Hi Spencer
Ah-Ha.  The one under the passenger seat.  I must admit the last time I put a battery in it at that location I used a hammer.  Not a big hammer a medium hammer.  It went in after a few taps and does not move around.  When it has to come out, I have a tool, kinda like an ice tong, that will allow me to latch on to it and pull it out.
Samba is a great place to get info. Although I think I would be wary of shaving parrs of the battery off. It doesn't mean that I haven't done crazier things in my time that have worked, 
If you have a trusted mechanic, ask them about that.  There is a reason the engineers put them there.
Whatever you choose to do, Good Luck and let us know. Fun and interesting things await you and your ride.
Dave B.
    On Friday, March 27, 2026 at 07:51:15 AM EDT, Spencer Allen <soxndubs1951@gmail.com> wrote:   

 Dave I don't have an aux battery. Over on the Samba forum a post with pictures shows a 41 battery with the side flanges cut off and the bottom  edge trimmed down. I may try that. The discussion also states a T5 battery is a better fit and same CCA but I'm not sure of the amp hours.  What main battery are you using?Spencer
On Fri, Mar 27, 2026 at 5:55 AM ddbjorkman@verizon.net <ddbjorkman@verizon.net> wrote:

 Hi Spencer
I know what you mean!!
Are you talking about the house or start battery?
Dave B.
    On Thursday, March 26, 2026 at 03:49:23 PM EDT, Spencer Allen <soxndubs1951@gmail.com> wrote:   

 I think my 85 westy's battery box shrank (shrunk?) over winter. For years
I've always had a struggle when dropping the group 41 battery past the
pos-neg cables and have banged-up the pos cables some but always got the
battery in with a bit of maneuvering. today no matter what I did that
battery will not settle into the box. Any tips from those still using the
lead acid battery?
Spencer