Battery Question

bluenose1940 · July 28, 2015

I have been trickle charging the Battery on my car and am wondering what the reading should be when it is fully charged.

Just had a look now and it is showing a reading of 12,79 volts.

Thanks in advance.

ROYT · July 28, 2015

You could check with a hydrometer if you have removable cell covers. [unlikely]

You are taking a reading with no load on the Battery, so it's difficult to say.

If it cranks the car really lively, i would say it's well charged

ColinBarber · July 28, 2015

If it cranks the car really lively, i would say it's well charged

The 12v Battery doesn't crank the engine at all on a hybrid :winky:

ROYT · July 28, 2015

Oh Heck, should have gone to Specsavers...............

bluenose1940 · July 30, 2015

If it cranks the car really lively, i would say it's well charged

The 12v Battery doesn't crank the engine at all on a hybrid :winky:

I'm lost now, if the 12v Battery doesn't crank the engine, why couldn't I start the car when the 12v Battery was flat? Remember.......I'm not very good at the techie bits!!

Still learning every day

ColinBarber · July 30, 2015

The 12v Battery is used for the standby electrics (e.g. the alarm, central locking etc) and it also is used for the 'ignition' - which initialises the hybrid system. Once the car is in the 'Ready' state the hybrid system starts generating the 12v for the car systems and it will start recharging the 12v lead acid Battery.

The petrol engine is started by the hybrid generator/motor rather than by using a traditional starter motor. This allows the engine to be turned over much faster and smoother which is why it can be difficult to even detect when the engine is being stopped/started whilst driving.

If your 12v Battery is flat then you cannot initialise the hybrid system, it cannot go into 'Ready' and it cannot start the petrol engine.

The one good thing about the hybrid system is it doesn't need a lot of power from the 12v Battery. If your main Battery is flat you can 'jump' it with just a small 12v Battery (such as a moped battery) as it only needs to provide a few amps to unlock the doors and power up the car.