Due to a couple of flat battery situations in the last few months. I have replaced the battery three months ago and last week the alternator. I am using a Sealey Ak500 to monitor the charging status (image below). For some reason the system will not charge the battery above 12.2v and today whilst on a 90 mile run in noticed the new alternator was charging at only 13.5v. When I got the vehicle home I checked the battery status which showed 12.2v, exactly where it was when I started the journey! A few questions from this:

1. Is the Sealey unit any good?
2. Is there a regulator between the alternator and the battery?
3. Why will the new battery and alternator not charge above 12.2v?

To add to the above the battery is losing around 0.4v overnight....

Any help gratefully received....thanks in advance

Hi

1 I assume the Sealey is just a voltage tester so should be ok
13.5v should although a bit low should charge a good Battery

2 The regulator is part of the Alternator

3 Only thing I can say is that the New Battery might be a duffer,
you said it has been flat a couple of times this can up even a newish Battery.

Losing 0,4 v points to a parasitic draw and you will need a multimeter to check your fuses
to find out where the draw is coming from.

I live in Dunoon, are you near I could check it out with you.

Max

Hi Max, any help with this will be gratefully received. I’ll send you a pm. Thank you

I only know enough to be dangerous lol.
All the voltages at different conditions seem a little low - which is why I have a suspicion you're not seeing the true voltage.
A couple of thoughts, if you're plugging the Sealey unit into a power / lighter socket it's possible you're not seeing the true voltage, every connector and connection has the potential to cause resistance, which would show a lower voltage. I'm not saying thats your problem, but the first thing I'd do is use a known trusted voltmeter directly on the battery. Does it read the same voltage as the sealey unit when it's plugged inside?
Is there a way to connect the sealey unit directly to the battery? if so do you have access to another car that you can connect it directly to the battery and see what voltages it shows? (before starting, whilst running etc)

Battery voltage can change over time depending upon temperature, 0.4v wouldn't ring alarm bells for me unless it continues to drop by another 0.4v the next day (12.4 to 12, then 12 to 11.6, then 11.6 to 11.2).

Good Luck Anything can be made to work if you fiddle with it long enough (and have deep pockets|)
Current cars, 2011 FF 4.4 TVD8; Audit TT 1.8T convertible.

Treebor99 thanks for your message. I’ve ordered a voltmeter to check at the battery terminals. Triumph72 was good enough to check the system for me yesterday and couldn’t detect any significant battery drain. Starting to wonder now if the old alternator has damaged the 3 month old battery!!

It may not be any consolation, but a short while after my alterrnator failed, just outside the dealer's warranty, (how do they do that?) my battery gave up. I wouldn't dscount yours being the same.

However, as the battery was inside its three year warranty it was exchanged by the dealer after a test at Halfrauds. I may have forgotten to tell the dealer the alternator failed.

If your battery has a good warranty, contact the supplier and ask for a replacement. Cheers
Richard

(there are no such things as an ordinary FullFat, an ordinary cat or too many tools)
2011 TDV8 Vogue Santorini Black
Gap IIDBT

Thanks rjff. Battery checked with multimeter 12.9v last night after being fully charged....12.2v this morning. I’ll fully charge the battery out of the vehicle next and see if it drops overnight.....

Is this the correct spec. battery for my vehicle?

Battery draw traced to fuse 49. Specific component still to be identified.....probably never needed a replacement battery or alternator!