My wife bought a new car battery from WalMart. Before putting it in, I popped those flat plastic lids on it to check the fluid level. All these batteries are supposed to be..."lifetime maintenance free". That is: they do not want you to check the fluid level (like in the old days) and to add distilled water.
Anyway, each side of the battery (there are 2 plastic flat covers for the cells on the top of the car battery), each side was down at least 1 1/2 inches below the top. That is: it appears to be LOW on battery fluid, even as I bought it new.
My questions: should the battery actually be near the top on fluid? And, if in the lifetime of this battery I have to add fluid...would I add distilled water? Or, would I have to come up with an acid/water mix to add to these modern batteries?
"maintainence free" is a marketing slogan not an engineering term.
Usually, if the battery says "maintainence free" it is a conventional lead-acid that you check the battery fluid as part of your preventative maintainence.
If it says "sealed maintainence free" then it's a sealed one that you do not check the water.
NEVER add acid to a battery! The only kind of lead acid battery that you add acid/water to is a motorcycle battery that is sold DRY. However, even these nowadays are coming with acid/water in a bottle instead of the old smaller bottle that was acid only and you mixed it with water. Too many people causing acid explosions I guess because of not properly mixing the two, so the factories decided the liability wasn't worth the nickel saved by not premixing the acid and water.
ONLY add water to a battery. If your in a jurisdiction that has very pure and soft water you can use tap water. However if your in an area that has mineral content in the water of any appreciable amount, you must use distilled water.
As far as topping up this battery - you should do the following. First, put the new battery on a battery charger until the battery is fully charged according to the charger. Next, use a battery hydrometer and measure the specific gravity of each cell. If all cells are equivalent, and the specific gravity of the cells is UNDER OR EQUAL TO 1.285 then LEAVE IT ALONE. If the specific gravity is higher but still under 1.3 then it may be that the battery is excessively warm, I would STILL leave it alone, and run it in the car for a few weeks, and then check it again.
Of course, this assumes you are using a GOOD battery hydrometer with a scale, and that is calibrated. Pure water is 1.0 and acid is generally 1.4 but to accurately calibrate a hydrometer you need to weigh a measured sample of acid and calculate it's specific gravity then see if the hydrometer agrees with this. (or buy a calibrated hydrometer, about $100) Thus, don't be too worried if the specific gravity of the cells measured isn't exact.
IF, however, the specific gravity is higher, then some of the water has been boiled off and you can add water to the battery in small increments, allowing it to mix for a couple days while you drive the car around, then remeasure the specific gravity again.
Once you get the SG to where it's supposed to be, then MAKE A NOTE of where the fluid level is, and when you check the battery level, refill it to that level.
Don't just blindly fill up a modern battery to some arbitrary measurement or mark.
Normally, a battery with a pure acid/water mix will outgas when fully charged, if charge voltage is applied to it. This is normal, and the gas is hydrogen and oxygen, caused by the battery decomposing the water in the acid water mix. These need to be frequently checked.
However what many manufacturers do these days is to add a small catalyst to the electrolyte, this makes most of the hydrogen and oxygen recombine in the battery. Thus, the advantage is that less electrolyte is needed. If you overfill these batteries with water it DOES NOT hurt the battery - BUT it REDUCES the battery capacity. Gradually over time the capacity will come back as the extra water goes away due to normal decomposition.
Now, many people will say don't bother to check the water level in the battery. DON'T LISTEN TO THEM. In a car battery with a catalyst in the electrolyte, if the charging voltage is maintained properly, you generally have little water loss.
BUT, if the charging circuit increases charging voltage on the battery, due to component failure or whatever, then the battery will start to decompose the water, despite the presence of the catalyst. The level will start dropping and the specific gravity will start rising, and once it goes about 1.33 or so, the plates will start disintegrating and sulfating and the battery will be ruined. So, check the electrolyte level in the battery at every oil change, it can serve as a good early warning indicator for charging circuit problems.
Don't fill it to the top unless you want a dead battery. If you look down into the holes of each cell there is a recess (plastic tube molded to the top of the battery with a slot cut into the side) reaching downward from the top of the hole. The electrolyte need only be touching the BOTTOM of the recess. Any fuller will "flood" the battery (make it one big box of acid instead of 6 separate ones) & kill it. Good luck.
The 'maintenance free' bull shit has to be one of the best marketing sleazes going!
Those batteries still lose fluid, just at a slower rate. The catch is you 'can't' top most of them up so what should just be 2 cents worth of distilled water turns into a hundred dollar purchase.
Total BS!
I know a gent that takes all the 'dead' batteries from car lots, opens them up, tops the water back up, puts a charge in them and sells them back for 30 bucks 'with' a one year warranty.
He says he 'never' has to honor the warranty!
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
----- I bought a new battery, years ago, and noticed one cell was "using" water much more than the others. I added pre-mixed electrolyte to the cell, a few times, until its water use became equal to the others. Five years later, when I traded in the car, the battery was still good.
-- ,_, Lionel The more I hear about other people's problems, (O,O) Wagner the better I feel about my own. ( ) -------------------------"-"-
I live in Arizona, and back when maintenance-free Delcos were made of translucent plastic that let you see the fluid level by shining a flashlight behind the battery, neither my father nor I ever saw it drop too much, and he kept batteries an average of 4-5 years. Also I've had maintenance-free batteries from Wal-mart and Pep Boys that were probably made by GNB and had removable caps, and their fluid levels never dropped much, either, while the newer Wal-marts, by Johnson Controls, drop noticeably every three months.
In side each filler hole is a plastic "finger" or tube molded into the battery top that's supposed to indicate when the water level if full. I used to think that when the cell was full when its water level just touched the bottom of the tube or finger, but in every battery I've bought that had removable caps, the water level was 1/4" below that. I thought that this was too low, so I once phoned Exide and Johnson Controls (makes several brands, like Interstate, Diehard, and Wal-mart), and they told me that this was normal. Johnson Controls said that all their batteries except their Eveready brand are not maintenance-free but require fluid inspection every few months. They said that maintenance-free batteries are more likely to be ruined if the headlights are accidentally left on overnight while low-maintenance batteries can recover from this a few times if recharged.
The term "Maintenance Free" denotes the Calcium/Calcium plate construction and battery type and the water usage is lower than Standard (Sb/Sb) or Low Maintenance (Sb/Ca) battery types. In hot climates, you will consume more water than in cold climates and batteries where the water can be added is usually a much better choice.
Electrolyte needs to cover the plates at all times to prevent the uncovered areas form sulfating and the loss of battery capacity. The question of electrolyte levels has to do with temperature. If you overfill your battery, the electrolyte will expand as the battery heats up and could cause corrosion, discharge paths across the top of your battery, and a mess. Unless you have spilled electrolyte from your battery, add only distilled, deionized or demineratived water and not tap water because tap water will cause Calcium sulfation and reduce the capacity of your battery.
For additional information of preventative maintenance and recommended refilling levels, please read Section 3 of the Car and Deep Cycle Battery FAQ on
formatting link
A good quality, temperature compensating hydrometer, like a EZ-Red SP 101, can be purchased for under $10. A good hydrometer is a highly recommended piece of test equipment for accurately testing the State-of-Charge of your wet lead-acid batteries once the surface charge has been removed. Please see Section 4 for battery testing.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.