What's this pipe in the Battery Tray?

Technical Area Engine, Transmission, Exhaust etc
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  1. My model of MX-5 is: 2003 Mk2.5 NBFL
  2. I’m based near: Oxford
  3. I’m looking for technical help or recommendations on: an unidentified pipe near the battery tray.

(I like the template, very useful!!)

I noticed this pipe today after I moved the battery out of the tray. Any ideas what it is?

Thanks.

Darren.

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To allow the battery to vent gasses outside of the boot space. The original Panasonic “AGM” battery has fittings at each end that the pips slip onto. Any battery fitted really needs to have equivalent fittings.

3

Robbie, your Technical Adviser title needs to be upgraded to Genius.

Thank you! Do I need to connect it to anything?

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I think I edited my reply as you were replying and answered your question.

What battery have you got?

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The battery is by LINCON and the label says 44Ah20hr - 400EN (K16 063SMF).

Doesn’t mean much to me but I see no places on it to connect breathing pipes to.

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‘Ordinary’ batteries usually have small breather holes but you might need narrower bits of tube or elbows to connect to them. Maybe they are still in your car. On a new battery one or both holes might have a red plug in them. I don’t suppose anybody reads the instructions with a new battery but the plugs should be removed.

If there is a vent tube for one hole only, you should leave the bung in the other one.

Cars that have the battery in the boot usually have vent tubes. The ones under the bonnet usually just let the hydrogen vent to atmosphere.

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Thank you!
I’ll take a look tomorrow for somewhere to plug the breather tube into on the battery.

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Looking at thir website, these look like very conventional lead acid batteries. The surface rusting at the bottom of the battery well is why Panasonic batteries were fitted.

On my Jag, the battery is in the boot. I replaced the original Jaguar (Lucas) battery with a new one, and found the male connectors from the old could be transferred to the new one, which had the holes but not the connectors. If your battery has these holes, you might need to get some straight hose connectors, similar to those used in screen washer tubes.

The battery in my MX5 right now is a standard lead acid battery. It doesn’t have these connectors. COVID killed the 2 year old Panasonic I had in there (it doesn’t really hold charge and I think was the cause of the hot cranking problems I was encountering). I keep the car stored in the garage, with the boot propped open to vent.

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