Overcharging - opinions please

[Ian Durrant]

Our Stag related TR7 ( ) has had three batteries in two years, At the last one I replaced the regulator because I measured 16 odd volts at the battery with the engine revving. That dropped it to 14.7 on the new regulator, but I am suspicious that the battery is deteriorating again, so I have just replaced the regulator again and the voltage is now steady at 14.3 which still seems a tad high to me. Googling reveals various opinions, that anything between 13.8 and 14.5 is good. So I thought i'd ask on the forum with more experts per square gigabyte than anywhere else on the net . Am I ok at 14.3 or do I need to investigate further?

[Andrew S]

Stupid question may be, is there a chance that the alternator pulley is a non standard size this turning at a higher rate?

[Ian Durrant]

Hi Andrew, I don't think that would cause a problem with voltage because the regulator would simply lower the field current to drop the voltage back down. I am not sure if 14.3 is too high or not, it might be perfectly ok, whenever I have had this problem before swapping the regulator cured it but maybe the available regulators now are not of the quality they used to be

[wilf]

14.3V is the expected "on charge" voltage at the battery terminals.

[GDPR]

13.6 to 14.4v is needed to successfully charge the battery, below it won't charge, over and it'll cook

[mal fitz]

Mine reading 13.9 V on tickover

[GDPR]

Seems ok to me - just got to watch the offload voltage doesn't go above 14.4v, and the voltage doesn't sag below 13.8v at around 2000rpm with the headlights on main - if it does below it could mean a high resistance in a charging or earth lead

[LAMBRETTLAD]

you tube has many good videos on how to tell if your alternator is functioning correctly ,and diagnosing any faults ,sorry don't know how to post a link on this machine ,MAC

[milothedog]

you tube has many good videos on how to tell if your alternator is functioning correctly ,and diagnosing any faults ,sorry don't know how to post a link on this machine ,MAC

Can you not just copy and paste the URL in the insert video box

[LAMBRETTLAD]

Hi when I play you tube from the app I have no url showing on the screen

If you put Testing alternators in the you tube search box ,, the plenty of choices show up

[jleyton]

Can you not just copy and paste the URL in the insert video box

My Motorola Xoom won't allow me to copy and paste anything in a Forum post - I think it is quite an early model which I won.

Cheers

Julian

[Ian Durrant]

Thanks guys, I am happy it won't cook the battery any further now.