Better way to check battery SG?

ktmrfs wrote:

Gdetrailer wrote:
All I have ever used for batteries is the simplest, cheapest "ball" type in a tube Hydrometer..

Sort of like this one..



All of the balls rise, the battery is fully charged..

Simple, cheap and effective.

These work ok to tell if a battery is well on it's way out, but not real good at an accurate SG cell to cell comparison. And all balls rise usually means SG is between about 1.250 and 1.300, a pretty noticeable difference in battery real condition.

But yes, they will tell you if you've got a cell or battery heading south.

Sort of splitting hairs to find the "holy Grail" of perfect in an imperfect world.

There will always be some small discrepancy between cells, trying to achieve the exact same ideal 1.300 on every cell is pretty much a futile effort.

The discrepancy comes from slight differences in grids, how they are molded (grids can vary due to how much flash there is left after the molding) and composition of the lead, how close the grids are, variations in how straight the grids are, and even acid along with chemical reactions that have taken place from charge/discharge cycles not to mention possible stratification of the electrolyte. Everything also ages at different rates which can affect the SG between cell to cell.

Unless you want to spend $5K for a digital Hydrometer (they DO exist) your going have a difficult time to achieve the high accuracy you are after and even then, what if anything can you really do to correct the small insignificant variances you will see?

I am sure Mex knows a few tricks, but one must ask themselves, is the hassle to gain 2 minutes of battery run time worth the hassle and aggravation of jumping through a lot of hoops?

Batteries are a "consumable" item, use it and it is consumed, has a finite life and as such it wears out and you replace it with new and start the cycle over.