Car Battery Water Level Decreases Frequently

[Prashanweera]

Hi All,

My car has reguler car bettery. I observe that it's water level decreases frequently. But car is starting without any issue. What could be the reason fro this ?

Is this because the battery is old ? Could it be due to problem with over charging ? One mechanic told me that the water get boiled and evoporate. He recomend an maintanance free battery. What do you thik about it ?

Please help me.

Regards.

[maheshw]

well not an expert. did you chek whether the alternator out put? is your car overcharging? is battery water split over the bettry ?

[Rumesh88]

What your mech told you is total BS. You have not told the model of your car to get an idea of what type of charging system there is because there are early car models with mechanical regulators which can be adjusted. However what you need to do is get the battery voltage measured with an accurate digital voltmeter, both with and without your electrical loads (AC head lights etc) on and engine revs at 2000 rpm. The charging systems are different from one car model to another but in general most JDMs have their charging voltage set at around 14.2V +/- a couple of decimals. Now if it is around 14.5 and your car is mostly used in the day time (and at an ambient temperature above 25C) chances are that your battery is being overcharged and that it is the reason for the water level to go down. Now maintenance free batteries are more sensitive to over charging than freely ventilated (just a technical jargon) batteries. Mounting a maintenance free battery in your case will solve your problem of having to refill it ever so often but you would not get the expected service life of the battery.

Edit:Are you having the stock alternator or has it being changed at any time?

Edited April 23, 2014 by Rumesh88

[wolseley]

There should be a reason for battery level drop.

* extreme high temperature

* a leak

* over charging

In your case I think it is due to over charging. There is no boiling in over charging. Hydrogen bubbles come up when the battery is full and keep charging.

However because of bubbling the electrolyte will evaporate causing the drop of level.

Go to a battery dealer and get it checked and rectified if there is any issue.

[MasterDon]

Most probably a crack in the casing.It can happen due to a battery's age or over charging.Start the car and rev it hard,if its a crack you'll see water seeping out.

[Prashanweera]

Hi All,

What your mech told you is total BS. You have not told the model of your car to get an idea of what type of charging system there is because there are early car models with mechanical regulators which can be adjusted. However what you need to do is get the battery voltage measured with an accurate digital voltmeter, both with and without your electrical loads (AC head lights etc) on and engine revs at 2000 rpm. The charging systems are different from one car model to another but in general most JDMs have their charging voltage set at around 14.2V +/- a couple of decimals. Now if it is around 14.5 and your car is mostly used in the day time (and at an ambient temperature above 25C) chances are that your battery is being overcharged and that it is the reason for the water level to go down. Now maintenance free batteries are more sensitive to over charging than freely ventilated (just a technical jargon) batteries. Mounting a maintenance free battery in your case will solve your problem of having to refill it ever so often but you would not get the expected service life of the battery.

Edit:Are you having the stock alternator or has it being changed at any time?

Hi Romesh,

Thank you for replying me. The car is Micro Kyron.. I'll do the voltage test on this saturday and let you know the values.

[Rumesh88]

Hi Romesh,

Thank you for replying me. The car is Micro Kyron.. I'll do the voltage test on this saturday and let you know the values.

Ah! one more thing. Do the measurement after a run of about 10 minutes or more and most importantly do it without stopping the engine. If you stop the engine and restart you would not get the right value if you measure it immediately.

[codexdj]

Probably a battery casing crack! Remove the battery from lugs (minus terminal first and then the plus terminal). > Remove the battery and check the battery resting plate for recent corrosion and/or leakages/spilled water.

[Prashanweera]

Hi All,

I measure the batter voltage in vehicle idle state after starting it for more than 15 min.

The idle state voltage is 14.37 V ~ 14.38 V. Is this normal ?

[Rumesh88]

Hi All,

I measure the batter voltage in vehicle idle state after starting it for more than 15 min.

The idle state voltage is 14.37 V ~ 14.38 V. Is this normal ?

It is marginally on the high side for warm climatic conditions but not too high to warrant any immediate action. If you have to top up battery water at something like every 2000kms of mainly daytime running, then it could be due to slight over charging. You can either live with it or if it still bothers you, then get your grounding connections (battery to chassis, chassis to engine block) visually checked. Another way to check if there is an abnormality in grounding connection is to check if there is an appreciable voltage drop (like 0.2V) between the alternator body and the -ve terminal of the battery under the above loading conditions. I am assuming an accurate meter and the figures given are for guidance only. But if there is a drop you can either rectify it or use a grounding kit like the one used in http://forum.autolanka.com/topic/15784-project-carina-gt/page-5 .Of course there are alternator giving charge voltages as high as 14.5 but only under high load conditions.

[codexdj]

Btw, I just replaced my 2 year old e#ide battery with am#ron maintenance free one. The price difference is about 2000 and the lifetime is 1 year more. You don't have to worry about water levels. Comes with a 2 year one to one replacement warranty as well. I highly recommend to buy one for your car.

Edited June 6, 2014 by codexdj