Feista problems

slothmeister · 29 Nov 2008 at 19:19

Hi guys,

My poor little feista is on it's last legs, 98 plate with 102000 miles on the clock, loads of probs in the last few months, the latest being that it either doesn't charge the battery or the battery doesn't hold its charge difficult to work out.

So i charge the battery, drive around for a day, leave it for a day, i go to start it and the battery is dead, so have to charge it again and the cycle continues.

I'm reluctant to change the battery as i can't really afford to do it at the moment, i know their cheap but still, especially if it's not at fault. Could it be the alternator not charging the battery? should a battery lose it's charge that quick. There doesn't appear to be anything draining the battery.

If it's the alternator, is that a user serviceable part?

Hope you can help!

Barry Smalley · 29 Nov 2008 at 19:31

Is the red battery light illuminated whilst you are driving?

Wicksta · 29 Nov 2008 at 19:34

Is this the 'I before E' fail night tonight or something?

Fiesta
Rieger

slothmeister · 29 Nov 2008 at 19:45

lol fiesta then!

Nope, no battery light when driving!

Wicksta · 29 Nov 2008 at 19:53

If you have a friend with an multimeter get them to test the voltage while the car is running. Annoyingly the alternator failed on my MG ZS and I didn't get a battery light appear, I noticed the dashboard start to fail (Rev counter, and a few lights came on like the ABS one) and luckily made it home.

slothmeister · 29 Nov 2008 at 19:55

say i can get my hands on a multimeter, what would i be looking for having never used one.

Barry Smalley · 29 Nov 2008 at 19:58

You need to have it at a certain rpm for it to charge anyway. Go and get a battery from the scrappy for a tenner. It's likely to be this.

Finglonga · 29 Nov 2008 at 20:25

Barry Smalley said:
You need to have it at a certain rpm for it to charge anyway. Go and get a battery from the scrappy for a tenner. It's likely to be this.

Once a certain RPM is reached at start up (around 1500rpm) it will be charging on all revs.

Does sound like your battery is mullard. Have oyu checked the levels?

slothmeister · 29 Nov 2008 at 20:38

Finglonga said:
Does sound like your battery is mullard. Have oyu checked the levels?

que? how?

will probably try and lay my hands on a battery tomorrow.

Barry Smalley · 29 Nov 2008 at 20:45

Whip the caps of the battery and check you have fluid above the plates - at least 1 cm.

Finglonga - hows that work then? Why does it need to hit 1.5k rpm first?

slothmeister · 29 Nov 2008 at 20:52

:O didn't even know that you could, or even should for that matter, do that.

Barry Smalley · 29 Nov 2008 at 21:04

Nip up to Halfords and save yourself the hassle - they'll also check the condition of the electrolyte.

Finglonga · 29 Nov 2008 at 21:08

Barry Smalley said:
Finglonga - hows that work then? Why does it need to hit 1.5k rpm first?

Dunno how it all works, did a project on alternators years ago and we were asked to get some juice out of it. It was from a 3.00 Capri and wouldn't start charging until the thing passed 2500RPM! Couldn't remember why but found this to jog my ageing memory . .

A one wire alternator has a turn on point (sometimes called “cut in”, which is typically 1200 engine RPM’s). This is the speed where the internal sense circuitry connects the battery to the voltage regulator, thereby turning the alternator on. Once the voltage regulator turns on, the alternator will remain on and charging until the engine comes to a complete stop. If the engine idle speed and pulley ratio combination do not allow the alternator to come up to this point during starting, the engine will have to be revved up to turn the one wire alternator on. The sense circuitry in the one-wire regulator can be bypassed to excite the alternator as soon as the ignition switch is turned on. This is called three-wire operation. This means the alternator will not be dependent on reaching a certain turn on RPM.

Barry Smalley · 29 Nov 2008 at 21:11

I never knew that. Nice one.

Howard · 29 Nov 2008 at 22:15

The alternator will generate about 14.5v at any engine speed. The battery's probably just knackered, replace it, they don't last forever

BigglesPiP · 29 Nov 2008 at 22:20

What is potential difference between the centre of the positive battery terminal (use black test lead), and the clamp around the positive battery terminal (use red test lead)?

This will give an indication of whether the battery is accepting charge.