I went to check my battery connections when I had starting problems. It turns out that the place I bought my 2010 panel from had placed the wrong battery in the rear compartment. It has plenty of power, but it is not vented. The hole in the flood is visible but no tube. Is there some way I can vent this existing battery, or just get a new vented one?

 

Just get the right battery. It's not worth fooling around with.

 

Maybe it is the correct battery and they didn't put a tube back in place ? Sometimes when replacing the battery, the tube gets broken off and it doesn't get replaced.
Check for the small vent tube hole on the upper side of the battery. (it is hard to see)

 

I figured I should just get the correct battery.

 

It should be like this, the grey tube is the vent tube

 

What group (size) battery is there now?

 

These days many batteries have a vent hole and are suitable fit.

 

I was wondering what that grey tube is , now I know

 

More battery power requires a more powerful generator.
The standard HHR generator can be helpless when charging and this will be a problem.
As for the tube, you don't have to worry about it. The task of the tube is very simple - to remove the side gas to the outside environment. This is more a fiction than real security. The battery emits so little gas that you simply won't notice it. Unless you take apart the interior and stick your nose right into the battery vent. But even so, you are unlikely to feel anything.
I've changed my battery twice already, and all these years my pipe has been dangling somewhere at the bottom. I don't even know if it is in place today or has already fallen off and lost.

PS. Yes, buy a new standard battery according to the manufacturer's recommendations. You can give the powerful battery to the seller as a partial payment.

 

Our stock size batteries are T 5, fwiw.