Battery light staying on over 4,500 rpm

Battery light staying on over 4,500 rpm

Author
Discussion

Hawkinsster

Original Poster:

169 posts

175 months

Friday 10th June 2016
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Could this be an alternator issue maybe? It's annoying as when I boot it, the light flicks up and it's distracting especially at warp 5.

Any help would be great.

Anthony

Adrian W

13,858 posts

228 months

Saturday 11th June 2016
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Is the battery charging ?

Midlifecrisis71

2,870 posts

275 months

Monday 13th June 2016
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Probably the regulator on the back of the alternator, its job is to take the current produced from the alt and send only 14volts to the battery, if its only over 4500 revs then its probably overcharging the battery and the lights coming on.

Alternatively, ive seen this happen on a Noble when on track, it gets too hot and the light flickers on and off until it cools down again

Hawkinsster

Original Poster:

169 posts

175 months

Tuesday 14th June 2016
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Hi there,

The battery is on a trickle charger when im not using it so it should all be charged. Never had a problem starting her up.
It does ut all the time even when the car starts so its not heat.

I wander if its a loose connection but its when your boot it and the revs wind up.

If it is what you mentioned, is it an easy job,?

Many thanks

Midlifecrisis71

2,870 posts

275 months

Tuesday 14th June 2016
quotequote all
Hawkinsster said:
Hi there,

The battery is on a trickle charger when im not using it so it should all be charged. Never had a problem starting her up.
It does ut all the time even when the car starts so its not heat.

I wander if its a loose connection but its when your boot it and the revs wind up.

If it is what you mentioned, is it an easy job,?

Many thanks
If I were you, I would get a cheap multimeter (£10 from ebay or Halfords) disconnect your charger. Connect the two wires of multimeter to the battery (should read 12-12.6v) then start the car and see what happens to the reading. It should go up to 14volts, then see what it does when the light comes on the dash.

If it goes over 14 volts, or stays at 12-12.6V then the alternator is playing up.

Unfortunately its not easy to remove the alternator. Took me 3 hours lying on the garage floor but that is slow DIY pace. And it was first time removing battery etc

Hawkinsster

Original Poster:

169 posts

175 months

Tuesday 14th June 2016
quotequote all
Ok fantastic thank you for the assist, ill get that done this week.
If it does turn out to be the alternator, is the car going to eventually not start? Ive got a road trip soon and just thinking if this could balls that up. I love the car but as soon as theres a problem it has to go all the way to flipping Leicester. Its never easy.

andygtt

8,344 posts

264 months

Wednesday 15th June 2016
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IF the alternator has failed and is overcharging then it could cause lots of very expensive damage.... Tuxman had this happen recently and it fried his clocks, ecu, gps camera system etc etc... many thousands of pounds of damage.

Its worth getting it checked... as above simply buy a cheap volt meter and monitor the volts when the car is running, give it some revs to 5000rpm and see whats happening, if Volts go silly high then don't drive it.

Adrian W

13,858 posts

228 months

Wednesday 15th June 2016
quotequote all
andygtt said:
IF the alternator has failed and is overcharging then it could cause lots of very expensive damage.... Tuxman had this happen recently and it fried his clocks, ecu, gps camera system etc etc... many thousands of pounds of damage.

Its worth getting it checked... as above simply buy a cheap volt meter and monitor the volts when the car is running, give it some revs to 5000rpm and see whats happening, if Volts go silly high then don't drive it.
It is important to measure both AC and DC volts, as both could damage electronic parts, but if faulty will provide the failure mode of the alternator