You are not reading what he typed correctly he typed "with the panel and sensors pulling 0.55 A"
Now there was no mention of mA so 0.55A no matter how you try to dress that up is slightly over half an amp.
He may have made a mistake but either way what he typed is 0.55A not 0.055A which would be 55mA
One day I'm going to sell up & get a proper job on the tools.
I reckon I could walk into just about anywhere working with just about anything (fire/security) & be the equal of anyone already working there ?
Two things of note here, if your panel is pulling over half an amp quiescent that seems quite high to me and also if your new battery is dropping to 12v under load I would suggest its not a good battery.
cqr used to have clear plastic & you could see them inside
I use to find them inside cables upto 1m or so, I reckon they crawled in, & each time one crawled in behind the they;d move up more ?
battery in sounder will last 2yrs or 20 yrs....