was coming on.

This was not the kind of road I wanted to breakdown on so I turned the lights off (it was safe to do so) and I kept going. Hill start assist warning also came on, I did not think I had this feature on this car...


Thankfully I got home and let the car idle for 30 minutes. I could not see anything wrong with the alternator belt. It was spinning fine and didn't sound weird.

When the radiator fan would spin up, the instruments lights would momentarily dim.

For some of this time, I held it in neutral around 1500rpm. When the radiator fan would wind down, the rpm would jump up to about 2500.

At 3000-4000rpm, I was able to turn the full headlights on.

After a total engine on time of 90 minutes, I turned it off and tried to open the boot but it wouldn't. I could here the little motor trying. Doors didn't lock the first time either.

Based on this, I'd say the alternator is fine but this battery should be replaced?
 
Thanks guys.

I'll go and buy that battery! (will be a couple of weeks until pay day though when I can afford it)

It's so nice to have this active community here where I can turn to in times of need. I wish I had more experience to return the favour. Soon :)
 
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