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Mk 8 battery monitoring reset


jsk
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That's about right. The BMS is actually a fairly sophisticated Coulomb counter, another of the systems being trialled for electric vehicles. It allows the battery to be charged rather differently to the old 14.4 constant voltage by measuring the energy drawn and then managing the optimum rate of replacement. A big battery with an honest 12Volts will start the engine and the alternator isn't always connected because fuel saving is all about reducing unnecessary energy use  The physics and chemistry of modern battery management is quite a science. When you consider that alternators were considered to be a revolutionary advance on late 60s Vauxhalls and Ford were making six volt cars as recently as 1961, it is high time. The stereo system in my car consumes many times what it used to and the heated windscreen, power windows, locks and engine steering and traction control all use Watts. Lots of them.  which is why the alternator can deliver 150 Amps and not 35 as was. Bearing that in mind, the battery does rather well compared to those of twenty years ago.

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I have 2019 focus my stop start never works I go for a 2 hour drive still doesn’t work only way to get it to work is to fully recharge the battery then it only works for one day tried resetting the bms still the same I’ve got in at the dealership on Monday so see what they have to say

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14 minutes ago, DaveG1975 said:

only way to get it to work is to fully recharge the battery then it only works for one day tried resetting the bms still the same

Maybe we could do a swap, mine insists on working once per journey before it gets turned off ?

I increased the battery SOC to 95% (kept a little back for latter 😉) beause I was getting problems with the keyless entry not being available on all four doors, and the auto hold turning itself off from time time (it should at least give a warning that it has turned itself off), which catches you out when driving an automatic.

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I often find the S/S won't work during a long run but as I've said before I do think that the system stores the energy and release to the battery gradually which is reliant on " Key cycles" ie stopping the engine locking the car and restarting. Seem to find a day or so after the long run the S/S begins to work until normal practice is resumed.

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This is a very intresting video for all those who would like to know why their Stop/Start system doesn't work. Just looking a the video and doing a very rough count it seems that there is over 110 sensors/items/conditions that have to be "Just Right" before the system will operate.

 

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Sheer bulldung. The system is fine and optional. Those of us who live in crowded towns appreciate the quiet and the fact that when we are stationary it doesn't turn the car into a pollution machine. Bombarding us all with scare stories is just not helpful. Why do you think that so many people actually want it to work?

Explaining how it works, what you should expect of it and how to keep it healthy would be a better use of your time than blind trolling.

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1 hour ago, unofix said:

This is a very intresting video for all those who would like to know why their Stop/Start system doesn't work. Just looking a the video and doing a very rough count it seems that there is over 110 sensors/items/conditions that have to be "Just Right" before the system will operate.

 

Interesting video. For info the minimum SOC for my Petrol model is 69% before S/S works, might be different for a Diesel.

As well as the other reasons, there also needs to be a certain amount of fuel in the tank for it to work, which speaks volumes for anyone who thinks they are saving fuel🤣, for anyone who does not get this bit, think about it.

Interesting that he reset the BCM and not the BMS. I have seen people saying that you should reset the BMS, which goes against what Ford say. The BMS should only be reset when a new battery is installed.

I also roll about laughing when people say they want S/S to work for environmental reasons. Anyone who truly cares about the planet would never use any form of motorised transport.   

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No, we would all walk or ride horses and die of cholera or diphtheria. Fortunately we have evolved beyond that. Even Dorset has the horseless carriage now, despite the luddites burning the men with the red flags.  Of course we could all do everything online but you can't lay bricks with a computer, nor get them where they need to be. This is a car enthusiasts' forum and our cars are much more environmentally sensitive than they have ever been been.

Transport promotes evolution just as travel broadens the mind as speaking to somebody who has never considered having a passport will confirm. We need cars. We continue to make them as sparing on the planet as we can.

How do you plan to feed us all farming with a horse drawn plough?

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With stop/start not working I tested my battery charge with a tester which reported 92% charge. I then connected forscan where the car was reporting 62% charge. I reset the system and it immediately reported the soc as 94% charge. SS worked from the next journey and was worked faultlessly since. Why would the car be reporting an incorrect soc. Isn't the system ment to constantly test and monitor soc?

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the car believed it was only 62 percent charged and had inhibited ss due to low charge despite having just completed a long return journey, which is why i checked it. if the vehicle had been charged incorrectly the soc would of recalibrated when left switched off and locked for 8 hours plus

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Just picked my focus up tonight from the dealership fully recharged the battery last night and checked everything couldn’t fine any fault so they have reset the perimeter on the system all seems good at the moment and it’s now charging at 12.3v 

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