battery fluid replacement experiment
Thursday, January 5 2012
Today the weather seemed to be trending back to where it had been before the recent spate of seasonably-cold conditions. And through it all, our woodstove kept an eternal flame, one that hasn't need to be relit since the Winter Solstice. Technically, there have been times when the flames have dwindled away, leaving only coals. But these were able to quickly kindle up a flame with just a little tinder (pine cones that have been repeatedly run over by cars on Dug Hill Road are ideal for this) and puffs of breath.
This afternoon I did some experiments with the old Subaru battery, the one that Advance Auto Parts was refusing to take back because they claimed it was still "good." I wanted to make the battery so that it looked the same but functioned so poorly that there could be no doubt that it needed to be replaced. I could tell that it wasn't functioning well enough to use; after charging it overnight, I attached a 55 watt headlight bulb to it, but it was only able to power that bulb for about 20 minutes, whereas a cheaper, lower-quality car battery was easily able to power that same headlight bulb for well over two hours (it was still shining brightly when I stopped the experiment).
I knew I'd have to fill the battery with something other than its solution of sulfuric acid in order to kill it. So I popped open the caps and used a suction bulb to remove as much of the sulfuric acid as possible, and then I dumped out the rest, collecting it all in various bottles with the help of a funnel. This was a messy job, so I did it on the large plastic lid to the bin I'd used to present Gretchen her Christmas presents. The amount of solution removed came to about a gallon.
One idea for poisoning the battery was to fill it with some non-conductive fluid like alcohol, but that might have a tell-tale smell and could also constitute a fire hazard. So instead I filled it with distilled water. I could have used plain tap water, but (on the chance that Advance Auto Parts refused to take it back), I didn't want to completely destroy it with any mineral contaminants. Interestingly, though, even with nearly all of its acidic fluid replaced by distilled water, it functioned almost identically to the way it had functioned before; indeed, it might have actually worked a little better. By the way, replacing the fluid did nothing to lower either the voltage or the apparent charge the battery had been holding, so evidently that "charge" does not reside in the fluid. (I don't know enough about how batteries actually work to know whether or not the previous statement is absurd.)
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