I think I have figured out the safe way to calculate the batteries. I figure all AA batteries at 1.25 amps. I then take my controller and read the max amp output and match the number of batteries to it. I will probably give it a little extra for Kentucky windage.

With the test proving that I can mix the batteries, I could have replaced the sla one at a time as they wore out. I think I am going to just order enough to complete the pack before I mess with them again. I am almost there and my sla pack is working just fine.