Hi all I have a mk3 Ford focus 2012 titanium with start stop hill assist I have had to replace my battery 2x with 730cc 75amp start stop but nothing works when I turn on my a/c my engine judders more also at night I put my lights on car judders I reset my bms with forscan starts charging at 14.4 and slowly reduces to what it is now on load at 12.5 would it be my bms system playing up and needs replacing as it’s causing my abs and tyre sensor not to work or charge properly my cruse controll hill start and my stop start system also get tyre pressure malfunction as well any help be appreciated as been trying to sort it for 2 months now 😢

1 minute ago, Antony stoner mk3 focus said:

Hi all I have a mk3 Ford focus 2012 titanium with start stop hill assist I have had to replace my battery 2x with 730cc 75amp start stop but nothing works when I turn on my a/c my engine judders more also at night I put my lights on car judders I reset my bms with forscan starts charging at 14.4 and slowly reduces to what it is now on load at 12.5 would it be my bms system playing up and needs replacing as it’s causing my abs and tyre sensor not to work or charge properly my cruse controll hill start and my stop start system also get tyre pressure malfunction as well any help be appreciated as been trying to sort it for 2 months now 😢

Also my clutch sensor not working I even replaced with new one from ford please help it’s a project car saving it from scrap yard 

Firstly you need to forget all about Start/Stop and accept the fact it doesn't work. So that's one problem off your list.

Don't ever reset the BMS unless you have fitted a new battery.

Using a multimeter what is the battery terminal voltage approx one hour after it has been parked ?

With the engine running at a fast idle and the A/C on, what is the battery terminal voltage ?

33 minutes ago, unofix said:

Firstly you need to forget all about Start/Stop and accept the fact it doesn't work. So that's one problem off your list.

Don't ever reset the BMS unless you have fitted a new battery.

Using a multimeter what is the battery terminal voltage approx one hour after it has been parked ?

With the engine running at a fast idle and the A/C on, what is the battery terminal voltage ?

On idle it’s 12.3 after leaving it’s 12.3 with lights and ac on its 12 when car is off it’s 11.6 and I only reset bums when I put new battery in on both occasions but ac makes car judder all lights on makes it judder but turn off car is idle fine I even put a new alternator on at Ford so now I have traction light on with pressure sensor malfunction etc etc 

39 minutes ago, Antony stoner mk3 focus said:

Hi all I have a mk3 Ford focus 2012 titanium with start stop hill assist I have had to replace my battery 2x with 730cc 75amp start stop but nothing works when I turn on my a/c my engine judders more also at night I put my lights on car judders I reset my bms with forscan starts charging at 14.4 and slowly reduces to what it is now on load at 12.5 would it be my bms system playing up and needs replacing as it’s causing my abs and tyre sensor not to work or charge properly my cruse controll hill start and my stop start system also get tyre pressure malfunction as well any help be appreciated as been trying to sort it for 2 months now 😢

Also my clutch sensor not working I even replaced with new one from ford please help it’s a project car saving it from scrap yard 

 

On idle it’s 12.3 after leaving it’s 12.3 with lights and ac on its 12 when car is off it’s 11.6 and I only reset bums when I put new battery in on both occasions but ac makes car judder all lights on makes it judder but turn off car is idle fine I even put a new alternator on at Ford so now I have traction light on with pressure sensor malfunction etc etc 

 

Only thing I can think of is the bms isn’t picking up it’s a new battery and thinking it’s a old one that’s why things are starting not to work or not work properly like my ac and lights making car judder like it’s lack of power 

Your battery voltage is way too low.

You have a charging fault assuming that your battery is healthy.

Unplug the small 'smart' charge plug from your alternator and the voltage should go up to 13.95V which is the emergency default charge voltage when smart charge is not working.

 

31 minutes ago, unofix said:

Your battery voltage is way too low.

You have a charging fault assuming that your battery is healthy.

Unplug the small 'smart' charge plug from your alternator and the voltage should go up to 13.95V which is the emergency default charge voltage when smart charge is not working.

 

it’s a new alternator from Ford surly it can’t be that that’s what lead me to the BMs  on the negative battery lead 

1 hour ago, unofix said:

Firstly you need to forget all about Start/Stop and accept the fact it doesn't work. So that's one problem off your list.

Don't ever reset the BMS unless you have fitted a new battery.

Using a multimeter what is the battery terminal voltage approx one hour after it has been parked ?

With the engine running at a fast idle and the A/C on, what is the battery terminal voltage ?

On idle it’s 12.3 after leaving it’s 12.3 with lights and ac on its 12 when car is off it’s 11.6 and I only reset bums when I put new battery in on both occasions but ac makes car judder all lights on makes it judder but turn off car is idle fine I even put a new alternator on at Ford so now I have traction light on with pressure sensor malfunction etc etc 

1 hour ago, Antony stoner mk3 focus said:

Hi all I have a mk3 Ford focus 2012 titanium with start stop hill assist I have had to replace my battery 2x with 730cc 75amp start stop but nothing works when I turn on my a/c my engine judders more also at night I put my lights on car judders I reset my bms with forscan starts charging at 14.4 and slowly reduces to what it is now on load at 12.5 would it be my bms system playing up and needs replacing as it’s causing my abs and tyre sensor not to work or charge properly my cruse controll hill start and my stop start system also get tyre pressure malfunction as well any help be appreciated as been trying to sort it for 2 months now 😢

Also my clutch sensor not working I even replaced with new one from ford please help it’s a project car saving it from scrap yard 

35 minutes ago, Antony stoner mk3 focus said:

it’s a new alternator from Ford surly it can’t be that that’s what lead me to the BMs  on the negative battery lead 

Did I say you had an alternator fault ?

What I said was that you have a charging fault. So to establish if the alternator can operate correctly without the smart charge you need to first disconnect it and then measure the terminal voltage at the battery.

2 hours ago, Antony stoner mk3 focus said:

Hi all I have a mk3 Ford focus 2012 titanium with start stop hill assist I have had to replace my battery 2x with 730cc 75amp start stop but nothing works when I turn on my a/c my engine judders more also at night I put my lights on car judders I reset my bms with forscan starts charging at 14.4 and slowly reduces to what it is now on load at 12.5 would it be my bms system playing up and needs replacing as it’s causing my abs and tyre sensor not to work or charge properly my cruse controll hill start and my stop start system also get tyre pressure malfunction as well any help be appreciated as been trying to sort it for 2 months now 😢

 

9 minutes ago, unofix said:

Did I say you had an alternator fault ?

What I said was that you have a charging fault. So to establish if the alternator can operate correctly without the smart charge you need to first disconnect it and then measure the terminal voltage at the battery.

Where do I find the smart charge plug is it next to the battery case 

1 hour ago, unofix said:

Unplug the small 'smart' charge plug from your alternator

 

10 minutes ago, unofix said:

 

I don’t have a battery light on or anything tho and is it easy to get to from the top of the car to unplug it 

14 minutes ago, unofix said:

 

I don’t have a battery light on or anything tho and is it easy to get to from the top of the car to unplug it also when I unplug it and it charges better does that mean the wireing is damaged between alternator and battery