Electrical

Battery Selection: Maintenance-type vs. "Freedom"

> I really don't see any relationship between no maintenance type batteries and
> electrical problems. In fact, batteries you have to maintain are often
> neglected to the point of sulfation and, if anything, you should have more
> problems associated with low voltage/capacity of these unmaintained batteries.
>
> Steve - 87S4/auto/GPW

Dear Steve:
At one of our monthly meetings, the PCA Potomac Region had a battery expert as a guest speaker. He showed us the difference between quality batteries and the usual "Freedom" batteries. The wall thickness that makeup the individual cells was the biggest difference. Most "Freedom" type batteries can get more CCA with more cell walls, but the walls are thinner are more easily damaged if subjected to vibrations. Also, many "Freedom" batteries have an indicator that shows the condition of the battery. Well, that's not correct. The indicator only shows the condition of the one cell it's connected to. The other five cells may or may not be functioning properly, but if that one cell is, the battery appears to be fine. With a maintenance battery, each cell can be accessed and have a hydrometer reading taken to indicate its condition.

If your "Freedom" battery is working fine, consider yourself lucky. I have found time and again, that they are not as good as maintenance batteries. In the nine years of 928 ownership, my electrical problems have been a few burnt bulbs and fuses. I think the fact that I use a very good Interstate battery has alot to do with my electrical good luck. YMMV.

One more thing. Except for Gel-Cell(sp?), all maintenance and "freedom" batteries are vented to atmosphere. Although "Freedom" batteries are suppose to be "sealed", they are not. A small amount of degassing takes place as temperatures increase and/or when the battery is subjected to heavy charging loads. Replacement fluids cannot be added to a "freedom" battery. They can and should be added to a maintenance battery.

When the fluids in a "freedom" battery gets below the upper level of the cell, that cell will be dead soon afterwards. If this occurs, the battery has 10 volts (at best). 928 computers have a very narrow operating range which starts above 10 volts. Thus, with only one bad battery cell, a 928 will probably not start. YMMV.

Merry motoring, Ed.