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Chrisj-mk5

Battery not fully charged

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Hi to everyone out there..I wonder if anyone can help I had my car serviced at my local ford dealership when I got it back they said that they had tested the battery then they said it was only about half charged..before I took it to garage my stop/start system stopped working they said it was cause the battery wasn't fully charged..I'm not a mechanic so I have to take there word..I've took the car on several long runs but still no joy also cause of the lack juice in battery(car still starts ok) my quick clear windscreen doesn't work..my question is does anybody out there have any ideas/solutions for me...look forward to replays thanks

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Do you do lots of short journeys which are draining the battery?

We bought a trickle charger for my mum after the dealer wanted £25 to charge her battery, left it on overnight and stop start was working again after that.

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14 hours ago, Chrisj-mk5 said:

I've took the car on several long runs but still no joy also cause of the lack juice in battery(car still starts ok) my quick clear windscreen doesn't work.

There is no way to reliably determine the charge level in an older battery without doing a set of full charge & discharge cycles, which would take a long time (days), and stress the battery. The 50% charge reading could be because the battery is fine, but it is not being charged properly, or it could be the battery is failing, and can only hold 50% of its nominal charge.

So it could the the charging system, or the battery. As the batteries in these stop-start cars are usually very expensive, the usual route of just replacing the battery first is not very attractive.

Monitoring the charge voltage while the car is in use is one option. You can get plug-in voltmeters that fit in the cigar socket very cheap. But I would cross check its readings using a decent multimeter on the battery terminals before relying on it. On some cars you can get battery volts on the dash, but the same need to cross check it still very much applies. Do not trust it unless checked!

You should expect to see over 14.2v (up to 14.8v) at times while driving. This is the voltage a battery needs to reach full charge. On long drives, or when hot, or under heavy load like screen heaters, the voltage may drop a bit (into the 13s). When left overnight, the battery should hold at 12.5v ish (though door unlocking & interior light will pull it down a bit).

The charging system on these modern stop-start cars is rather complex, it is not just an alternator. There are also things like a BMS (battery monitoring sensor, mounted on the battery -ver terminal) that can go wrong. But if the car does put out the needed voltage (over 14v) for a reasonable amount of time, but the battery still records 50% charge, then the battery is duff. Otherwise the charge system may need investigation.

Charging the battery using a good, regulated charger for at least 12 hours is another route, If this does not get it to full charge, then again, the battery is duff.

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On Monday January 23, 2017 at 10:38 AM, Chrisj-mk5 said:

Hi to everyone out there..I wonder if anyone can help I had my car serviced at my local ford dealership when I got it back they said that they had tested the battery then they said it was only about half charged..before I took it to garage my stop/start system stopped working they said it was cause the battery wasn't fully charged..I'm not a mechanic so I have to take there word..I've took the car on several long runs but still no joy also cause of the lack juice in battery(car still starts ok) my quick clear windscreen doesn't work..my question is does anybody out there have any ideas/solutions for me...look forward to replays thanks

You need access to a DVM. Beg, steal, borrow or buy. You don't have to be a mechanic, but you may have to tell us which engine and model of car you have.
 

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Some people love stop/start and some don’t. I’m one that don’t like them. All parts got a life span. Let’s say a battery will do 370 thousand stop/starts. Fred got stop/start turned on and Tom got stop/start turned off. Both did same runs each week to shops and run into traffic. Fred car started 10 time where has Tom started once. Who do you think will get to 370 thousand first. If you turn off stop/start your battery’ Starter’ starter ring will last much longer.

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I don’t like stop start. I always turn mine off whenever I remember. Wish I could turn it off permanently. I think if people understood exactly how everything works and had dismantled these parts and seen what wear occurs a lot more people might turn it off to conserve the mechanical parts

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