MGB "Vents" on a new battery?

Went out to start our '74 GT one day, and the alternator light went out as soon as I turned the key to start. Only about a week of not being driven, with the battery cut-off activated. So I put it on charge for several hours, and on trying to start all I got was rapid clicking from the relay that serves as a cut-off. When the battery was pulled out, it was wearing a sticker "January 2008", almost a year before I bought the car.

Decided to replace it with a Westco battery, which fits in the plastic battery bin with almost too much room. Now starts with authority, even on cold days.

The battery has what look like two vent tubes on the top. Nothing is mentioned in the instructions about this. Anyone have experience with this?

Harry

Is this what you're referring to?

https://www.mossmiata.com/Shop/View...SortOrder=10&gclid=CJWogLHBw8oCFYdgfgodf8QD7g

It looks like there is a single piece that covers the cells' access holes, and those are vents for them. If so, I don't see any need to do anything with them.

Steve,
Yep, that's them! I wasn't sure whether to put some tubing on them and lead them out of the bin. Maybe I'll just let them alone, as you suggest.
Thanks,
Harry

I put a Westco Miata battery in my old MGB. I didn't do anything special with those vents.

I don't know why the battery manufacturers do things that way. Back in the Dark Ages, when I was young, batteries had a single cap for each cell, with a pinhole to let out any gasses that evolved from the cell. Then, they went to two caps that covered three cells each. Now, it's one cap for all six cells. There has to be some way to let them breathe; a pinhole or two would be enough, but maybe there's a concern that a small hole on top might get plugged. At least this way you can't drop a cap and have it roll into an inaccessible spot under the workbench.

Cost to manufacture one long cap is probably a lot less than 6 small ones. Things like that are usually a cost issue. PJ

Or, like in both my Volvo and BMW, the battery is in the trunk and there is a concern for an accumulation of hydrogen gas in that enclosed space.
So a vent hose is attached to the nipple on the battery to vent the gasses overboard.

M.

Yes, those are for venting out of an enclosed space like a trunk. My 1998 Z3 has a battery like that. Also vents acid out if it's overfilled or overflows for some reason.

Assuming your battery is in the original location, it's vented plenty well If you've added a battery bin you might want to add the vent tube IF your bin is well sealed up. The holes where the cable run would probably be plenty of venting unless you've sealed those. The other option instead of adding a tube would be to just put a hole or two in the bin to provide that ventilation.

I ended up trimming the very top off my bin. It was thick enough on that top lip to make it difficult to fasten the battery cover. That trimming also provided plenty of ventilation.

Joe,
Thanks, I do have the bins, and there should be enough air dragged through the holes for the cables. I'm thinking I will leave well-enough alone and forget about adding tubing.