[veeeight]

@SweepieW176 the OP may be asking about the HV battery pack in his hybrid car, as opposed to the 12V starter battery

In any case - sorry to disagree with you - but using a voltmeter will only give an indication of the SOC of the battery (and maybe if a cell is down) - not the SOH of a battery.

if you really have nothing better to do and the alternative is sticking matchsticks in your eyes - have a read of the thread below, it will explain why a simple “voltmeter test” does not apply to “modern” cars with EU6 “smart alternator” technology ……

https://www.aclassclub.co.uk/threads/eu6-smart-alternator-charging.23533/

(TLDR: Many owners are getting “partially charged” messages, despite their batteries reading a healthy >12.5V, but due to deteriorating SOH, the capacity of the battery is below optimum).

12V Battery Warnings

Getting the alert on Mercedes Me that my battery is low, probably because I haven’t been out on a long trip for a couple of weeks Did a short one and noticed stop/start was working Guess it is a case of too much information

www.aclassclub.co.uk

 

[veeeight]

Hi spot on, the Hybrid battery pack, how do i check it's health?

Unfortunately you need diagnostics, to get the SOH information.

The diagnostics will interrogate the BMS, and perform a discharge test (simulated) the HV battery.

I wouldn’t take any dashboard display readings as gospel, they have been known to display porkie pies …….