10 replies to this topic

[paulinsuffolk]

Hi all.. my first post here and it's technical.

I've got an 2003 focus 3-door 1.8 zetec which was absolutely fine until the original alternator went pop last year. We took it to a garage and they fitted a replacement... that lasted 6 months then fried it'self.!

We've now had another alternator fitted..(... both are RTX units) but now when the cars ticking over at night the lights are going from dim to bright quickly as if there's not enough power at tickover to keep a constant light, electric windows are slow (lift the revs and they're ok).. and sometimes the battery light comes on even at speed.. but the worst problem is that the battery saver relay behind the glove box is clicking like crazy.!!

Irrispective of whether you're doing 70mph .. or ticking over in the drive, but as soon as you give the alternator something to do and put it under load.. ie, put the front & rear screen de-misters on.. the clicking seems to stop.

Rather than suggestions of what it might be, i'd be over the moon if someone could give me a genuine technical explaination 'before' i take it along back to the garage who did the work. I'm thinking the alternator isnt man enough for the job ..or it's faulty, and it's confusing the smart charge system with irregular voltage supply. Battery is 12.8v standing cold.. and 14-15v engine running

Cheers guys .. appreciate your help.. Paul

[FOCA]

Is a silver calcium battery fitted?

[paulinsuffolk]

Is a silver calcium battery fitted?

Not too sure.. but it is the same one thats been fitted and worked 100% perfect for the last 20k miles with the original alternator.. and the 1st replacement alt.. the only thing thats changed is those alterntors

[artscot79]

if the wron g battery is fitted it will fry the alternator

[paulinsuffolk]

if the wron g battery is fitted it will fry the alternator

How would it do that Arthur .. wouldnt the smart charge system pick that up and regulate charge to the battery and not cook the alternator.

[artscot79]

the alternator will send the charge to the battery if its a lead acid battery then the extra charge will be fed back through the wiring to the alternator this is why it must only use silver calcium batteries so yes the constant feedback to the alternator can cause the smart charge to fail this leads garages to replace the alternator but most have no idea about the battery or that silver calcium is needed so the battery type is the first port of call after that if its okay then a ford dealer should look at the wiring the smart charge doesnt assume youll have the wrong battery in so no it will attempt to put the charge in

[paulinsuffolk]

Wouldnt the diodes in the alternator (after converting from A/C to D/C) effectivly block any power coming back and so only allowing the power to feed one way.. and when the battery has enough power, the regulator (beit smart charge or alternator controled).. back off the charge from the alternator.

Either way.. this battery was fitted to the car when we bought it, we've now done in excess of 20k miles on that battery and original alternator before the bearings went.. the problems started when replacement alternators were fitted.

PS . The lastest... last night both dip beams blew and the ABS light came on and the speedo/rev needles went crazy.! Really could do with a electics tech/wizard.. is there one here on this forum.?

[artscot79]

it doesnt work like that im afraid the diodes will do nothing its not like any other smart charge system in use the battery can take many many miles to cause the issue i still think the battery needs to be looked at first once that has been checked then you need to look at the wiring for the smart charge there are 3 wires if any of these were damaged you have an issue if im honest get it to a dealer it sounds like the alt is putting out way too much current which it will do if the battery cant cope

the smart charge puts max voltage 18v into a cold battery that needs charged mainly on a healthy battery 14.4v max as the electrolyte heats up in the battery cells the silver calcium plating is used and sends a signal back to the ecu this in turn drops the voltage from tha alt to the battery if the battery doesnt have silver calcium in the electrode posts then the system does not recognise any signal from the battery back to the ecu and will keep charging at max voltage this boils the electrolyte and eventually the electrolyte gets so low the voltage feeds back causing the smart charge to blow out this results in over charging or not charging enough dipped beams blowing means the system is pumping out way too much voltage so either the alternator is the wrong make or type for the car the batery is incorrect and causing these issues cheapest item to check and rules it out no matter how many miles the cars done or the wiring was damaged upon fitting the new alternator either way a garage who knows how to examine the wave form data from the alternator is needed which is a ford dealer if you want it fixed its not a do at home job and will need a dealer to look at it

[paulinsuffolk]

I've just checked the battery and it's a Motorcraft Superstart, which i understand is the correct battery fitted by Ford.. it also has the 'Ca' marking on it which in the handbook means silver/calcium. This morning in the cold and without charge from running.. it's 12.7v.

Like i say, i'm going back to the original garage as they need to be given 1st chance to offer a repair (not trying to fix it myself, just want to be armed with enough info as possible) if they cant diagnose a fault then yes it will go to Ford main dealers for a fault code reading and repair.

After all this It still doesnt explain the battery saver relay clicking and the other probs... only that when you search the net for Focus RTX alternators.. they replies and feedback for that manufacturer are terrible along with ''do not buy''.. lol.!

[artscot79]

Okay so the battery is fine that would suggest either the alt is faulty though the battery voltage seems fine so it may be overcharging the relay may be sticking worth changing it just to seevwhat happens the alternators are ok the smart charge is very misunderstood and garages keep swapping alternators when other issues like batteries are involved personally i think they have damaged the 3 wire plug which is the smart charge wiring its easy to do and a known issue on that year of car

[paulinsuffolk]

Last year when this first started i checked the 3-pin socket and readings were fine at the time, giving the correct voltage... as you say it could be damaged after the work they've done.. and those wires 'can' break further up that little loom. I'll try another check when it's a bit warmer.! I swapped the relay with another but it still gave the same problem... stops when you give the alternator load though, like heated windows. Strange one this... but apparently not un-common.