Desulfator
From Fusselman.org
Sulfation, basically, is the buildup of a sulfur compound on the lead plates of a lead acid battery. (those of you who know anything about batteries are probably appalled by this description, but it's adequate for our purposes). A desulfator, then, is a device for reversing this process, putting the sulfur back into solution with the sulfuric acid contained in the battery. This process was initially conceived for large flooded lead acid battery banks, though it also seems to function on smaller SLA and AGM type lead acid batteries.
Outwardly, sulfation manifests itself as a decreased storage capacity, and in severe cases, the inability to charge properly. Shorted or otherwise damaged cells are not sulfation, though some sources refer (incorrectly) to many battery maladies as "sulfation".
Initially, I had planned on building my own desulfator, based on plans by Frank of Theworkshop.ca. To that end, I acquired an oscilloscope and started doing research on oscillators. Needless to say, that didn't go too well, for a variety of reasons. In the end, I determined that the desulfator was a "gateway project", required for almost all of my other alternative energy projects, but not something I particularly want to undertake for its own purposes. As a result, in an uncustomary display of spending, I went out and ordered one. I decided I just had too many things waiting on this one, relatively inexpensive device.
I ended up ordering a VDC Electronics "BatteryMINDer" desulfator (Model# 12117)from BatteryMart (via Amazon) for $53 shipped. This device has a built-in trickle charger (1.3A) to keep the battery full, while being desulfated. It also claims to use patented battery restoration technology. It remains to be seen how this varies from classic desulfation methods.
Anyhow, upon receipt, I promptly hooked it up to the "best" of the batteries I intend to use on the bike and put it to work. Shortly, I pulled out the 'scope to see what the commercial desulfator was doing. I was surprised to find that it's significantly different from what Frank describes in a more traditional desulfator.
The classic design uses a "ringing" 35v spike at a frequency of about 1khz. The BatteryMINDer, on the other hand, seems to use pulses of about 15 volts with no pre or post pulses, at a rate of about 2khz. Perhaps more importantly, the 'scope has a hard time triggering to fix the waveform, which suggests that the timing of the pulses is not terribly precise, though the manufacturer suggests that the charger is microprocessor controlled. Initially, the behavior of the BatteryMINDer was different, and I wonder if the output varies over time within the desulfation cycle.
TheWorkshop.ca has been gracious enough to let me display the traditional waveform here, alongside the "new" one.
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| The Classic waveform | The BatteryMINDer waveform |
Updated
I'd been meaning to write a followup to that article but just never got around to it. I got an email from a reader today asking for some further feedback. Here's the bottom line:
Basically, I ended up with the BatteryMinder because it was available through Amazon and I had an amazon gift card in hand. There are a few other options available (like building one yourself or ordering one from Mikey of Holy Scrap Hot Springs). The main difference in my mind is that the battery minder has a lot less "desulfating action" (ie the pulse peaks are lower, as measured with my scope), but it has the advantage that it's an intelligent charger as well. If you're hoping to breathe new life back into old deepcycle or golfcart batteries, I'd highly recommend one of the other options (neither of which I have, though the proof is in the scope traces). The BatteryMinder works for this, but it takes a while, and has some annoying side effects namely operating only on 12v batteries (bad if you have 6v golfcart batteries) and it only cuts in the desulfator "once the battery is charged". If the battery voltage doesnt get to a pretty high point (like 11v I think), it wont let you engage the desulfator at all, even manually. This means that there's a lot of "dead" batteries out there that the BatteryMinder can't do anything for.
All that negative stuff said, if you're hoping to maintain and "float charge" your sports car or boat battery over the winter, the BatteryMinder is a great option. From a user-interface standpoint, it's a no brainer. Nice long 12v cords, includes battery clamps as well as ring terminals, and a quick disconnect, so the rings can be left on the car year-round. Single button user-interface to manually start desulfation if you dont want to wait, etc.
Basically, it all boils down to what you want to use it for, and what you expect it to do.
