[Lorian]

By accident today I selected the volts display on my scangauge before driving off. I was suprised to see it illustrated really well the bosch active battery management. This feature (not on all cars) charges the battery more when decelerating and less when accelerating, to help fuel economy a little.

This table illustrates what I saw. Thre more you accelerate the lower the voltage seen. The more you use the engine to decelerate the higher the voltage, within these bounds. When maintaining speed it stays at 14.1v constantly.

[2i30s]

I'm going to check my scangauge charge figures. 

[Shambles]

Sounds like the system installed in the Prius, where it charges during decel, but with the Prius it has to be selected manually.

Good spot, but you should be keeping your eyes on the road

[Lorian]

Plenty of time when driving in the snow ;-)

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[Lorian]

Forgot to say as soon as you switch the headlights on this facility switches off.

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Forgot to say as soon as you switch the headlights on this facility switches off.

Ah, that sounds right... I wondered what such a high voltage would do to the lights.

[Lorian]

I think the voltage the scangauge is reporting is before regulation, ie what is used to charge the battery. I,m sure all the systems that require a regulated output get such. For example the internal lights and dash lights dont get brighter and dimmer.

I think you can tell if your i30 has this by checking if you have the temperature sensor on one of the the battery terminals

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[agentr31]

hrmm... any pics of said sensor please... i could pull out my turbo timer and watch the volts... somewhere in its menu is a voltage gauge... god only knows why...

[Lorian]

I can't even open the bonnet at the moment, it is covered in snow. It's a little copper and siver thing attached directly to the right hand battery terminal. I suspect it's only been on cars since MY2009.5 and maybe just european ones.

I also notice yesterday when they car has just started and it's really cold (presumably the battery is cold according to the battery thermometer) it pegs the voltage at 14.6V until things have warmed up.

Quite a clever little system.