Battery overcharging - Dash warning lights

[stephenusername]

Ford fiesta 1.4 2002 year.

battery warning light started lighting up on dash intermittently and when this happens the battery does not charge. Started getting worse and other lights stared lighting up, air bag, lost speedo/rev and mileage counter. When this happens under the dash to the right of the steering one of the back boxes starts to make a clicking noise. Took it to a auto electrician whom said the battery is overcharging at about 15v which according the other forums can cause the dash light problem. The auto electrician tested the wiring continuity between the battery, ECU & alternator. He then changed the alternator but still the same problem. The last thing he said which could be the cause is a faulty ECU. I sent the ECU of for testing and the ECU is fine. The car also has a brand new battery. Any suggestions will be appreciated.

[btmaldon]

What type of battery is on there? Hope its not a Lead Acid battery. That would cook with the Smart Charge system.

[Russ]

The smart charge system on fords will charge the battery at a higher voltage if the voltage on your battery is down. As the above post, is it a calcium battery on the car and how old is the battery as it may be on its way out!

http://www.valeoservice.com/data/master/webfile/2945759434DDE6E8714173.pdf

[Tdci-Peter]

6 hours ago, stephenusername said:

auto electrician tested the wiring continuity between the battery, ECU & alternator. He then changed the alternator

It seems unlikely that a 2002 Fiesta has smart charge. It is probably just the standard fixed voltage charge at 14.5v (about).

I hope the electrician properly tested the battery. If the system voltages are getting high enough to make modules malfunction, it is likely to be the battery or its wiring. New batteries can fail sometimes.

Any problems starting? Try turning max electrical load on (headlamps, demister, etc) for a minute or so, then starting the car.

 

 

[stephenusername]

I have a Bosch S3 battery. Cannot find what type of battery it is. This is the second battery I have just bought in 9months. The first I killed by the intermittent charging. The electrician checked the car with first the old battery and then the new battery once the new alternator was installed. I looks like it could be wiring.

[Russ]

1 hour ago, Tdci-Peter said:

It seems unlikely that a 2002 Fiesta has smart charge. It is probably just the standard fixed voltage charge at 14.5v (about).

I hope the electrician properly tested the battery. If the system voltages are getting high enough to make modules malfunction, it is likely to be the battery or its wiring. New batteries can fail sometimes.

Any problems starting? Try turning max electrical load on (headlamps, demister, etc) for a minute or so, then starting the car.

 

 

Ford have been using calcium batteries & smart charge since 1997 apparently although not sure if this will include the UK 

http://www.yuasa.co.uk/info/technical/silver-calcium-batteries/

[Tdci-Peter]

1 hour ago, Russ said:

Ford have been using calcium batteries & smart charge since 1997

I must admit, I had assumed that the smart charge came in later than that, and that my 2006 Focus did not have it! But a bit more research suggests that all Mk2 Focus, and possibly some Mk1, have this type of charge system. Learnt something there, thanks for that!

One reason for my assumption is that, whenever I have monitored it, my car reads about 14.2 to 14.6v with engine running. (I have in-car voltage monitoring, though the display is usually switched another channel. I will watch it a bit more, now)

But the Fiesta 4th generation covers 1995 to 2003, so it may not have had it. You would have to look at the alternator plug, or a wiring diagram, to find out.

1 hour ago, stephenusername said:

I have a Bosch S3 battery

I don't think the Bosch S3 is "silver calcium". The S5 claims to be a calcium silver alloy, and it is what I have. I have not checked the S4. The difference is not that great, they are all lead-acid, including Calcium, Silver-Calcium, AGM, EFB, and SLA or VRLA types. Manufacturers claims vary. But there are small but potentially important differences in charge voltage & temperature characteristics.

Back to the subject of voltage monitoring, a plug in meter may be a very useful thing to have, if there is any suspicion about the charge system. Being able to monitor it while driving, as the engine warms up and the battery gets back to full charge would be useful. Something like this: http://www.ebay.co.uk/itm/LED-Car-Auto-Battery-Electric-Cigarette-Lighter-Voltmeter-Voltage-Meter-Tester-/271523172388?hash=item3f380ad024:g:VxIAAOSwuTxWBTW4

One problem with these devices is they do not monitor battery terminal voltage The car system voltage at the cigar lighter could be 0.5v (or more) different to the battery, depending on the various electrical loads. But at least it does give some idea of what is happening, and will show trends or changes.

 

[stephenusername]

Hi Peter,

Thanks for your advise. I will look into the monitor

Stephen

 

[jeebowhite]

Bosch S range are Silver Calcium, but have differing CCA's and capacities.

[Kim tagawa]

My car is ford fiesta st 2007 I have changed alternator new battery checked wiring but still brings the battery light on dash board hence saying is over charging ,what  could be the problemo

[Tdci-Peter]

18 hours ago, Kim tagawa said:

I have changed alternator new battery checked wiring but still brings the battery light on dash board

Since you have changed or checked everything apart from the ECU, you need to double or treble check wiring and alternator type, before you are left with just the ECU.

Using Forscan or another really comprehensive Ford specific diagnostic system to read the error code(s) that will undoubtedly be present if the light is on, might reveal a clue. I am not altogether optimistic that it will solve the problem, but it might just narrow it down.

Ensure the new alternator is the right type. There are variants, and they do get mixed up sometimes.

Looking for intermittent or poor connections in wiring takes a lot more work than a quick look or multimeter check. Wires can fail inside the insulation, this usually shows as a slightly weak or bendy bit in the wire, but when bound in a harness this is very hard to locate. In the heavy earth & power cables, looking for voltage drops from one end to the other while the alternator is delivering current is a good check. (Don't forget the big engine earth cable!)

Monitoring system voltage and voltage drops with various loads (from minimum to everything on) and at various rpm can help, though it can also be quite confusing, especially with smart charge & the ECU starts altering the voltage. Repeating these tests & looking for any inconsistent results may give a clue.

The smart charge connector on the alternator may be one wire (LIN bus) or 3 wire (older smart charge). Following these wires through to the ECU might find a break in one, or a bad connection.

Sadly, there may be no easy fix. I have spent many, many hours hunting down bad wiring in my career, and it is not much fun, but can be worth it when the system starts working again!

[laserhalen]

hi.

I know this is an old post but i have a very similar problem. S Max 2.0 diesel is overcharging after a new alternator and battery.

I have posted here (below) but not much headway just yet. at the time i originally posted it was not charging, and now after battery replacement it is over charging.

Could it be the BMS on the battery? as mentioned in the post below the alternator is getting hot after less than a minute of running, the car is slightly hunting at idle and the interior lights flicker / fluctuate when you rev the car from idle.

i measure from 15.2 to 16.1v at the battery at idle.

any help or advice would be really appreciated!

thanks. 

 

SMax Errors 230328.txt

[unofix]

Disconnect the smart charge plug from the alternator. The charging voltage measured at the battery should then be 13.6V

What voltage do you get with the smart charge plug disconnected ?

[laserhalen]

i've done that before and was baffled to see the same too high voltage, i thought there might have been some "memory" function in the alternator retaining the settings from when it had previously run. (i have no idea how the internals of the alternator work)

Anyway per your advice I did it again there now. Traces are attached. also reading with a mm at the battery shows 15.8 to 16.0. I revved slightly in that trace and it seemed the intermittent load on the alternator was more pronounced than it had been.

Thanks.

[unofix]

Thanks for the info above.

Firstly I can confirm that the alternator output with the smart connector disconnected is far too high. It should have defaulted to 13.6V +/- 0.1V

There is an unusual amount of noise on the traces. This generally indicates one of two problems. Either there is an earth fault and that the connection of the earth bond of the engine and that of the main chassis earth has a high resistance. Or the alternator has an internal fault with the rectifier pack and one of the diodes (there are 6) has gone short-circuit causing partial AC to bleed over on to the DC side.

With the engine off, use a multimeter and measure the resistance between the metal body of the alternator and the negative battery terminal. It should be no more than 0.5 ohm. In an ideal world it should be 0.1 ohm max.

If the resistance between the alternator body and the battery negative terminal exceeds the limits above check for damaged or missing earth straps. Check for rust or corrosion of the main battery negative lead and the connection to the chassis.

[laserhalen]

Thanks for that info. I'm only seeing this now I'll make the checks tomorrow. I already checked the earth points, at least the ones I could find. (2x banks of 5 in the area under the passenger side headlight.) I undid them ground them clean and refit. Only one of them had signs of corrosion, or the green onset of it. I also checked the earth on the gearbox, i understood that to be the main earth for the engine? With all of those my checks were visual or just undo and refit...I checked continuity but never checked the resistance.

One thing I thought of today - when I originally fit the alternator I undid the engine mounting on the drivers side to push the engine back slightly to allow the alternator to fit out. These are 2x m12 bolts threaded into the chassis leg. When I was putting it all back I was unable to fit the rear one. I thought I had cross threaded it, though I've prided myself on having never done this in my life and it looked straight It was possible. Today I checked the bolt it goes in 6 or 7 threads and makes a harsh stop, not sure if it had bottomed out or was simply crossed. If it was the former I wondered if I was missing an earth point in this location but I can't find any loose eyelet. But it could be by itself an earth point?

Anyway thanks again ill try your suggestions tomorrow.

[laserhalen]

@unofix I only got to check that this evening. i got 2.5ohms between alternator body and battery negative. when i measured between the alternator and some of the chassis points i got between 0.8 and 0.0.

i'm using a Metrix MX355 multimeter, (just that maybe noteworthy to you as its not an automotive mm) and i don't know how accurate it is. it still gives the "continuity beep" at 2.5ohms.

when checking at the earth point on the transmission and the ones on the chassis at some i was getting 0.5 - 0.8 then at others it would start at 0.8 and over 2 or 3 seconds reduce to 0.0.

but between alternator and -ve on the battery it was consistently 2.5.

tomorrow i will have access to an automotive multimeter, if my readings are confirmed then i have an earth problem (no s**t says you!) i will try to trace it.

as i mentioned in the other thread i was advised to check the earth on the power steering control module but i didn't find that.

Thanks again for any advice.

[unofix]

1 hour ago, laserhalen said:

tomorrow i will have access to an automotive multimeter, if my readings are confirmed then i have an earth problem (no s**t says you!) i will try to trace it.

There is a possibility that I may have unfortunately over looked something !!

In the negative lead going to the battery is there a BMS sensor on your car ?

If there is then you will need to repeat the test but with the meter connected to the BMS on the side that is NOT connected to the battery terminal. The 2.5 ohms could just be the resistance of the BMS.

 

[laserhalen]

ahh, yes there is. i think i checked it direct to the pole the last time.

i checked it again just now and i have hard to follow readings, at first 4.5, then 1.4 - 1.5 and finally right at the BMS "out" leg 0.8. it seems to vary or dwindle down the longer i held it but it didnt go below 0.8. 

ill check tomorrow with another meter just in case the metrix is not so accurate.

thanks.

[unofix]

mmmm...........

There is always the slight possibility that the BMS sensor has a fault. They are just a big shunt resistor and measure the volt drop across it which can be converted and used to calculate current flow.

I've never know a faulty one but I suppose it could happen. It would also be worth checking that the connections on both sides of the BMS are good.

[laserhalen]

ill have a look in this area tomorrow / sat. i'm trying to think is there another relevant car within reach that i could check to see what it should be.

i used a NOCO G7200 overnight on 2 separate occasions when the car first gave trouble with this issue. this was before i changed the alternator and battery. i cannot remember which side of the BMS i attached the plug to...

[laserhalen]

i'm not getting consistent resistance readings from this but the best i got was 3.4 3.5ohms at battery terminal direct and 2.5 from the other side of the BMS (cable going direct to the chassis)

i found the three earth points on the drivers side chassis leg and cleaned all three, none showed signs of corrosion really except a little on the head of the stud.

Checked the connections on the power steering pump, they were perfectly clean.

so at this point i have done the following:

• New alternator. started the car and ran idle for 20 mins, when i looked back into the car everything was dead. 
• Had alternator checked by the the supplier and they returned it said it was ok. 
• 2 weeks after the above, I fitted new battery. Thought the issue was fixed, had two short drives in the car before the "overvoltage" warning came on.
• Cleaned and reseated 10 earth points to the chassis
• Cleaned and reseated the earth point to the gearbox
• Checked continuity between pin 37 on the ECU (i forget the pin number) and the alternator (LIN Bus signal to alternator)
• Bypassed the above wire.
• Tried to reset the BMS - i used the method where you press rear fog light switch x5 and emergency x3 but my dash battery light only flashes twice after that and a few seconds later the whole dash goes dead/black for 10 seconds before coming alive again and the yellow "low battery" message appears. (is this referring to the key battery or the car battery?)
• There is/was no option to do this for me in ForScan.
• Checked both with and without the LINbus wire to the alternator. both result in overvoltage but i felt like it did it sooner with the wire connected.

just in the interest of full disclosure in case it points to anything; i charged the battery overnight while in the car as mentioned in the previous post. i did this 3 times max maybe only 2 but once with the old alternator and once after replacing it. i didn't do this with the new battery installed obviously and also not since new alternator was returned from supplier confirmed ok. but could this have damaged something?

I did not reset the bms after i changed the battery, at the time i didn't know i had to. the battery i installed is the exact same as the one i took out. Varta F17 80Ah 740A. recommended by the motor factors.

I've noticed today that if i run the engine the dash / radio everything goes completely off not long after the car starts. once or twice the car has concked out after starting. the hunting at idle is more obvious now it seems. and one time i ran it without the LIN wire connected and while it was running I connected it causing a firm load on the engine for a few seconds.

if you rev the car to e.g. 2000 the footwell lights go dim - bright - dim - bright at about 1hz. the daytime running lights (?) at the bottom of the front bumper also flicker.

Still the voltage at the battery is 16++

any ideas?!!

thanks!

[unofix]

While I'm thinking about this 🤔 here is a link to the full Ford wiring schematics for your car. They are on my own Google drive and i have limited space so can only leave them there for a few days. Download asap 😀

S-Max 2013 schematics:

https://drive.google.com/file/d/1N-8lEMGMjmMMDkERSHuMddrUv2CbDfqB/view?usp=sharing

[unofix]

Sherlock Holmes - Sir Arthur Conan Doyle When you have eliminated the impossible, whatever remains, however improbable, must be the truth.

I hate to say this, but everything is pointing to the alternator and the voltage regulator.

When you take a look at the circuit diagram for the charging circuit, it is very straight forward. There are only two wires from the alternator, the main +B cable and the Lin control. Since the alternator does not default to 13.6V with the control disconnected and you have checked and tested all earths then there is nothing else left.

[laserhalen]

yes i often quote that to myself!!

Thanks for the files, they say Fiesta though?, i guess they are the same? just on your screenshots it says SMax. I had previously bought something from EasyManuals, - VM of ford ETIS which has wiring in there but its hard to follow. what are you using, mind me asking because yours look easier / clearer.

Before I pull the trigger on a new alternator, i checked this morning its €390 for a Valeo (OEM apparently), could I ask why I don't have the option to reset the BMS in forscan and also why when i try it using the foglight method it doesn't work properly? just wondering is there something in that.

After trying the reset BMS and re-connecting the LIN the car behaves differently i.e. the whole system goes dead after running for a few mins.