Switzerland
manufactured "dry" electrolyte storage batteries in commercial
quantities. These batteries were for a long time a distinct success
for work requiring only low rates of discharge. For high rates of
discharge the lack of diffusion, due to the absence of a liquid
electrolyte, reduces the capacity. The lack of diffusion will cause a
rapid drop in voltage when cranking the engine! and a slow recovery
after the engine begins to run under its own power.

The manufacturers of the "dry" storage batteries, of course, claim
that their batteries are more efficient and satisfactory than the
standard "wet" battery, but it has been impossible to get sufficient
data from the manufacturers to go into detail on the subject.

Several of the largest of "wet" battery manufacturers formerly made
"dry" storage batteries for lighting and ignition service, but when
starting motors came into use, discarded the "dry" batteries in favor
of the present "wet" storage batteries.

DISCHARGE TESTS

Discharge tests may be divided into four general classes:

(a) Brief High Rate Discharge Tests to determine condition of battery.
These tests are made for 15 seconds at a high rate.

(b) Lighting Ability Discharge Tests.

(c) Starting Ability Discharge Tests.

(d) "Cycling" Discharge Tests.

The 15 Seconds High Rate Discharge Test

The 1.5 seconds high rate discharge test is a valuable aid in
determining the condition of a battery, particularly where the
hydrometer readings give false indications, such as is the case when
electrolyte or acid is added to a cell instead of water to replace
evaporation. Only two or three percent of the battery capacity is
consumed by the test, and it is not usually necessary to recharge the
battery after making the test. The test must be made in conjunction
with hydrometer readings, as otherwise it might give false indications
itself. Both incoming and outgoing batteries may be tested, and the
method of testing depends upon whether the battery is coming in for
repairs, or is going out after having been charged, repaired, or
worked on in any way. In either case, the test consists of discharging
the battery at a high rate for a short time, and taking voltage
readings and making observations while the battery is discharging.

[Fig. 179 Making a 20 seconds high rate discharge test]

Rates of Discharge. It is not necessary to have any definitely fixed
discharge rate. The rate should merely be hig