Battery Hydrometer Selection

A battery hydrometer is a fundamental tool for measuring your car battery state of charge.  That said, the device is only useful if you don’t own a maintenance free battery.

Maintenance free batteries are sealed and can not be tested using a hydrometer.

Below are some of the more commonly available hydrometers.   Like most tools, they range in price, quality and performance.

In my humble opinion,  temperature compensated hydrometers are the way to go.


Temperature Correcting Hydrometer

This one is actually manufactured by a battery manufacturer.

The thing to keep in mind is that potentially expensive decisions are made about battery condition  using these tools.   Getting one that with valid indications throughout the temperature range is important.

Expect to pay about fifteen dollars.  They are readily available HERE.

Manufacturer:  East Penn / Deka


Budget Temperature Correcting Hydrometer

This one by OTC has a nice little thermometer with the associated correction factors on the thermometer’s scale.

This one rings in at about eleven bucks and is available online.

Manufacturer: OTC
Model: 4619


Dial Hydrometer

Some people have an easier time reading and interpreting a dial hydrometer than they do the tube and float variety.

The one you see pictured represents just such a hydrometer.

At about eleven and a half dollars,  it is priced right in line with other hydrometers on the market.     It too is ready for immediate delivery HERE.

Manufacturer: E-Z Red
Model: SP101