Ford Mondeo - Why does CTEK charger increase voltage to 14.4v?

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Thu 20 Aug 2015 20:19
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - Meatballs

Hi,

I recently purchased a CTEK trickle charger to keep the battery in my Mondeo topped up, as I am often away for a few days at a time.

As I understand it, the charger increases the voltage of the battery to 14.4v and then allows to voltage to drop to 12.95v before a "pulse" charge increases it 13.05v, followed by a drop to 12.95v and then another pulse, etc, etc.

Why would the charger increase the voltage to 14.4v on the initial charge?

As a new charging program starts every time I disconnect and reconnect the charger, does that mean that it charges to 14.4v every time it is reconnected? If so, should I put it on charge only when I know that I won't be using the car for a few days?

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Thu 20 Aug 2015 20:25
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - skidpan

I know nothing about CTEK chargers other than they have an excellent reputation.

What I do know, in "normal" cars alternators charge at 14.4 volts when a battery needs topping up which drops to about 14.1 or 14.2 volts in normal running with no famcy consumers switched on.

So based on that 14.4 volts after turning the charger on is perfectly normal.

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Thu 20 Aug 2015 20:32
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - Wackyracer

The Ctek chargers (or any car battery charger for that matter) do not increase the battery's voltage above what is the normal charged voltage (approx 12.7 Volts).

To charge a battery you need to have a forward voltage that is greater than the battery's normal working voltage, if there was no forward voltage then there would be no current flow from the charger to the battery and charging would not occur.

As you can see the forward voltage is the chargers output voltage minus the battery's voltage which is approx 2 volts.

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Thu 20 Aug 2015 20:49
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - RT

That's sounds exactly how all smart chargers work - if the battery is 100% fully charged at the point of switch-on, the 14.4v only lasts a very short time - the charger needs to do this to determine it's charging pattern.

Incidentaly, 14.4v is a standard charging voltage and car alternators run at that all the time, or at least they did as many models now have smart alternators.

The CTEK is very well regarded - I have one which has kept one of my batteries in good shape for 20 years.

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Thu 20 Aug 2015 20:54
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - elekie&a/c doctor

All relevent info here.But just as a sidestep,why would you need to charge a battery when a car is left unused for a few days??I run a Mondeo that gets used very irregularly (sometimes left for 2 months)and never have a problem with a flat battery.Btw Ford smart charge systems can run upto 15.8 volts when required.

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Fri 21 Aug 2015 13:16
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - Meatballs

I did manage to flatten it recently (which is why I bought the charger). Only used very intermittantly for 3 months and then only one short trip in a 4 week period, and it was flat.

The battery is 72Ah so, assuming a background drain of 50mA, I suppose I would expect it to go from fully charged to flat in about 60 days.

Having had a look at the manual it seems that the float voltage is actually 13.4v (the charger does run at 14.4v during the main charging) but then floats at 13.4v.

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Fri 21 Aug 2015 00:50
Ford Mondeo - Why does CTEK charger increase voltage to 14.4v? - Manatee

There are three basic phases for a smart charger.

They start with constant current (at the charger rating) which means the voltage starts low and rises to c. 14.4V. The voltage remains there as the battery continues to charge and the current drops. When current has dropped to a trickle the charger goes into pulse or maintenance mode. It's this last phase that means you can leave it connected.

Some will do a pulsing phase to start with which is associated with desulphation.

You should be able to leave it connected. I have one on a fair-weather car that isn't used regularly, does short journeys and has a small battery just for good measure (it's an old MX5 with a c. 30Ah gel battery). I'd say the battery is performing better now than it was when I bought the car in 2011... not sure how that works!

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