For various reasons, I want to install a dual battery system in my 2011 Honda Accord LX-S. I would prefer to not put the auxiliary battery in the trunk so I was looking at the current battery compartment layout. The vehicle uses a Group Size 51R battery (rather small at 9 3/8" L, 5 1/16" W & 8 13/16" H). The current battery compartment appears over sized and was made for a much larger battery.

I did not take out the battery but I was curious if the current battery compartment and bottom mounting plate could be removed and a nice custom dual battery compartment be fabricated by a sheet metal shop. Without measuring, it appears if the battery was turned 90 degrees that two Group Size 51R batteries might fit in the space.

Any readers know if the bottom battery plate can be easily removed or is it welded onto the body? If the batteries were turned, do you think there be sufficient room for two Group 51R batteries?

While I am on the topic of dual battery systems, can anyone recommend high quality dual battery rectifier & isolator systems/kits?

I would welcome any feedback on my rough idea and suggestions where I might otherwise locate the second auxiliary battery. Thanks!