Jim Dunmyer wrote in a message to Roy J. Tellason:
 > I've also been fiddling a bit with an old (couple of decades) Exide 
 > emergency lighting box model ESS.  This is one of a bunch of these 
 > 
 > This thing was originally designed to hold a "wet" 6v/30AH battery 
 > 
 > Anyone know how long emergency lights are supposed to stay lit?
 JD> I have one that sounds identical to what you describe; I got it 
 JD> from a building that was being remodeled. 
I got mine from a guy who brought in some batteries that he wanted to dispose 
of,  told me that the church had replaced all of their emergency lighting 
with newer stuff.  I asked him if the old lights were still around,  and he 
said yeah,  and brought 'em in for me.
 JD> The unit had been unplugged for several years when I obtained 
 JD> it. All I did was plug 'er in and wait until it started taking a
 JD> charge. That took several hours.
I kept one of the batteries out of this unit as a thing to display in the 
window.  It had *no* electrolyte in it whatsoever,  probably from it not 
having been maintained over the years.  There were seriously warped plates 
(no doubt made that way as the thing was cooked dry) and a little 
"hydrometer" built into one of the cells with little plastic discs that would 
show you what the state of charge was.
 JD> I've had it run for well over an hour during an outage, maybe 
 JD> even a couple of hours.
I've got one sitting out in the other room now that took quite a while to go 
off "high rate" charge,  which still didn't go up to 7.5v on the built-in 
voltmeter (which I gather from the little list inside was an "option").  The 
"ready" light flickers now and again,  and the test button produces quite a 
bit of light.  This is one of the few that have _two_ sealed beams on the 
top, most of them had one as I recall.
I've got a couple of 6v/33ah gel batteries and one's in this now.  I oughta 
charge up the other one,  I guess.
I did some tracing out of the circuitry in there,  and it's not all *that* 
complicated,  though I'd rather get a schematic if that's possible.  It'd be 
neat to duplicate some of the circuitry for an automatic charger for some of 
the other stuff I've got here.
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