at the end of the charge.

If a battery becomes very hot while on charge at a rate which is not
normally too high for the battery, it indicates that the battery is
badly sulphated, or has a partial short-circuit. Gassing generally
goes with the high temperature.

If you can detect a vinegar-like odor rising from the vent holes, you
may be absolutely sure that the separators used in that battery have
developed acetic acid due to not having received the proper treatment
necessary to prepare them for use in the battery. The electrolyte
should be dumped from such a battery immediately and the battery
should be filled and rinsed with water several times. Then the battery
should be opened without loss of time, to see whether, by removing the
separators and washing the plates thoroughly, the plates may be saved.
If the acetic acid has been present for any length of time, however,
the plates will have been ruined beyond repair, the lead parts being
dissolved by the acid.

If the electrolyte of a battery on charge has a white, milky look,
there may be impurities which cause numerous minute bubbles to form,
such bubbles giving the electrolyte its milky appearance. The milky
appearance may be due to the use of "hard" water in refilling, this
water containing lime.

The electrolyte as seen with the acid of an electric lamp or
flashlight should be perfectly clear and colorless. Any scum,
particles of dirt, any color whatsoever shows that the electrolyte is
impure. This calls for dumping out the electrolyte, filling and
rinsing with pure water, refilling with new electrolyte and putting
the battery back on the charging line. Of course, this may not cause
the battery to charge satisfactorily, which may be due to the troubles
already described.

Should it ever happen that it is impossible to send a current through
a charging circuit go over all the connections to make sure that you
have good contact at each battery terminal, and that there are no
loose inter-cell connectors. If all connections to the batteries are
good, and there are no loose inter-cell connectors, cut out one
battery at a time until you start the current flowing, when you cut
out some particular battery. This battery should then be opened
without further tests, as it is without a doubt in a bad condition.

The conditions which may exist when a battery will not charge, as
shown especially by cadmium tests, are as follows:

(a) The battery may have been allowe