Re: (ET) charger problem

["Paul Heinzerling" <plheinzerling windstream net>]

Antimony vs. Calcium:

This is going to be VERY unscientific, but may be useful.

In a former life, I spec'd and operated the backup power system for the 
Roadway Express corporate headquarters and data center in Akron.  A portion 
of this was a three-unit 480V rotary UPS system with a room full of 720 2V 
Exide wet cells of the kind you used to see in telephone backup 
applications.  I did a lot of careful research, most of the details of which 
I have blissfully forgotten.  Here are a few things (without numbers) that I 
can say with confidence that I remember:

The main advantage of the lead-calcium grid is that the battery gasses much 
less (maybe 90%less) during charge and particularly at the end of charge. 
As you can imagine, this is a huge advantage in ventilating hydrogen from a 
battery room.  A consequent advantage is that re-watering requirements are 
much less.

The end-of-charge and float voltage requirements are higher for the 
lead-calcium battery than for the lead-antimony battery.

Lead-calcium batteries are more expensive.

I don't remember any paticular differences in the durability of either 
chemistry, except that the lead-antimony might have a slight advantage.

When you see a common battery (automotive, golf cart, marine, etc.) if you 
can refill it, it is probably lead-antimony.  Because of higher gassing, it 
will lose water and need to be refilled.  When the battery is advertised as 
"no maintenance" and there is no way to refill it, it is probably 
lead-calcium.  They are built with an extra reserve of electrolyte to 
account for the minimal gassing and water loss of this chemistry.  An 
example of this is the old Delco "Voyager" deep-cycle marine battery, three 
of which I am still using after some 15 years.

I'm willing to bet that most of the batteries we are dealing with are 
lead-antimony.

Paul Heinzerling
Hudson, OH