markjenn said:
Not exactly sure what you're recommending and perhaps we've discussed it previously in this thread, but my understanding of all lead-acid batteries (AGM, gel, or wet) is that deep-cycling (meaning where you discharge the battery nearly completely before beginning a charge cycle) is specifically NOT recommended as it dramatically shortens battery life.
- Mark
By placing a halogen headlight bulb in series with the charger, you limit the current flow. The bulb will glow, becoming dimmer as the battery reaches full charge. When the bulb is out (dark room) it is fully charged. I'm sure a milliamp reading meter would detect it, but that's getting more complicated than it already is. What you're doing by using the deep cycle charge is making sure you charge longer, not faster, from my understanding. By placing the bulb in line, not only do you have a visual indicator, but a form of series current limiting. I tried this a few years back on a neglected battery, and found that it worked very well, and that battery is still usable today. The valve regulated batteries are sealed, really sealed, unlike the ones that you can pry the caps off of. I'm thinking the complicated charging method has something to do with the hydrogen gas created by charging. If you charge too much, too fast, the gas could possibly cause the case to rupture or at least leak. I'm not sure of the complete mechanics of this, but it has worked this way for me after I was told by a battery guy from the battery company. others may get different advice, maybe my source was incorrect, but I can't argue with the results.
I swapped out the battery in my FZ either last season or the one before, and have kept it around just to see how long it would take some sort of charge. The original reason was it wouldn't keep more than about 12.4VDC after sitting a day after being on the charger, ridden for a while, or a combination of the two. Since the bike is very electrical oriented, I decided to get a new one rather than risk a problem on a ride. Even after basically sitting since I removed it, the removed battery hasn't gotten any worse. The new one charges up to about 12.8-12.9 VDC, and holds that for days of sitting. Since that time, since the older battery is just a testing device, I have tried all sorts of things on it, too see if anything I do, will do it in. Nothing so far. But I noticed my method mentioned above will give it a better, more thorough charge than either the battery tender or the sears charger straight up. Sometimes I can get it to hold a 12.6 VDC charge for a week after a charge. It makes for a nice test object.
Again, I don't claim to have the answers here, just what I have found works for me.