What’s this then?

[Hindy500]

Investigating some electrical issues, noticed this grey tube behind the battery. Can anyone ID it?

[bigwinn]

I’ll be advised but I think it’s a breather tube to run from the battery to the outside

[colb]

Yep battery vent pipe fits to overflow nipple on the battery to route overflow and fumes from battery via the tube and out of the car through the underside. May not be used on fully sealed batteries which don't have vents.

[Zedebee]

The battery may have a little transit plug in which should be removed before fitting the vent hose. I’ve just got a new battery and it had a vent on either end.

[Hindy500]

Aha, thanks!