Occasionally I receive reports of a fixture without AC power therefore it needs to be replaced. I understand (I believe) the concept that a fixture is tied into a buildings AC power system and use AC power to keep their battery charged and when the building loses power, the fixture will operate as intended. My question is, do all standard fixtures come with this feature and/or how does one determine this fixture?
I don't really understand the fixture without AC power part. Emergency ballast is like a miniature UPS that operates the lamps off the battery, generally at partial output. Some outputs high voltage DC using a power supply like the kind used to power an old tube Tele.
DC output is bad for lamps, but it's not intended to be something you do often and it's downright incompatible with some light emitting friode lamps.
Fluorescent emergency generally uses NiCd, but halogen ones use lead acid. The lead acid battery is ruined if it is discharged and left discharged, usually in a matter of week or so. Perhaps this is what they mean?
