So I was looking at the wall warts I have laying around when I realized that my portable jump starter came with one to charge it up. I checked the voltage without it connected to anything and it was about 18 even though the label says it should be 13.5V. So then I thought I'd plug it into the jump starter, let it fully charge and see where it stabilizes (still plugged in). Turned out to be 14.9V which I think is just about perfect. So, rather than ripping the plug off of a wart, I'll just try connecting the jump starter to the Interstate. Should yield about the same results.
I calculate the SOC of the Interstate to be about 75% currently so I need to add about 20AH to get to 100%. At 300mA we're looking at at least 66 hours. I'm going to continue to check the voltage and SG each day and see how well this works.
