Hello, My materials specifications. 12V/12AH Lead-Acid Battery 12V/5W Compact Fluorescent Lamp, YES it is. I have calculate how many hours can the lead acid battery run the cfl. it's about 28. due to some safety reasons, let's move it to 10 hours. My question is. OK, I runned the lamp 10 hours. can the battery voltage still the same from the first to the last (after 10 hours) or there will be a voltage down/drop? Thanks.