# How do you know when your battery needs water?



## snoozy (May 10, 2002)

I didn't realize that modern car batteries still might need topping up with water. How do you know when it might need it? 

Also, my brake fluid thingee shows the brake fluid in the middle between the "full" and the "need to fill" lines. Would it be a good idea to top that up? (Can one top it up, or do you have to completely drain it and replace it and bleed lines and all that stuff that I don't know how to do?)


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## Windy in Kansas (Jun 16, 2002)

Most car and truck batteries are now sealed so that one cannot add any water to them.

For brake fluid, just top it off to the proper level.


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## snoozy (May 10, 2002)

My car battery has hinged plastic caps which you can flip up and look into. Does that make a difference?


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## raymilosh (Jan 12, 2005)

around here, i'd say about 3 of 4 batteries still have caps that can be opened. there are 2 caps. each cap covers 3 cells.

look into each cell. the fluid level should be above the top of the plates. If it is not, add DISTILLED water, not tap water until the fluid is above the plates and below the level where the fluid touches the plastic cylinder that extends downward inside the cell around the hole. Hmm. that's difficult to explain.


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## Windy in Kansas (Jun 16, 2002)

Does make a big difference. I've not seen one with the opening caps for nearly 10 years. Must be that some company has the market here with the completely sealed ones.

Sorry snoozy I really didn't know they were still around.


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## wasajco1911a1 (Apr 26, 2009)

Brake fluid is not consumed, if it was filled when new brakes where put on, or when vehicle was new, showing half down merely means that the pads and or shoes are wearing down and checking them is not a bad idea. Lots of aftermarket batteries, such as the ones sold at WalMart and Interstate batteries need water added, especially in GM cars, their higher voltage charging systems tend to boil off the water faster, than say a Chrysler product. When you look down the hole, unless you see a meniscus that is open at six o.clock and twelve o'clock, it needs water. And you REALLY do need to use distilled water, otherwise you will make your battery die early. BTW, clean the top of the battery well with water and blow dry before you add water, dirt in the cells is bad as well. Keep some baking soda and water handy in case you get some acid on you. Water only dilutes it, baking soda and water neutralizes it.


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## snoozy (May 10, 2002)

Thank you for explaining that! When one understands the mechanisms or reasons for things, it all makes much more sense.


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## Wis Bang (Feb 20, 2009)

Windy in Kansas said:


> Does make a big difference. I've not seen one with the opening caps for nearly 10 years. Must be that some company has the market here with the completely sealed ones.
> 
> Sorry snoozy I really didn't know they were still around.


Alot of the 'sealed' units can be opened and filled, it just takes some doing to get them open...


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## Dave (May 10, 2002)

Yup, I've yet to run into one of the sealed batteries I can't pry the caps off of. Lots of batteries are also still made with easily removed caps.


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