Overview

3d CAD model for a battery height spacer to allow installing a shorter group 94R battery in place of a taller 24F or 27F one.

Pros

• 94R is widely available as an AGM battery and much more affordable compared to 27F.
• In terms of capacity, it is a significant upgrade over 24F and comes close to 27F. It usually provides the lowest cost per capacity.
• It has the same size footprint as 27F and therefore fits in the battery compartment of the 4th-gen Toyota 4Runner (N210/N215).

Cons

• It has quite a bit less height (see below for details). This requires bending back the tiny 90° tab on the body ground connector to allow rotating it downwards and securing the clamp to the terminal.
• It has a narrower top with a gap for the folding handles. This is somewhat incompatible with the narrow factory steel hold-down bar.

This spacer provides a longer, sufficiently wide bed for a flat hold-down bar intended for a 24F or 27F battery. The goal is to reduce movement and strain on the battery case.

Status

• 3d model complete.
• Prototype printed using ABS filament with scale factor on printer set to 108% and installed (see photo).

Battery sizes

Capacity and Length/width/height:

• Group 24F (65Ah): 282 168 229
• Group 27F (92Ah): 318 173 227
• Group 94R (H7/L4) (80Ah): 315 175 190

Additional group 94R dimensions

• 121 mm battery width upper
• 12 mm wide and 5 mm deep gap for folding handles across width of battery
• 25 mm step height between outer and inner top of battery

Dimensions of hold-down bar

• 45 mm width
• 8 mm height center
• 12 mm height ends
• 175 mm inside length; spacer needs to fit in there lengthwise

Rough sketch

   175
*****************
*****************
*  121          *

*  45  *
********
   **

Tools used

• ImplicitCAD for programmatic CAD modeling
• MeshLab for 3d mesh rendering
• Cura LulzBot Edition for printing

References

• Deka Intimidator AGM Automotive Flyer