BWST: This Amazon review explains equalization vs desulfating better than I ever could:

"5.0 out of 5 stars A must have..., December 11, 2009
By remote camper This review is from: BatteryMINDer Model 12117: 12 Volt 1.33 Amp (12V 1.33A) Charger/Maintainer/Desulfator (Misc.)
...if you own deep cycle batteries. I bought one of these in 2001 as an experiment to desulphate eight 6 volt 225 amp hour deep cycle batteries.

***EDIT May 9, 2013***
Contacted VDC Electronics yesterday to obtain information on the suitability of the 12117 for use with deep cycle batteries and learned that the model # for which the results in this review were obtained were actually for a Model# 12112, the predecessor to the 12117. The 12117 wasn't introduced until 2006. I had misread the model # on my unit when I wrote the review in 2009. I apologize for the error. That said, the 12112 and the 12117 are virtually the same technology with the 12117 having increase in output of about 30%. That would seem to speak fairly favorably of the results I obtained with the lesser powered unit.
VDC Electronics has confirmed that the 12117 "can be used with deep cycle batteries as a maintainer/desulfator", contrary to what the Amazon specifications might say. However, the 12117 is NOT certified for use with AVIATION batteries. The remainder of the original review continues below.
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The RV park where we were staying used these deep cycle batteries in their golf carts. They were going toss them in the dumpster because they were having to recharge them too often. These batteries were in bad shape as evidenced by the constant 6 amps being drawn after being hooked up to their "super" charger for many hours. Essentially, these batteries were so sulphated that they would not accept any more charge. With many chargers the charge current will drop to "0" as battery resistance increases when fully charged.
I mentioned tossing the batteries in the dumpster might be illegal. If they let me have them to do some tests and possibly recover them, I would dispose of them properly if I had no luck. I had just installed a solar panel system with a 2500 watt inverter on my 5th wheel and had only 1 pair of golf cart batteries that was already at least 2 years old. I needed more reserve battery power and calculated that I would need at least 6 of these batteries for the inverter to be of any real use to me. When using batteries in this manner, it is best to use batteries that are in similar condition and ideally from the same lot. Six new batteries were going to cost about $520 with tax.
I got them back to my rig and baselined the charge they would accept on my 10 amp charger. Indeed, they were not accepting any more charge. I paired these old batteries in series to get four 12 volt configurations and spent the next 4 weeks (1 week per pair) on this desulphator. I continued this process until my charger's ammeter would go to zero when the batteries were full, an indication that they were now in good shape. Ultimately, 2 of the batteries would prove to be unrecoverable, but the other 4 plus the 2 I already owned eventually recovered about 90% of their original amp hour capacity based on some standard tests I ran.
My inverter, combined with these recovered batteries, would run my 15,000 BTU air conditioner for nearly an hour, more than enough time to cool our 5th wheel while preparing and consuming lunch in 106 temps in Ca. deserts. The batteries would be nearly fully recharged by the solar panels and charge line from the tow vehicle by the time we reached our destination for the evening. With loving maintenance and care, they had lasted another 5 years providing countless hours of dry camping service! Finally, in 2006, I replaced them with new ones before an extended camping trip.
This charger/desulphator requires 115 vac and a minimum of 11 volts in the battery before you connect to it. So, if your battery is dead, be sure to bring it up the 11 volt minimum before hooking the unit up or it could overheat and be ruined. Also, most of the cheaper old style battery chargers don't have any voltage regulation. Consequently, the voltage these chargers supply to a fully charged battery can exceed well over 14 volts and will eventually "cook" the electrolyte out if you leave them hooked up. They can also overheat the battery, permanently damaging the thinner plate structure of automotive (starting batteries). The VDC model I bought in 2001 can be left on to maintain the charge in lead acid batteries. Check your operator instructions to be sure.
Shortly after recovering these batteries, I bought another desulphator from an Arizona solar supplier capable of desulphating a 1600 a/h battery bank that operates only off of the battery bank. This constant desulphating process along with proper battery maintenance is probably what helped sustain these batteries for an additonal 5 years. In the absence of a desulphator, deep cycle batteries should be "equalized". The interval depends on usage. I was doing it monthly. The equalization process requires a special charger and can be hard on batteries. Desulphation performs a similar function without the harshness of equalization. Desulphation plus judicial use of equalization can extract maximum life out of your deep cycle batteries. I wouldn't be without either one of these desulphators or a 3 or 4 stage battery charger.
A final note: Never let your batteries sit in a discharged condition. As a battery discharges, the sulphate that forms will be easier to return to solution whn prmptly recharged. If you let it sit, the sulphate can harden and be nearly impossible to return to solution. "

I also came across a BatteryMinder vs CTEK review on Amazon by a guy who seemed to know what he was talking about. His owns both. His conclusion? He is impressed with both and despite their differences has no preference between the two. Unfortunately, I cannot find that review.

 

Tim, thanks for posting this. Good info to digest. For battery switches, I'm replacing the Guest switch with a Blue Sea Systems unit I found on amazon - plenty of good reviews on it, might be an option for you. I would probably steer clear of the HB versions.

 

This was posted on the Sportsmobileforum.com. It is an excellent article on batteries, types and differences, charging, etc.

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