I had my original battery replaced by a non-sealed one. What maintenance issues do I need to be aware of? I haven't owned a non-sealed battery in many years. How often should I check the level? I have a Cooper R52 and I'd have to take off the strut brace even just to check. I remember that many years ago, after replacing a Honda OEM sealed battery with non-sealed, the terminals would develop fuzz and corrision that was not occurring previously. Should I expect this to happen again?

Here's the background story. My battery is 3 years old. I had some warning about the battery condition -- the factory Nav screen was taking about a minute to start up (others have reported that this is an indication of the battery starting to go dead). It is still under warranty but there were no other electrical issues and the car was starting normally, so I didn't think it was urgent to take in right away. About two weeks after noticing the Nav issue, the car suddenly wouldn't start on a Friday morning. After a jump, it ran fine for the rest of the day. The next morning (Saturday), it wouldn't start again, and the dealer isn't open for service. The MINI is our only car and we needed a reliable car all weekend, so I bit the bullet and gave up the free warranty replacement. I called the AAA battery service and they replaced the battery at my house. Final price was $135, not too bad for full door-to-door replacement service, and I only had to wait 20 minutes for them to arrive. The replacement is a non-sealed battery with no manufacturer markings (just AAA stickers). It has no place to connect a vent tube. It comes with a 3 year replacement guarantee followed by additional 3 years pro-rated warranty.

 

The battery should be vented to the outside. I wouldn't run a non-vented battery inside the passagener compartment because the battery can emit sulfuric acid fumes and breathing sulfuric acid mists can result in tooth erosion and respiratory tract irritation.

If you still have the old battery, take it back to the dealer and exchange it under warranty and install it as soon as possible.

 

The car is a non-S Cooper cabrio (battery up front in the engine compartment).

 

batteries these days are maintenance free. check the sticker on the battery you purchased for more info.