[tcj911t]

My Interstate U911 batteries needed to be replaced this spring (after 9 years) and I decided to try the Miata AGM batteries recommended in this thread as a replacement this time. I ended up purchasing (2) Marathon AGM Miata batteries from Battery Mart for $99/each (with free shipping) vs. the $150/each for the U911s (including tax). My understanding is that these batteries are the same as several others re-branded on the internet made by East Penn and are generally recommended highly. The batteries are lighter than the Interstate batteries (24 lbs vs 27 lbs) and are slightly different dimensions and need to be fitted a bit. I added some pictures of the Marathon batteries compared to the Interstate batteries and pics of how I installed them in my 911T. I ended up adding a wood block to the back of the battery boxes and then added some plastic shielding to the positive terminal to protect against shorting to the metal. Some other observations I had on the install are:

* The Marathon batteries fit in my 911 battery boxes without needing any modification to the box. The height is a little tight, but not too bad with some plastic or rubber shielding.

* The area around the terminals is tighter that the U911's and I needed to buy a new positive terminal clamp for my right side battery and turn the negative terminal clamps 90 degrees to get them to fit. I am not sure why they limited the room behind the terminals?