I decided to finally give the repro battery a transplant, and even though I could have saved a few bucks by going with a 925, I decided to replace them with the original 680 style batteries after giving me 18 years of reliable service.
I first cut the top off right under the lid lip with a cutoff wheel on a Dremel
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After that I cut out the bottom by drilling a series of holes and finishing it off with a cutoff wheel. I had to be very careful with the drill placement since there was very little room between the battery case and the inside wall
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Once the floor and batteries were removed I could install the 1/8" black plexiglass floor
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Extra adhesive was added to the inside perimeter where the floor meets the case since it will be permanent. Installed new batteries with strips of velcro on the bottoms to prevent lateral movement, as well as ease of future replacement.
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Once the batteries were in and connected I secured the lid with a thick bead of ultra black rtv, let it fully cure, and trimmed the squeeze-out with a utility blade. When the time comes to replace the batteries again it's only a matter of breaking the seal under the lid with a blade and removing everything from the top.
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