We have had the garbage "Low Battery" alert at various times since new (always worse in Winter) which we simply ignore.

The car thinks the battery is only charged to 54% whilst the battery condition meter I have always gives more.

The current (pun!) battery is down to 30% of it's design rating so trying to get it to charge more before replacing (I know this is low and not covered, despite a "5 year warranty" and it is 4 years old)

I can't find Battery Target State of Charge in the BCM (after SBL is loaded (BG9T-14C097-AA.vbf)

The only battery related PIDs I can find are:

Battery: No rear battery

Battery Saver Time: Not configured

Battery: T7 80Ah 700 CCA

Battery Monitor Sensor: With battery monitor sensor.

Does that mean the state of charge isn't adjustable on a 2011 model or am I missing something?

 

21 hours ago, Shearers said:

Does that mean the state of charge isn't adjustable on a 2011 model or am I missing something?

I'll quickly answer the SOC question and say that it is not adjustable on a 2011 model. In fact it only seems to have become adjustable from around 2018.

Your car does not use the infamous Smart Charge system that is used on more modern Ford's and so no need for the SOC to be adjusted.

As regards your battery test meter, you are only going to get an accurate reading using a digital multimeter. To get a reliable reading wait at least 1 hour after parking up. Unlock the car and open the bonnet and then leave the car untouched for twenty minutes. Measure the battery terminal voltage and compare to the chart below.

If your battery is more than 4 years old then sadly it is living on borrowed time by current day standards. Always replace with the largest capacity battery that you can physically fit in to your battery tray, typically the battery used for those with a diesel engine.

Are you sure that your 2011 car actually has a BMS sensor fitted in the negative battery lead ? Most models didn't start to get them fitted until 2013.

Thanks both for the above.

The negative lead does appears to have a sensor (lying at bottom of picture but not that clear) and, as mentioned there is a PID (?) "With battery Monitor Sensor" and my ancient ETIS manual states it has the Smart Charging system - Ford works in mysterious ways?
However, if there's no adjustment option, then that's the way it seems to be.
We are very unlucky with batteries and I share the "always living on borrowed time with them" mantra but suppose the Yuasa 80Ah 5 yr warranty we have had for 4 years has done quite well.
I have also realised that Yuasa only "warrant" their batteries for manufacturing defects for 1 year and it is up to resellers to add to that, or not and, even if they do, it may again, only be for manufacturing defects and not for capacity loss (which is the major normal failure mode)

I use both a multimeter and battery tester (giving Volts, CCA, internal resistance, % charge etc) but like all things battery related, a pinch of salt is necessary?

I rate: https://batteryuniversity.com/ for info and they seem to emphasise that batteries, like humans, have multiple failure modes so measuring one parameter isn't enough to make a decision on expected life and capacity is very difficult to measure without an actual discharge test which I've done.

The coming cold snap may well make the decision to change for me rather than relying on it to run to it's warranted period. Dealers will be stocking up as I type 😉!

Thanks again!

 

There's a bit of confusion around terminology here.

Fords have had SmartCharge since the early 2000's.  It's a basic system that just charges a cold battery more before it warms up.

From around 2010, variable rate charging was added to most models.  This tries to charge on over-run as much as possible and the charge rate is dependent on the level of battery charge.

From around 2018 the emissions regs became even tighter and that is the point where the battery is only charged up to 80% as standard.  There isn't a specific name for that though, hence the issues with terminology.

1 hour ago, Shearers said:

The negative lead does appears to have a sensor (lying at bottom of picture but not that clear)

Yes indeed, I confirm that is a BMS so your car must be one of the first to have been fitted with one.

1 hour ago, Shearers said:

ETIS manual states it has the Smart Charging system

Kind of already answered by Tom in his post above. Over the last 14 or so years Ford have had 3 different charging systems that I know of. Just to confuse everyone they are all refereed to as "Smart Charging" but only the latest version which I will call "generation 3" (no pun was intended) has the ability for the SOC to be adjusted.

1 hour ago, Shearers said:

also realised that Yuasa only "warrant" their batteries for manufacturing defects for 1 year and it is up to resellers to add to that, or not and, even if they do, it may again, only be for manufacturing defects and not for capacity loss

  Finally, I'll just add that I had a Yuasa battery replaced free of charge in it's third year of service by Halfords. Just shows sometimes things like a warranty do work. 👍

6 hours ago, TomsFocus said:

From around 2018 the emissions regs became even tighter and that is the point where the battery is only charged up to 80% as standard.  There isn't a specific name for that though, hence the issues with terminology.

Some of us do have a specific name for it, but it's too rude to post here!😀

Thanks for all of that explanation which now makes sense, along with the rude name I'd probably also use!

The plot has thickened in that I have noticed that the connection at the battery that goes to the main fuse box has been getting hot (as evidenced by the melted plastic inside the battery cover - it has happened after the photo above) so the lug at the battery needs replacing and a new joint made further down which I'm proposing to get the gear and crimp the fittings.
I don't think this negates the battery capacity issue but it is certainly likely to be a point of failure.
If the battery does fail, I'll be straight down to Halfords (where I bought it from)  so thanks for that hint @unofix