Battery monitoring

[Sandgroper]

It is plain that our cars rely on a good and consistent battery performance. I am cosidering installing a voltmeter to give a regular review of battery/generator condition. Has anyone carried this out yet? 

 

Any hints gladly awaited.

[Liger1956]

I have a digital volt meter that plugs into the accessory socket on the centre console of my Octavia. However I do not leave it in all of the time as it will draw a small amount of current and so help to deplete the battery. Also having things like dashcam powered all the time is another draw on the available power.

 

Measuring the voltage is not the whole story as even with a good voltage an old battery can sag a lot when the full load of the starter motor is applied.

[Breezy_Pete]

I have a non-backlit LCD digital voltmeter permanently connected directly (though fused) to the battery terminals. I can also switch it so that the positive connection measures at the alternator output instead.

As said above if you want a permanent display (which is good because it can give you the most accurate resting voltage, with car fully 'asleep' and locked, viewing through a window) make sure the current draw of this measuring device is very low.  In my case the total consumption of the set-up is 0.5mA (measured), which is pretty frugal. Since it isn't backlit, I can't really see it when driving at night, but I don't do a lot of that. A  phone torch shone through drivers door window can make it visible enough pre-journey during winter.

 

 

[MartiniB]

similar to this shows almost correct values

https://www.aliexpress.com/item/33005993511.html

just +0.1v to values reported from car computer trough OBDeleven

and +0.12v to values on multi meter directly on battery's + and -

 

few winter time measures (use Google Translate)

https://www.drive2.ru/l/553005421577634100/

after which i got battery warranty replacement

https://www.briskoda.net/forums/topic/454623-what-have-you-done-to-your-superb-iii-today/?do=findComment&comment=5370984

 

Edited 23 March, 2020 by MartiniB