I have an Oxford optimizer on the Wall of my garage and I fitted a fused SAE connector under my rear seat on my 99. I had one fail and it was because of a Design weakness because the 12V wire flexes and wears and can then short at the box. I've cured this as in this picture with a Tie-Wrap,
I've got one of these in my Kitchen to keep my spare M/C battery charged,
https://www.ebay.co.uk/itm/304244752...%3AAQAIAAAA8Kb
Does the job and charges fast and can be used on cars as well if needed.
HTH