Instead of looking for locations for additional batteries, you might look at the option of putting batteries with additional amp hours in the original battery box. About 7 years ago when my 6 volt Gc2's needed replacing, I examined the battery box. It was built with 2 group 31 starting batteries on one side and 4 gc2 6 volt batteries on the other side (400 amp hours from the Gc2's). Three was an angle iron bolted to the box to encapsulate the Gc2 batteries since they are shorter than the group 31 batteries. I removed the angle iron leaving the full length of the battery box for battery space. I installed 4 group 31 size 120 amp hour agm batteries in the box (for 480 total amp hours). They have worked very well, but are now aging out. After some research, I found batteries with the same footprint as the group 31 batteries but the taller height of the 6 volt batteries. I am considering ordering the Vmax Tanks XTR155 agm batteries. Four of them should fit in the original battery box. That will give me 620 amp hours of capacity. I am a bit concerned about weight. The Gc2's weighed about 75 pounds each. The group 31's weighed about 80 pounds each. The XTR155's weigh 90 pounds each. So, my battery box will need be support about 60 pounds more weight then it originally did. The advantage, of course, is that I do not have to find additional space to carry batteries. I hope this works out for me, and thought you might want to consider it as an option.
Richard
