How to use a hydrometer.

This video shows how to check the specific gravity of a lead acid battery using a hydrometer.
Mechanical Engineering tutorials videos
As you can see in the video, hydrometer consists of a glass tube which has a float inside. On the bottom of the hydrometer we have the suction tube, for sucking electrolyte. On the top we have a rubber bulb, which is squeezed to suck the electrolyte into the hydrometer tube.
As the electrolyte enters the tube, the float tends to move. So we can get the specific gravity at the scale of the float where the electrolyte rests.   Hydraulic tutorials

This specific gravity reading can give us a clear idea about the condition of the battery.
Check the Specific Gravity with Hydrometer.
 If Specific Gravity is
 Greater than 1.250 - adjust with distilled water to ensure SG of 1.240
 1.240 to 1.230 - Battery is in charged condition
 1.220 to 1.200 - Battery is partially charged
 Less than 1.200 - Battery is highly discharged.
Recharging guidelines:
1.240 - Battery is fully charged. No charging is required.
1.230 to 1.240 - Freshening Charge is required. It can be done on the machine itself during the normal course of machine operation, with all the electrical appliances switched off. Else we need to get it charged externally. Usually gets fully charged in 1-2 hours.
Less than 1.200 - Full recharging needs to be done, which can take anywhere between 8 to 48hrs.depending on the SG value.

Mechanical Engineering tutorials videos

2 comments:

  1. I just wanted to know something very basic about battery hydrometer.
    The hydrometer works on archimedes principle which we all know.
    so my question to you is that:-
    1)how exactly the electrolyte gets sucked in when we squeeze the rubber bulb??
    2) how much do we have to actually squeeze the bulb???
    3) were to place the hydrometer's sucking rubber bulb inside the battery like it should be on the surface or should it be dipped inside
    the liquid???

    Thanks n Regards,
    Praveen

    ReplyDelete
  2. Hi.
    Please have a look at the video and it have all the answers.

    ReplyDelete