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453 Stop/Start & General Faults

Modification Details

So far, almost all errors I have seen appear on the dashboard LCD have actually had nothing
to do with the fault being described. For example, this is a stop/start malfunction.

Ignore what the car is telling you. Almost every single occasion, the fault is with the battery.
The rest of the page will be interspersed with various faults that are all actually a battery problem.

But I Thought The Stop/Start Battery Was Better

Yes, stop/start batteries are usually AFB/EFB or AGM type instead of the old SLA car battery types.
They are designed to start the car 3 or 4 times more than the old battery type.

SLA - 30,000 starts.
AFB/EFB 85,000 starts.
AGM 120,000 starts.

The 453 battery is an AFB (Advanced Flooded Battery) so you'd expect it to be good.
Especially considering how much more expensive they are compared to SLA batteries.

So, Why Are There So Many 453 Battery Failures?

The problem lies with what you are expecting the battery to do.
It could be required to start the car 5 times a minute in a traffic jam.

To do this, it needs the power to start the car. If the car is only running for 10 seconds,
the car has to put a lot of power into the battery as quickly as possible.

To do this, the alternator forces up to 16.5 volts into the battery.
Over voltage on the old SLA battery was a bad idea. Over voltage on an AFB type is worse.

AFB type batteries suffer very badly if over charged. They quickly lose capacity to the point that they can't fully power all
of the elctrical systems. The lack of power causes an error in that module which then brings up an error on the screen.

What's The Fix?

Step 1 is obviously to buy a new battery.
Step 2 is to turn off stop/start when ever you remember.

There is no proof that this will stop the over voltage but the car does monitor the battery voltage so,
if the stop/start isn't draining the battery, the voltage shouldn't get low and the car won't need to excessively charge it.

The next step for me is to look into the coding to see if I can reduce this 16.5 volt charging to something sensible.

Fitted A New Battery?

You'd like to think that it's as easy as fitting a new battery and that'd be it, but that may not be the case.

The car's electronics monitors the state of the battery and reduces how much power it expects to be able
to get from the battery. Just fitting a new battery doesn't tell the car that it can expect more power.

So there's a chance that the car has to be told that it has a new battery so it can reset the battery parameters.

Annoyingly, this can currently only be done with MB Star but I am looking to see if there are
any parameters in DDT4All that could be changed, although as yet I haven't seen anything.

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