Guys...

The reason some packs fit and others don't is the way the pack is constructed. Some are flat 3x2 layout, others are flat sideby-6 layout.

Another thing is ~endcaps~. Some manufacturers put plastic endcaps on their packs to protect 'em, especially common with buggy packs. This would make the pack longer, and hence it won't fit in your compartment.

The last thing is how the power leads are attached. If they come directly off the end, common on the 2x3 packs, they add some length, again causing a fit problem.

When in doubt and buying online, ask the seller for the pack dimensions... but the critical one is usually the ~length~, and how the power leads are attached.

WhiteWolf