so called maintenance free batteries

[wilson ind]

Post below got me thinking . Possible bad thing!! In the past I have drilled into batteries with no caps to add water. Only on batteries of say 4 years. If filled to close to opening seems to work well and have used same for many more years.

 

[kevinthefixer]

Some manufacturers were making "maintenance free" batteries by simply leaving out the holes to fill them. In an automotive application they'll still last three to five years usually, enough to get out of warranty, and then they sell another battery which has a much better profit margin than a jug of distilled water.

 

[sotxbill]

Maintenance Free Type

Maintenance free battery incorporates several modifications over a conventional battery, the most significant feature is that it is sealed (except for a very small vent-hole) and requires no service attention other than to be kept clean.
The Delco-Remy Freedom maintenance free (Fig. 13.70) battery first appeared in America in 1971. In addition to being maintenance-free, this battery offers better cold weather starting power and improved resistance to heat and vibration damage.
The antimony has been eliminated from the plate grids, which could remove four major causes of early battery failure such as overcharge, water usage, thermal-runaway and self discharge. Thermal runaway is a condition, which occurs in a conventional battery when the battery operating temperature is high or when faulty regulation of the charging system is combined with a rising electrolyte temperature.
Overcharge is the major cause of gassing in a conventional battery. In a Freedom battery lead calcium (Pb Ca) is used for the grid material. Therefore with the inherent assistance of the higher emf given by this construction as it approaches full-charge, it is possible to reduce loss

 

[Geo-TH,In]

Bill,
I heard of a man who drilled holes and the sparks form drill caused an explosion.

The upside to AGM batteries is they don't vent and less likely for terminals to oxidize. Both my GM vehicles came from factory with AGM. The dealer wanted $165 for new delco battery. I learned form you how to be cheap. So I went to Rural King and bought my favorite cheap excide battery for $45. The excide battery lasted longer than the AGM, however I removed the battery holder on truck, removed all the rust caused by the vented battery, gave it a few coats of rustolum. Both car and truck AGM's were replaced with excides. After 5.5 years of good service, I replaced both and am now using the old batteries in my dump trailer. They are still working, over 6 years old.

So, I'll never spend more money on an AGM when I can buy about 4 excide vented batteries and get good service out of them.

I will buy, on sale, excide AGM mower batteries. I like them because a bouncing lawn mower can't splash the electrolyte out and less oxidation on terminals. I'm getting good service out of them on mowers.
geo

 

[sotxbill]

I posted this because there is a confusion between what some folks call... maintenance free batteries. For us older folks, we have had the maintenance free batteries around a long time.

Yes the seal batteries are NOW also called maintenance free batteries also.

Some manufactures simply changed the lead alloy, and also added a layer of oil to float over the top of the electrolytic( to reduce/slow down evaporation).. And this worked well till the cell level eventually got lower and the oil then shorted the cells plates out.. So those batteries worked fine one day and totally dead the next. Also did not like to be bounce around when a bit low on fluid.

Some aftermarket companies even sold a battery oil to add on top of the electrolytic. I have a very very old glass container of Edison Battery Oil.