"Percival P. Cassidy" wrote in message
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snip

While looking for a hydrometer today, I noticed "Vector" brand "smart"
chargers (10/6/2A and 6/4/2A) that claimed to have 3-stage charging
circuitry and to be suitable for car batteries, deep-cycle batteries, and
gel-cell batteries. Are these likely to be any good?

The battery was still warm, and each cell was still bubbling slightly
after the thing had been disconnected from the charger for about 3 hours.
The SG of each cell was pretty much the same at approx. 1.1175, and the
voltage across the whole battery was 12.4. When I put it back on charge,
the voltage rose to 13.3.

What do you think?


If the charger was disconnected and the battery open-circuited for 3 hours,
there shouldn't be any *active* bubbling going on. There may be some
bubbles still 'stuck' to the plates, but no new bubbles should be forming.
If there is after 3 hours of open circuit, that would be a sign of internal
current flow (an internal short). And that would be bad.

SG on lead acid batteries have a couple of different ranges depending on the
exact battery details. I've seen 1.250, 1.265 and 1.280 for fully charged.
1.117 seems very low.

The fact that all cells read the same is a good sign. Usually, one cell
will fail before the others and so it's SG will be decidedly lower.

Such a low SG makes me wonder if maybe the electrolyte was lost from
spillage or something and *not* just discharge and electrolysis.
Evaporation and electrolysis just leaves a stronger acid solution chemicals
behind and adding distilled water dilutes it back to the proper
concentration. Actual spilling of acid from a cell needs to be replaced
with new acid of the proper concentration though.

daestrom