Battery light stays on..

[getm_up]

hey guys i recently purchased a new battery, when i turn my car on (engine running) the battery light stays on.
i popped the bonnet and pulled off the negative to the battery and the car still runs.

any suggestions?

[sensei_]

have you checked that the battery is good? i have encountered a faulty century battery just outside of the retailer. had them exchange it 1:1 without any dramas.

[JDM-Panda]

When the battery light stays on it means there's a problem with the charging system, the most common cause is the alternator being faulty.

[grifty]

grab a multimeter and check the battery voltage and the charge voltage.

[DC2-PWR]

When the battery light stays on it means there's a problem with the charging system, the most common cause is the alternator being faulty.

+1 rep
Check alternator

[Azz86]

Battery voltage should be roughly 12v with the car turned off. Start it up and it should raise to 13-14v. This means the alternator is charging your battery.

The alternator must be working if the car was running without the battery connected.

[XB-16-AX]

You may want to check the Voltage Regulator.

this can be found inside the alternator or could be external (depends on the alternator design/model).

Voltage regulator - if faulty, can cause irregular charging/battery or electrical lighting issues.

so if this is faulty it will light up the battery charge light on the cluster or flicker any other lights in the car.

[sensei_]

just thinking of this when i was away from computer, maybe check if the brushes are good. often the brushes are worn, and all it needs is a replacement.

i remember my camry having this problem

[ericl33]

Battery voltage should be roughly 12v with the car turned off. Start it up and it should raise to 13-14v. This means the alternator is charging your battery.

The alternator must be working if the car was running without the battery connected.
incorrect, it should be 12.6 when off.

[ericl33]

just thinking of this when i was away from computer, maybe check if the brushes are good. often the brushes are worn, and all it needs is a replacement.

i remember my camry having this problem
not something you can check unless you take the alternator out.

[sensei_]

depends where the alternator is i guess. on the camry is was smack bang in the middle of the car, just to the left of the oil filter, so checking that was a piece of cake (for me!).

on the legend, it will be a pain in the butt to check because it is buried just under the engine, with the fans blocking its path

[ericl33]

depends where the alternator is i guess. on the camry is was smack bang in the middle of the car, just to the left of the oil filter, so checking that was a piece of cake (for me!).

on the legend, it will be a pain in the butt to check because it is buried just under the engine, with the fans blocking its path
All the D series & B series motors I've seen have alternators in a hard to see spot.

and it seems he has a 96' EK (poor guy) sedan

so it would be safe to assume he needs to take it out.

[Azz86]

incorrect, it should be 12.6 when off.

Well it is correct. Lead acid batteries are never spot on. A new battery should be over 12v but an older one will deteriorate to a value below 12v.

[ericl33]

Well it is correct. Lead acid batteries are never spot on. A new battery should be over 12v but an older one will deteriorate to a value below 12v.
it should be 12.6v

it should NOT be 12.1v, 12.2v or below 12v

if you're getting those figures you should give it a charge or replace it.

you're not correct.

[Azz86]

it should be 12.6v

it should NOT be 12.1v, 12.2v or below 12v

if you're getting those figures you should give it a charge or replace it.

you're not correct.

Alright mate. Only been an electrician for 9 years but no worries.

[ericl33]

Alright mate. Only been an electrician for 9 years but no worries.
:thumbsup:

I only DIY work on cars & DIY home electrical.

9 years > me.

[XB-16-AX]

:thumbsup:

I only DIY work on cars & DIY home electrical.

9 years > me.


im only 9yrs+ noob and only ever had/owned turbo cars ...only honda for 1yr.

:)

[Azz86]

:thumbsup:

I only DIY work on cars & DIY home electrical.

9 years > me.

Sorry bud. Not trying to be a d!(& or anything.

Your absolutely right in saying a battery should be at 12.6v. A new battery will be around that voltage. But an older battery could be at 12.1v and still be fine. Remember 0.6v is only 5% which is most likely what the manufacturers tolerance is.

If a battery is heat affected or has suffered from long periods of being discharged you will be able to tell from the voltage if it is f@(&$). It will drop below 11v and will drop significantly under load. Also won't hold charge.