there's a useful battery thread somewhere in here
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Curiouser and curiouser!
My 2008 car is on its second Banner, and neither of them was fitted with a vent pipe. I don't get any liquid leaks at all. The current battery was supplied and fitted by CC in 2014 when they did my roller-barrel upgrade, so I would have expected them to fit a vent if one was needed. The battery has an open hole at the negative end and a black plug at the positive end. The electrolyte levels are just at the top of the marker peg.
It's mentioned in several of Banner's own FAQs. They call it a "degassing hose".
And that doesn't explain why it's widely used in Sevens with the battery in the engine bay.
Thanks for that link, Jonathan.
The relevant FAQ says:
Must I use a degassing hose when the battery is installed inside the vehicle?
Yes, always! We prescribe the obligatory employment of a degassing hose (Part Number 1030001700 with a hose length of 90 cm including an elbow) when installing all types of lead-acid battery in the interior/passenger compartment.
Maybe the key phrases here are inside the vehicle and interior/passenger compartment, neither of which applies to a battery mounted in the well ventilated engine bay of a 7. So, it would appear that my lack of hose is OK after all!
If there is an open hole instead of a vent pipe, I would put the battery on the bench and tip it on end at a 45 degree or greater angle with the vent hole down. At 45 degrees, that would simulate a 1g force from braking or cornering. If the vent is properly baffled or valved inside the battery, no acid should leak out, if any leaks out it would be best to use the pipe to channel acid down on to the road instead of on to the car structure.
Non technical reply, just a word of warning.
When the weather was good I used to put a jacket in the passenger foot well of my X Flow. On one blat the regulator on the alternator failed and it fried the battery. Because I didn't have a vent pipe I no longer had a jacket or carpets.
Yes, having seen the corrosion that battery acid can do, I'd rather have a vent pipe venting below the lower chassis tubes!
Agree, it isn't uncommon to see a corroded battery tray. At £3.29 I would invest in one ;)
Well, I just messaged our local battery business about a banner vent pipe and because I bought my banner battery from them I could have one for free :-)
If anyone is ordering a new banner battery maybe ask if it comes with a vent pipe?
I thought I'd get a second opinion, so I asked Tayna. They replied:
The venting is related to the application it is fitted on and not the battery itself. Caterhams usually do not require the battery to be vented if they are already in a ventilated area.
On that basis, I'm happy to continue without a vent pipe -- as I have done for the last 22 years!