The K2 batteries purchased 6 years ago, and the Stark Power Systems Batteries that I replaced the K2's with both have internal battery management boards in them that are supposed to prevent under discharge, over charging, and provide cell balancing. The Stark battery pricing on their website is exceptionally attractive right now. However I can't guarantee that they are any better or worse than any of the other batteries of this type currently for sale.

Someone else in this thread mentioned that these boards do not do quite as good a job at cell balancing as what is normally used on a much more expensive battery packs, and that they need an extended period on float charge to re-balance.

Currently I have discharged the K2's and they are now on extended "float" charging to see if the cells re-balance after several days on float.

I don't have a lot of hope for the re balancing attempt. The discharge graph for the K2's in their current condition isn't typical for Lithium batteries. It looks more like the typical SLA battery discharge graph. In my professional opinion some of the magic smoke came out, and as we all know that just never goes back in again.

The point of all this was to give everyone a heads up that these things don't appear to last forever. I got 6 years out of them, and that's not too bad for a battery.

The Mountain Radio battery tester is a neat looking piece of equipment, but it lacks the mad scientist look of the six marker lights screwed down to a 2 x 6. Don't discount the entertainment value of aggravating everyone in the house when the timer on the stove goes off every thirty minutes during the testing either.

SF