Battery Testers

Hydrometer

SIZE: 8-1/2 to 11 in.

MATERIAL: Barrel float: glass; Bulb: rubber

USE: To check the state of charge of a car battery

An hydrometer checks the charge of a battery by measuring the specific gravity of the electrolyte in the cells.

You can check the charge each month by squeezing the bulb on the hydrometer, inserting the nozzle in the cell and drawing off some of the diluted acid by slowly releasing the bulb. When the float is clear of the bottom, read off the state of charge on the float where it emerges from the electrolyte. The lower the charge in the

battery, the deeper the float will sink into the electrolyte.

Some floats indicate full or half charge. A graduated scale will indicate a full charge between 1.250 and 1.350.

Once you have taken the reading, return the electrolyte to the cell and check each cell in turn. Wash out the hydrometer after use.

Circuit Tester

SIZE: To measure 6, 12, 24 volt systems

MATERIAL: Various

USE: To test the presence of electricity in an automobile wiring system

The tester isolates the faulty section of a circuit. It has a pointed probe in a plastic handle, which contains a test bulb. The other end of the handle is connected to a crocodile clip by a length of cable. The point on the probe will pierce the insulation on a cable.

By attaching the clip to a ground point, the probe makes contact with the live section of the circuit and the bulb lights up if electricity is present.

This type of tester can only be used on low voltage systems, and should not be used on a high voltage system such as house wiring.