New Battery / Alternator Kwik Fit

superjay

So....
In the last 2 weeks I've had a right battle on my hands. 
I had a stop / start battery fitted by Kwik Fit in November 2018. About 2 weeks ago my battery died again. (It had shown signs of coughing and spluttering in mornings in the run up) . So I got Greenflag to jump me, I drove it around as recommend for 20 mins and finished up in Kwik Fit to get them to run a battery test. They ran the test and said it was fine and it was most likely my alternator.... just as the lockdown started I priced an alternator everywhere all coming in around 500 quid.

I rang my usual mechanic (good guy, has never let me down) and he said I would be better of getting some tests done as its not forced to be the alternator. The car broke down again on the way to the garage so had to get it recovered at my own cost. He charged the battery and took it ff the car overnight. When he came back in morning it was dead..... he checked the alternator amongst other bits and said they were all running fine.

I went back to kwik fit as the battery was still under warranty.They said they would run the same test as my mechanic to confirm. Got a call this morning and they told me my battery was fine again but as a "gesture of good will" they would replace it free of charge, which I found a bit weird. 

Theyve passed me the battery test receipts one done yesterday at 3:10pm and one at 7:58am this morning. The battery health bar has dropped 50% in that 17 Hour period. I have queried with them and he said that this was normal and that as long as it didnt drop below the line its a good battery. I'm a complete idiot with cars but that didnt seem right to me? 

I've driven home and car seems fine with the new battery..... 

Question is do I do anymore diagnostics to make sure the alternator is OK or is this a suck it and see type deal?
Is the fact they fitted a brand new battery an ommision of fault without admitting it?

Im guessing I'm just hoping not to lay out 500 quid for an new alternator.

superjay

These are the battery test receipts 

daveyjp

12.48v dropping to 12.39v overnight is fine. A healthy battery should read 12.4 - 12.6.  As soon as you start the car and run it the charge will be back up to 12.5ish.

Norman_Castle

I charged my battery yesterday. This morning it was at 12.6v, its now 12.59v. Its 3+ years old and not fitted to the car.

I'd trust your reliable mechanics opinion about the alternator. Did you tell kwik fit the car needed recovering at your expense?

forgotmyname

Just because the alternator charges does not mean its 100%.  Faulty rectifier?

ElephantBoy57

A good, healthy car battery should have no fewer than 12.6 volts. The photos above it says "GOOD, RECHARGE", surely that is saying it needs to be recharged?

superjay

Norman_Castle said:

I charged my battery yesterday. This morning it was at 12.6v, its now 12.59v. Its 3+ years old and not fitted to the car.

I'd trust your reliable mechanics opinion about the alternator. Did you tell kwik fit the car needed recovering at your expense?

I did I think this is why he went the "gesture of good will" route. He said the battery is fine but he would replace it for free anyway.

I found that super weird. 

Mutton_Geoff

forgotmyname said:

Just because the alternator charges does not mean its 100%.  Faulty rectifier?

Which is integral inside the alternator. 

daveyjp

ElephantBoy57 said:

A good, healthy car battery should have no fewer than 12.6 volts. The photos above it says "GOOD, RECHARGE", surely that is saying it needs to be recharged?

The issue is people are focussing on something they never generally cared about.  Jump in start car, use car, park car and repeat.  Most users have no idea what their battery charge status is at any one time.

The battery was tested at 15.10 and then again at 07.58 the next morning, almost 17 hours powering the alarm and other ancillary devices fitted to modern vehicles.

An older car with no such features could stand for months and not lose any charge, some modern cars can barely go a couple of weeks.

This is why a small drop is therefore to be expected.  Within a few miles of driving the battery will be back to full charge.

forgotmyname

Mutton_Geoff said:

forgotmyname said:

Just because the alternator charges does not mean its 100%.  Faulty rectifier?

Which is integral inside the alternator. 

Yes and?   Your point?

Just because the alternator passes the charge test does not mean the alternator is 100%.  The rectifier could be faulty
and draining the battery. This may only happen some days and not others or at certain temperatures or even when
there is a temperature change, or even down to the moisture in the air.

Lots of ways it could pass the charge test yet actually be faulty.

droopsnoot

What does that "Battery health" bar graph actually measure? 
Interesting that the first receipt has a note about the charging system on the bottom that says "no problems".