12v Battery

[Mick Evans]

Hi all. Yesterday i got in my MG5 and started the car. 12v battery showed 12.5v
I thought when you put the car on charge it also charged the 12v battery?
Am I wrong or do i have a problem.
I have got a trickle charger on it at the minute.
TIA

 

[Alb]

Do you mean you put the car in READY mode and it was only reading 12.5V?
If so, you have a fault.

 

[Jomarkh]

Hi all. Yesterday i got in my MG5 and started the car. 12v battery showed 12.5v
I thought when you put the car on charge it also charged the 12v battery?
Am I wrong or do i have a problem.
I have got a trickle charger on it at the minute.
TIA

It should be about 14V in 'ready' mode but will show 12v+ in stby mode.

 

[JohnV6]

Batteries are charged by around 14 V usually. 12.5V is fine for a battery not being used or charged.
On my ZS EV you can using the ismart app see the voltage fall to 12.5V then the drive battery recharges it.

the usual advice re voltages is if it reads 11.9 volts it is only 20% efficient

12.12v 40% efficient

12.3 volts 60% efficient

12.52 volts 80% efficient

12.72 volts 100% efficient