No, the device shown here is not a battery charger,although it certainly looks like one. Rather, it's a Lester Battery Discharge Unit (or BDU), a gizmo I have been using recently to establish baseline data for some battery testing I'm planning to do onboard Betty Jane. What this particular BDU does is fairly simple--by means of a large interior coil it short-circuits a given battery in a very controlled way, precisely measuring the amount of time it takes for peak voltage to be drawn down to approximately 10.5 volts at a rate of 75 amps. This measurement (in minutes and seconds) gives a fair idea of the health of the battery being tested.
I used the device shown above last weekend on one of my three Deka Dominator 4D gell-cell batteries--I spared the other two mostly because I was slightly suspicious of the BDU's seemingly amicable personality. The point was to see what state this particular 5-year-old Deka was in--I'd synopsize it as flaky, flaky, flaky, given the numbers the dang thing spit out--so I can subsequently test the efficacy of a solar-powered product from an outfit called Pulse-Tech. This coming weekend I will hook the Pulse-tech product up to the Deka, expose the solar panel that comes with it to the sun in a semi-permanent way, and see what happens.
The Pulse-Tech is supposed to reverse some or even most of the sulfation activity that tends to sap a battery's strength. Of course, because tearing my Deka apart to determine exactly how much of its present weakness is due to sulfation and how much is due to other factors is an untenable option, there's no way to say exactly how effective any resulfation-type activity that may occur will actually be. But then again, an increase in battery strength after a little Pulse-Tech action would nevertheless be a fairly good common-sense indicator that the technology actually works.
I plan to let the Pulse-Tech run for approximately two months and then do another discharge test. With any luck, the Deka will be at least a little stronger.
Said test, by the way is just a tad spooky. The Lester tester gets almost hot enough to fry an egg on, any loose paint burns off, and the coil inside snaps, pops, and crackles. Of course, all this stuff is almost as much fun as some of the crazy experiments (the best entailed the inspired reinvention of gunpowder) I used to do as a kid. You'll be able to read about the results in the pages of PMY somewhere down the line.