Ok, for our battery guru's, it seems to me that there are 2 competing opinions out there on charging to make batteries last and get fully charged to their max capacity.
Interstate Battery specifies some very high voltage requirements designed to prevent sulfation with each charge cycle. This seems to be the most often used, quoted and accepted method.
VDC Electronics - maker of BatteryMINDERs - contends that high voltage charging itself is damaging long term (due to the high temperatures generated?) They use a lower voltage charge (which they say is much safer) and then a patented temperature compensated float cycle that uses special frequencies to break up sulfuric acid crystal on the plates slowly. Avoid Battery Sulfation with a BatteryMINDer Battery Charger
Based on what I have read, Bob's satisfaction, reviews on Amazon, this BestConverter Review
, and the one full year 100% satisfaction guarantee, I bought one of their 12248 models.
My Interstates are 5 years old now and I have tried not to abuse them. The best voltage I was getting at full charge with the WFCO was 12.6 - 12.7 or so - measured after a 12 hour rest. The BatteryTender 5 amp model I had would get it into the 12.74 range. After 3 days on the BatteryMINDER it was up to 12.84. They recommend 72 hour charge, then retest until the voltage no longer rises. I'll keep trying to see if it will get any higher.