focus 2004 battery light

I'm sure someone on here will know what's wrong


ford focus 2004 diesal 1.8 tdci

battery light comes on after 30 seconds. been driving it for weeks with this fault. obviously front windscreen demister is disabled because of this.

a few days back I started car in morning. switched on back demister electric. dropped little one to school. got back in car and car failed to start. not enough juice.

jumpy started it and drove but electrical power kept cutting off. needles going haywire etc.

got it at home now. plugged into mains and left it to chsrge the battery via an extension lead out of the window. seems to be starting fine now.

not sure what the fault is. some say battery others say alternator. with some saying smart charge harness.

any ideas or what I should be testing. don't want to fork out 100 quid for a battery if that isn't at fault.

any ideas guys?

might be worth topping up battery with some de ionised water dropping in a couple of granville bat aid tablets in each cell and giving it a recondition charge with a smart charger such as ctek mxs 5.0
I think it should be 14.4 volts whilst the engine is running

Once it's charged, put a volt meter on it. It will probably be reading about 12.5v or higher.

Also check when it's plugged to the car before it's started, voltage should drop much.

Once the car is started, voltage should rise to about 13.5-14.5ish (not more than 15v).

If voltage is rising when car started then probably battery problem.

If voltage not rising when car started then probably alternator or maybe this smart charge thingy.

I would allso check the earth strap from a the engine to the body

Battery warning light is the alternator. 100%
It could be simple like the rectifier or regulator has gone.

Quote:

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Originally Posted by Teajunkie

Battery warning light is the alternator. 100%
It could be simple like the rectifier or regulator has gone.

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Yep.

Take it to any decent battery centre and they'll check the draw and recharge for free
AA or RAC will do the same for you.

if it has 3 thin wires from alternator ,give them a pull one at a time .often the blue one breaks
Russell

thanks for all your tips guys, will find out in a few days time when I get a chance to take it to a garage,
lets see what they say

been starting fine after charging up the battery but dare not take it out for a spin until its sorted properly, :)

red one had broke

main fault was the alternator . put in a reconditioned one and all sorted

198k on clock now. place your bets on how long the car will last ;)